摘要:

THE QUARTERLY JOURNAL OF THE CHEMICAL SOCIETY. IX.-On the Composition of the Waters of the Dee and Don at Aberdeen with an Investigation into the Action of Dee Water OR Lead Pipa and Cisterns. BY JOHNSMITH,M.D. FORDYCE LECTURER ON AGRICULTURE AND ASSISTANT IN THE LABORATORY OF MARISCRAL COLLEGE. I.-GENERAL CHARACTER OF THE DISTRICTS DRAINED BY THE RIVERS DEE AND DON. The sources of the Dee are found amidst the lofty granite mountains of Braemar on the confines of the counties of Banff Inverness and Perth. The river flows from thence in an easterly direction along a narrow valley till it falls into the sea at Aberdeen its length being about 80 miles or when measured in a straight line 65 miles. The river-banks are gravelly and the alluvial deposits few andof limited extent.The bounding ridges of the valley are mostly of granite and gneiss. The flow of' the water is pretty rapid the alteration of level between the Linn (16 or 17 miles below the source) and Aberdeen being nearly 1200 feet. From the small proportion of clay and peat in the valley of the Dee its waters are VOL. IV.-NO. XIV. K 12'4 DR. SMITH ON THE WATERS usually quite clear ;in rainy weather however they are often charged with mud from the swollen mountain-torrents. The Dee and its tributaries drain about 900 sqnare miles of country. The rocks near the sources of the Dee are granite and quartzose mica-slate. Though very insoluble in their nature these rocks will by slow decomposition yield to the water minute portions of silica potash and iron The springs of the Dee must however be very pure.Further down the river receives water that flows over patches of crystalline limestone and a tributary (the Muick) passes along a serpenfiine range. From these rocks the water will derive a small proportion of lime and magnesia. Proceeding still farther down the rocks present no variety; granite and gneiss with occasional veins of felspar-porphyry and more rarely patches of limestone making up the geology of the district. The water for the supply of Aberdeen is taken from the Dee about two miles from its mouth and quite beyond the reach of the tide-water. It percolates through the gravelly sides and bottom into drains and is thence pumped up to the highest level of the town.It is distributed through iron mains and taken into houses by small lead pipes to which lead cisterns generally of moderate dimensions are commonly attached. The supply is constant and amounts to about one million gallons per day. The district drained by the Don lies immediately north of that drained by the Dee and is of much less extent. Rising in mossy ground encircled by granite hills on the borders of Banffshire the Don pursues a winding course of about 60 miles to Aberdeen. A straight line from its origin to its termination is about 42 miles. Tlie mountainous region drained by the sources of this river although mainly granitic has more limestone and serpentine than exist about the Dee and hence more lime and magnesia niight be expected in the water.At Kildrummy the Don passes through a range of old red sandstone. A few miles below this the hills recede from the river and enclose the fine valley of Alford. A4fter emerging from the hilly country at Monymusk its progress is tortuous and slow through alluvial meadows and an open country till within a few miles of its termination when it again flows rapidly. ,4bout 18 miles from the sea it receives its largest tributary the Ury which drains a fertile country and has a course of about 24 miles before losing itself in the Don. After rain the water of the Ury is commonly tinged yellow with clay while the Don itself has more of a brown colour from peat. The Don water at Aberdeen is rarely of such linipid clearness as that of the Dee.OF THE DEE AND &ON. 125 ~I.-COMPOSITION OF DEE WATER. The specimen (A)subjected to analysis by the ordinary methods was collected some miles up the river on Sept. 24th 1850 three days after heavy rain. The river was about its usual size the rain having been preceded by a long-continued drought. The water had a brownish tint from vegetable matter aad on close inspection minute specks and hair-like bodies could be observed floating in it. These could be removed by filtration which however did not sensibly improve the colour. The vegetable matter was perceptible to the taste. The water contained little or no air and I have observed on several other occasions that when the water is coloured by organic matter it is deficient in air.The Dee water in its ordinary condition is colourless and is well often bighly aerated. The solid matter found in a gallon of specimen A was constituted as follows Lime. . * . . 0.526 grains. Magnesia . . 0*110 ) Potash and soda . . 0.382 , 0 Carbonic acid (in combined state) . . 0.374 , Sulphuric acid . . 0.275 jj Chlorine . . . 0.338 , Silica . 0 . . 0.140 , Precipitate by ammonia from acid solution . 0*080 , 0 Organic matter and loss . . . 1.775 , . 4.000 Total . The acids and bases may be arranged thus Carbonate of lime . 0.850 grains. 0 0 Sulphate of lime . 0.121 , , magnesia 0.323 , Chlorides of potassium and sodium . . 0.670 , Phosphate of lime and iron 0*080 )) Silica .. . . 0.140 , Organic matter and loss 1.816 j 4000 In this scheme I have supposed the sulphuric acid to be increased by -009grain in order to make it take up the whole magnesia. The alkalies were determined together ; but in the qualitative exami- nation potash was readily detected in the residue of 1gallon. K2 DR. SMITH ON THE WATERS The dry residue obtained by evaporating the water not being deli- quescent on exposure the absence of earthy chlorides was inferred. In the precipitate by ammonia from an acid solution the presence of lime and iron was detected but the proof of phosphoric acid was incon- clusive. Operating afterwards however on the solid contents of a much larger quantity of water (about 15 gallons) this acid was shown pretty distinctly.The dry residue of 1gallon gave no indication of nitric acid when tried with sulphuric acid and sulphate of iron. Boiled with carbonate of soda it gave distinct proof of ammonia. The quantity of organic matter in specimen A was much larger than the Dee water usually contains; iiideed the brown tint caused by it was very well marked. A portion kept in a glass bottle for some months deposited a brownish sediment and became clearer. It was then found to contain only 1 grain of matter volatile on ignition. A specimen (B)taken from the same part of the river on the 15th of February 1851-the river being of its usual size and the water clear and coloudess-gave 3 grains per gallon of solid matter of which only -#hs of a grain were volatilized by ignition.It is in accordance with general experience that organic matter in water is least abundant during the winter season. A gallon (C)drawn from the laboratory pipe on the 26th of September (the water being colourless) left the same quantity of dry residue and gave off about 0.8 grain on igni-tion. In experiments at different times I have thus found the solid matter (dried at 212') to vary from 3 to 4 grains per gallon; and the matter volatilized by a low red heat (generally reckoned organic matter though it probably always exceeds the true organic matter in amount) to range from T*Oth~ to 12 grains. III.-ACTIONOF CLARK'S SOAP TEST ON DEE WATEB. In many trials of Dee water taken either directly from the river or from the laboratory pipe the hardness was found to vary between 1O.1 or 1O.2 and 1O.75.But different trials of the same specimens have sometimes varied a little-such a variation as I have been accus- tomed to find in solutions of very low degrees of hardness especially when this hardness is caused partly by magnesia. In specimen A the hardness varied in three trials from 1O.1 to 1O.14. After standing a day or two the lathers could not be renewed without a further addition of soap-test raising the hardness thus in two of the cases to 1'036. Taking the mean between the highest and lowest we may assume the hardness of specimen A to be 1O.23; and this agrees accurately with three trials made on water drawn from the laboratory OF THE DEE AND DON.pipe on the 28th of September which should not have differed much from river water of the 24th. The greatest hardness observed was in specimen 23 taken direct from the river on the 15th of February. It turned out 1O.75 ; but as the specimen was highly aerated it is just possible that a little of this apparent hardness may have arisen from carbonic acid. In specimen A I distinguished the hardness caused by lime from that caused by magnesia by means of the soap-test as follows A mixture of equal bulks of standard lime solution 20' and distilled water was tried and the hardness noted. A similar mixture of same solution 20' and specimen A was then made and the hardness deter- mined. The difference was 0'047. This multiplied by 2 (as the Dee water operated on was only half the standard quantity) gives OO.94 the hardness caused by lime ; and subtracting this from 1O.23 the total hardness leaves 0'*29 as the hardness resulting from mag- nesia.By an extended course of experiments I had previously satis- fied myself that the soap-test is not affected by any quantity of magnesia under 6O or 8O if associated with at least 10' of lime; hence the contrivance of the above experiments. If the whole lime in the water as given in the preceding analysis page 125 (omitting what may exist in the precipitate by ammonia) be calculated as car-bonate the amount will correspond exactly to that indicated by the soap-test namely 0.94 grain ; and if the magnesia in like manner be calculated as carbonate of lime it will turn out 0.26 grain dif- fering very little from the soap-test result; and in the case of mag- nesia it is to be expected that the ordinary analysis will give under the truth.The quantity of pyrophosphate of magnesia aEorded by a gallon of water (A),I have noted at 0-30grain. If this be made 8.32,it will correspond exactly with the indication of the soap-test. This new application of the soap-test promises to be of considerable utility." IV.-COMPOSITION OF DON WATER. Two specimens were examined. One (A)was taken on the 4th of October from the river about a mile from its embouchure quite beyond the reach of the tide. The other (B)was collected near the Bridge of Alford (about 35 miles up counting the windings of the river) on the same day and about nine hours previous to the collection * The Culter Burn a large tributary of the Dee which drains the Loch of Skene and surrounding country I found to contain at its confluence with the Dee (about 8 miles up) on the 26th of September 6 grains of fixed salts per gallon with 2 or 3 pains of organic matter additional.Hardness 3O.1. DR. SMITH ON THE WATERS of specimen A. The river was in its average condition. Specimen A was tinged brown with vegetable matter which also affected the taste. Flocculi of organic matter were seen in it and brown specks of iron and organic matter speedily subsiding on rest. No air-bubbles emitted on exposure By careful evaporation the solid matter was found to be in the proportion of 8.64 grains per gallon and of this there were 3.04 grains volatilized by ignition.The composition of the dry matter was as follows Lime . . 1.29 grains. Magnesia . . *34 Y Alkaline chlorides containing 0.74 of chlorine 1.32 , Carbonic acid (in combined state) . . 96 ,J 0 Yt Sulphuric acid . . *76 0 $9 Silica . . . . *GO Precipitate by ammonia from acid solution . *38 ,Y Organic matter . . . 3.00 ), -0 0 Total . . 8.65 The acids and bases may be taken thus Carbonate of lime Sulphate of lime . . . 2.18 grains. *I7 ,t , magnesia . 1.00 , Chlorides of potassium and sodium. Phosphate of lime and iron . . . 1.32 *38 ,,,) Silica . . *GO ? Organic matter . . . . 3.00- I 0 Total . . 8.65 Specimen B was very faintly tinged with vegetable matter and contained some floating specks of the same.On evaporation it left at the rate of 5 grains solid matter per gallon of which 3%were fixed salts and 1-2 volatile (organic matter). Hardness of Don Water.-The soap-test with specimen A gave 349 with B a&". The hardnessof A calculated from the above table isy for lime 2O.32 for magnesia 0°*82;together equal to 3O.14. The phosphates would add something to this I had not an opportunity of applying the new soap-test process to this specimen in its original state. After being kept four months in a stoneware jar the water was found to have increased in hardness to 4O.2 The total solid OF THE DEE AND DON. matter per gallon had increased to 9.6 grains while the organic matter remained precisely as at first 3-04grains.On applying the soap- test to separate lime or magnesia in the manner already described the hardness owing to lime was found to be 3'04 and that from magnesia OO.8 while the lime had thus been increased by impurity from the jar the magnesia appears to have remained unaltered. IV.-ACTIONOF DEE WATEB ON LEAD. Under this head I have recorded about forty trials made at dif- ferent times and on water from houses in various parts of the town; besides upwards of a dozen experiments with lead bars in specimens of water not previously in contact with lead. In the sequel I shall make such a selection from these trials as may serve to bring out the conclusions arrived at. Mode of cperating.-The test used was sulphuretted hydrogen ; the water being previously acidulated with hydrochloric acid and the gas transmitted a suflicient length of time.In the earlier trials I used only one or two pints of each specimen but it soon became apparent that much greater delicacy was attainable by employing a larger quantity. In proceeding with the experiments therefore I operated uniformly on a gallon contained in a glass beaker of such dimensions that the water had a depth of 104 inches. By placing the beaker on a piece of white paper and looking downwards I was able to appreciate a very slight change in tint. Anot-her similar vessel with the same quantity of water was always placed by the side of the first for the sake of comparison. In estimating the quantity of lead present in any case I had recourse to a very simple expedient.A solution of lead was prepared of definite strength ;chloride of lead was used at first but afterwards pure nitrate as more convenient. 1.6 grain of nitrate was dissolved in 1000 grains of distilled water so that the solution contained 1 of metallic lead in 1000. From an accurately graduated measure I dropped this solution into a gallon of water containing no lead until on transmission of sulphuretted hydrogea the same depth of tint was developed as in the particular case on trial. Having come as near as possible to the right quantity in this way I commonly then made a new mixture adding at once the ascertained quantity of lead to a gallon of water and transmitting the gas. If the two trials corresponded the experiment was finished but in case of any discrepancy the trial was repeated.This method I believe will give very accurate results until the quantity of lead exceeds t grain per gallon when the colour gets so dark that slight DR. SMITH ON THE WATERS differences cannot well be discriminated. I found that &th of a grain of lead added to a gallon of pure clear water gave a tint quite percep- tible that is 1of metallic lead in 7 millions ; and a less quantity could readily be distinguished by careful comparison. Even in specimens previously containing a considerable proportion of lead the difference of of a grain was plainly visible. Here is an instance A gallon of Dee water taken from a leaden pipe having Siven a certain tint with sulphuretted hydrogen a gallon of Dee water not containing lead was placed beside it and 80 grains of the standard solution (containing 0.08 grain of lead) well mixed.By the action of sulphuretted hydrogen the tint produced was a little lighter than in the other; 10 drops more made the tints equal; and again 10 drops rendered the last somewhat darker than the first. Now every 10 drops of solution con-tained 2 of a grain of metallic lead. The preliminary acidulation with hydrochloric acid is very essential when the water under trial happens to contain any iron. In some spring waters that I examined there was a blackening caused by sulphuretted hydrogen from the presence of iron in combination with organic matter. Acidulation with hydrochloric acid entirely prevents this blackening or destroys it after it has been produced leaving a milkiness in the water from deposition of sulphur.To ascertain if the hydrosulphuric acid test would be affected by a minute quantity of iron I dissolved 1grain of the pharmaceutical ammonio-tartrate (which would contain about +th of a grain of metallic iron or +th grain of red oxide) in a gallon of water. The solution had a greenish-yellow tint. On transmitting the gas there was no change €or some time but ultimately an evident darkening with deposition of sulphiir. Selection of trials of Wuter from House-pipes (Zead). -Speci-mens taken during the day when the water would be in its usual condition unless stated otherwise. 1. Pipe about 16 yards long-no cistern-no indication of lead.2. Pipe 12 or 15 yards-no cistern-specimen drawn first in the morning showed a trace of lead (less than & of gr. per gallon) specimen drawn at mid-day-no lead. 3. Pipe about 36 yards-no cistern-about & of gr. metallic lead per gallon. On mother occasion this pipe gave rather more lead. 4. Pipe upwards of 100 yards-no cistern-tried on different days the quantity of lead varied from & to 4 gr. per gallon. 5. Pipe 16 or 18 yards-small cisternlead under & gr. per gallon. 6. Pipe about 24 yards-cistern-several families supplied and much water used-no indication of lead. OF THE DEE AND DON. 7. Pipe about 15 yards-cistern-& gr. of lead per gallon. 8.Pipe about 30 yards-cistern-about f gr. of lead per gallon. 9. Pipe about 100 yards leading into cistern with about two cubic feet of water,-& gr. of lead per gallon This being the largest quantity I have found in any water in ordinary domestic use I made particular inquiries in regard to the health of the family. Nothing unusual had ever been noticed except that on coming into town for the winter (the family lived in the country during summer) the children speedily lost colour. This of course is usually attri- buted to the air of the town but it would be worth inquiring how much of the effect in such cases is due to the water. This case however shows that water containing kth of a grain of metallic lead per gallon (equal to 4 gr.carbonate) may be used habitually without any notable injurious results. Mr. W. Herapath related a case in the “Times” (14th Sept. 1850) where +th of a grain of lead per gallon deranged the health of a whole community. The limit of the deleterious action would seem thus to be somewhere between & th and th of a grain. 10. The leaden pipe supplying Marischal College afforded some instructive points. It is upwards of 100 yards long. Specimens of water drawn before entering any of the cisterns contained as stated in case 4 from f to & of a grain per gallon. About the middle of the pipe a branch is taken off to the porter’s house where it dis-charges into a small cistern. Water taken from this at different times contained +3 to $ of a grain of lead per gallon The college pipe near its termination supplies a cistern containing usually about 10 cubic feet of water.A specimen taken direct from this cistern I found to contain f or & of a grain of lead. A specimen taken at the same time from a pipe that proceeds from this cistern about 20 yards contained -+Tof a grain. The pipe was allowed to run a good deal before the specimen was drawn. Tried at various times this pipe afforded from Q to $ of a grain of lead per gallon. Another pipe from the same cistern after remaining a day or two unused contained sometimes + or even + of a grain per gallon. Selection from Experiments with Lead Bars.-1. Bar of bright lead immersed (to the extent of 23 square inches of surface) in 2 pints of Dee water-left 48 hours-water remained clear-no deposit-a thin whitish film had formed on lead.The water after filtration through double filter contained about & of a grain of lead per gallon. 2. Parallel experiment with distilled water water speedily became DR. SMITH ON THE WATERS milky-abundant white deposit. Passed several times through double filter but milkiness not removed After standing two days the white matter subsided and the water then filtered clear. No lead whatever in solution. (The oxide was probably entirely converted into insoluble carbonate by exposure.) 3. Bar No. 1 immersed without cleaning in 2 pints of Dee water and left 48 hours-no deposit. Passed through double filters the water contained about & of a grain of lead per gallon.4. Bright bar in 3 pints of Dee water-32 square inches irn-mersed-left 24 hours-filtered-con tained trace of lead. 5. Same bar without cleaning in 2 pints-26 inches immersed- left 48hours-filtered-contained -&of a grain of lead per gallon. 6. Lead bar tarnished in air immersed (to 30 square inches) in 3 pints-left 48 hours-filtered-; of a grain of lead per gallon. 7. The bars used in experiments 5 and 6 were placed without cleaning in similar quantities of water and left 48 hours-not filtered. The water from bar 6 contained about & of a grain of lead per gallon. The water from bar 5 contained more. 8. The bar from experiments 5 and 7 being again immersed without cleaning and left 48 hours the water unfiltered contained much more lead than in last experiment-about 4-of a grain per gallon.9. Same bar left 48 hours in 2 pints-water passed through double filter contained about of a grain (or rather more) of lead per gallon 10. Bar of bright lead immersed in 2 pints of Dee water for 4days. The water had been kept for some time in a jar in a warm room so that a great part of the air had escaped from it. After filtration the water contained a mere trace of lead. Bar immersed again without cleaning in other 2 pints of same water and left for 2 days. Water (filtered) contained more lead than in last case but still not much.* From these experiments it appears that Dee water acts more readily upon tarnished or crusted lead than upon the bright metal; that the lead taken up by the water is separated to a small extent by paper filters; and that when a crusted bar is immersed for 8 certain time in water dried and immersed again for the same time the action is greater the second time than the first; dried and immersed a third time the action is still greater.(So that a lead cistern alternately filled and * The lead used in these experiments was the kind commonly empIoyed for lining cisterns-7 or 8 lbs. to the square foot. Fresh portions of Dee water not previously contaminated by lead were used in each case. OF THE DEE AND DON. emptied is more unsafe than one kept constantly at the same level both *being freely exposed to the air.) From the foregoing observations I conclude that the action of Dee water on lead is comparatively feeble but yet that by prolonged con- tact more especially when there is free exposure to air as in cisterns a dangerous quantity of that metal may be taken up.With lead pipes of moderate length and no cisterns no danger whatever is to be apprehended. With small cisterns and a pretty constant use of the water there is also no danger; but the risk increases with the length of the pipe the size of the cistern and the time the water lies unused. When large cisterns are required for general domestic use I think it would be prudent to have them lined with gutta percha or sonie other innocuous material. With an uninterrupted supply such as is enjoyed in Aberdeen and with an improved form of tap cisterns might probably to a great extent be dispensed with.In some cases it has appeared to me that old pipes are more acted upon than new ; the differences however may have arisen from impurities in the lead or from other special causes not detected. I am also inclined to think that the action on lead depends greatly on the aeration of the water. In rainy weather when the Dee water is coloured and contains little air the quantity of lead dissolved in any case appears to be less than when the water is clear and well aerated. This observation has been confirmed to some extent by the experiments with lead bars but I am not prepared to state it unreservedly as a rule.

ISSN:1743-6893    

DOI:10.1039/QJ8520400123

出版商:RSC    

年代:1852

数据来源: RSC

摘要:

OF THE DEE AND DON. X.-On a peculiar Property of Ether and some Essential Oils. BY C. F. SCH~NBEIN. It is now a well-known fact that phosphorus on being put under certain circumstances in contact either with pure oxygen or atmo-spheric air produces a highly oxidizing agent capable of discharging the colour of indigo-solution eliminating iodine from the iodide of potassium transforming the yellow prussiate of potassa into the red salt changing a number of metallic sulphides into sulphateu &c. From the statements hereafter made it will appear that besides phosphorus there are some other oxidable matters enjoying the same property. 134 MR. SCHONBEIN QN A PECULIAR PROPERTY OF ETHER I.-ETHER. A large colourless glass bottle being charged either with pure oxygen gas or atmospheric air and holding some recently prepared pure ether was put up in a room receiving but diffusedlight and now and then shaken.After the lapse of four months,the ether exhibited the following properties 1. No action upon blue litmus-paper. 2. Water fairly black by indigo solution on being shaken with the ether became colourless more rapidly so on heating the mixture than in the cold. Strips of linen fairly dyed by indigo solution and sus-pended within a large bottle containing some ether were completely bleached within a couple of days. 3. The ether on being put in contact with pure phosphorus rapidly tnrned sour phosphorous acid being formed. 4. The ether on being shaken with a solution of pure iodide of potassium turned brownish-yellow acquiring the property of colour-iug dark blue the paste of starch A dry strip of my ozone test-paper (prepared by drenching white filtering paper with a thin paste of one part of iodide of potassium '10 parts of starch and 200 parts of water) moistened with the ether soon assumed a brown and if then wetted with water a dark- blue colour.The same test-paper being moistened with water and suspended in the ether vapour turned dark blue within a few hours. 5. The ether on being shaken with a solution of pnre sulphate of protoxide of iron caused the transformation of that salt into the basic and acid sulphate of sesquioxide of iron more rapidly so on heating the mixture than in the cold. 6. The white cyanide of iron (obtained from the yellow prussiate of potassa and pure sulphate of protoxide of iron) on being shaken with the ether instantly turned dark blue.7. A colourless solution of the yellow prussiate of potash on being shaken with the ether turned yellow (in consequence of the forma- tion of the red salt). 8. White filtering paper coloured brownish by sulphide of lead on being immersed in the ether turned white again within a couple of hours the sulphide being transformed into the sulphate of lead. Strips of sulphide of lead paper suspended within bottles holding some ether appeared completely bleached in a few hours light being entirely excluded. 9. Filtering paper coloured yellow by sulphide of arsenic and immersed in the ether was bleached in a few days.AND SOME ESSENTIAL OILS. 10. Aqueous sulphurous acid on being shaken with a sufficien'; quantity of the ether was rapidly and completely transformed into sulphuric acid. 11. The ether on being repeatedly distilled over lost its oxidizing powers. It is hardly necessary to say that recently prepared ether or old ether carefully preserved from contact with atmospheric air leaves the ozone test-paper entirely unchanged and exhibits no oxidizing action whatsoever. It being very likely that the oxidizing principle w'e have traced in ether enjoys peculiar physiological properties ether having been for some time in contact with atmospheric air ought perhaps not to be used for medical purposes. It is not impossible that some of the deleterious effects which have been observed to be produced by the inhalation of ether vapour are connected with our oxidizing prin- ciples.TI.-ESSENCEOF TURPENTINE. Different as this oil is from ether as to its chemical constitution it nevertheless in some respects resembles the last-named substance. Oil of turpentine like ether at the common temperature takes up oxygen giving rise to the formation of acetic acid and a highly oxi- dizing matter. A large colourless glass bottle being charged either with pure oxygen gas or atmospheric air and holding some fresh oil of turpentine was put up for about four months* in a room receiving only diffused light and shaken and opened now and then ;after this * Since this paper was written I have ascertained that oil of turpentine may in a much shorter time be oxygenated to a considerable extent.Shaking frequently the essence with insolated oxygen or atmospheric air will lead to that result. In the way indicated I have succeeded in preparing within a couple of weeks oxygenated oil of turpentine which is capable of discharging the colour of 36 times its weight of my standard indigo solution. Pure oil of turpentine having for the same length of time been kept in contact with dark oxygen does not yet exhibit any perceptible degree of oxidizing powers. Hence it appears that light independent of heat very much favours the oxygenation of the oil of turpentine &c. To convince yourself of that action of light cover the bottom of two white bottles holding atmospheric air with chemically pure oil of tuppentine suspend in either of them a moist band of my ozone test-paper darken one of these vessels and expose the other bottle to the action of direct solar light and you will within a few minutes per- ceive the edges of the test-paper suspended in the insolated bottle to assume a violet tint and the who:e paper turn dark blue in an hour or fifty minutes whilst the test- paper in the dark bottles has during the same space of time not undergone any perceptible change.Strips of linen dyed by indigo solution will remain unchanged in the darkened bottle and be bleached in the insolated one &c. 136 MR. SCH~NBEINON A PECULIAR PROPERTY OF ETHER time the essence had acquired the property of reddening strongly blue litmus-paper and a very strong oxidizing power as will appear from the following statements 1.Water rather strongly blued by indigo-solution on being shaken with the oil soon lost its colour more rapidly so at a raised tempera- ture than in the cold. One gramme of the oil on being poured into a boiling mixture of 100 grms. of water and 5 grms. of il strong indigo-solution discharged the deep-blue eolour of the liquid as rapidly and completely as if chlorine or bromine had been used instead of essence of turpentine; and the oxidizing power of the oil was not yet entirely exhausted it being still able to destroy 3 grms. more of the indigo-solution so that the oil could destroy fully eight times its own weight of the strong solution.I hardly need say that to obtain the full oxidizing effect of the oil upon the indigo-solution it is required to shake both the liquids briskly together while they are heated. Moist strips of linen coloured light blue by indigo-solution on being immersed in the cold oil became white in two hours and in the hot essence almost instantaneously. Bits of linen cloth coloured light blue by indigo-solution on being sus-pended within large bottles holding some oil were completely bleached within a few days. 2. Atmospheric air being entirely excluded the oil when put in contact with pure phosphorus rapidly produced phosphorous acid with some phosphoric acid. 3. The oil on being mixed up with some acetic acid and shaken with minutely divided silver soon produced appreciable quantities of acetate of silver.Heat beingapplied the formation of the acetate was more rapid and abundant. Mercury and copper were likewise oxidized by the oil and transformed into acetates. 4. The oil took up sulphurous acid gas immediately transforming it into sulphuric acid. Aqueous sulphurous acid on being shaken with a suflicient quantity of the oil was likewise turned into sulphuric acid. 5. The oil on being shaken in the cold with a solution of-iodide of potassium assumed a reddish tint whilst the saline solution turned brownish-yellow. On heating and shaking both the liquids together the essence became deep brownish-red from the iodine being elimi- nated and taken up by the oil. Dry bits of ozone test-paper moistened with the oil soon became brown turning dark blue if then plunged in water.The said test- paper being moistened with water and suspended in bottles whose bottom was covered with the oil turned dark blue within the space of a few hours. AND SOME ESSENTIAL OILS. The test-paper iiientioned affords the most convenient means of ascer-taining the presence of the oxidizing principle in ether oil of turpen-tine &c. The deeper the brown or blue colour which the paper acquires on being drenched with the liquids examined the richer are they in the oxidizing matter. 6. A strong solution of pure sulphate of protoxide of iron on being heated and shaken with the essence was very rapidly trans- formed into the basic and acid sulphate of sesquioxide of iron.The same action took place in the cold. I hardly need mention that the protochloride of iron underwent a similar change. 7. The white cyanide of iron above-mentioned on being shaken with the oil turned instantaneously dark blue just as if ozone peroxide of hydrogen bromine chlorine nitrous or nitric acid had been added to the said compound. 8. A nearly colourless solution of the yellow prussiate of potassa on being shaken in the cold with the essence turned deep yellow and was rapidly transformed into the red salt at the boiling-point of water. 9. Minutely divided sulphide of lead suspended in water on being heated and shaken with the oil turned white sulphate of lead being formed. Strips of filtering paper rather strongly coloured by sulphide of lead turned completely white in the cold oil within a couple of honrs and almost instantaneously in the hot essence.Strips of such paper suspended in bottles being covered with the oil were completely bleached within a couple of hours although light was entirely excluded. 10. Minutely divided sulphide of arsenic suspended in water on being heated with the essence rapidly disappeared sulphuric and arsenious acids being formed. 11. A specimen of oil of turpentine capable of destroying thirty- two times its own weight of the strong indigo solution on being heated almost to its boiling point for nearly a quarter of an hour lost 250 per cent of its oxidizing principles. If half the bulk of the same specimen of essence was distilled over this portion of the oil could but destroy the tenth part of its own weight of the standard indigo-solution.This fact proves that heat tends to destroy the oxidizing principle. I must not omit to state that all the specimens of essence of turpentine I have as yet met with in commerce and examined exhibit oxidizing properties but in very different degrees. Some of them were able to destroy not quite the sixth part of their own 138 MR. SCHONBEIN ON A PECULIAR PROPERTY OF ETHER weight of the standard indigo-solution ;others half their weight ; others twice their own weight &c. The specimen of essence cf turpentine to which the preceding statements refer was the richest in the oxidizing matter which T have yet met with being able to discharge the colour of fully thirty-two times its own weight of the standard indigo-solution.I may therefore say that the rates of the oxidizing powers of the two extreme oils examined were as 1 :192. I further found that in all cases the one which had been longest exposed to the action of pure oxygen gas or atmospheric air was found to possess the greatest oxidizing power. III.-OIL OF LEMONS. Numerous experiments made with genuine essence of lemons imported from Sicily proved to me that this oil enjoys to a high degree the power of engendering a powerful oxidizing principle when put in contact with oxygen or atmospheric air ;for with such oil I could produce all the oxidizing effects above mentioned. In examining a variety of specimens of that essence I found that all of them had oxidizing powers more or less according to the length of time during which they had been in contact with the atmospheric air.One specimen I met with in commerce was capable of dis- charging the colour of Z+ times its own weight of the standard indigo-solution. I must not onlit to mention here the curious fact that cork-stoppers having for some time been used to close up bottles containing ether oil of turpentine or essence of lemons appear bleached and attacked in the same manner as if they had been fixed on vessels holding ozone bromine chlorine or nitric acid. It is superfluous to say that the bleaching of those stoppers is due to the same oxidizing agent which according to the preceding statements destroys the colour of indigo &c.; but I must not omit to state that on examining in a commercial house of Bhle in which large stores of essential oils are kept all the cork stoppers closing up the bottles I found many of them strongly bleached and attacked.This makes me almost certain that on further examination besides essence of turpentine and lemons other volatile oils will be found to possess the power of engendering an oxidizing principle on their being put in contact with oxygen. Nay I have reason to believe that even substances very different in chemical constitution from essential oils will behave like essence of turpentine &c. How far light is concerned in the formation of the oxidizing matter above spoken of I do not yet venture to decide.A variety of AND SOME ESSENTIAL OILS. facts make me inclined to believe that light favours very much the generation of that principle. I hope however to be able to speak with certainty about the subject before long. THEOREPXCAL VIEWS ON THE FACTS ABOVE STATED. If I am asked what the oxidizing principle formed inether and the essential oils on their contact with common oxygen is I cannot as yet answer that question otherwise than by conjecture for all my endeavours to insolate that principle have failed. All the substances acting upon it are of an oxidable nature and yield products identical with those which are obtained from the very same oxidable matters on their being subject to the action of ozone. Phosphorus and a number of metals are oxidized sulphurous acid converted iuto sulphuric acid metallic sulphides transformed into sulphates &c.I cannot therefore help conjecturing that the oxidizing principle in question is nothing but oxygen being in that chemically exalted condition in which we know it to exist in ozone. This opinion appears to me to receive an additional support from the fact that ether oil of turpentine &c. on being shaken with strongly ozonized air rapidly take up all the ozone acquiring by that treatment the same oxidiging properties as are gradually developed on putting ether or oil of turpentine in contact with common oxygen. With reference to the question before us it seems to me that the behaviour of guajacum is worthy of our consideration.An alcoholic solution of that matter turns blue on being shaken either with strongly insolated oxygen or ozonized air or a number of metallic peroxides such as that of lead manganese &c. Hence I conclude that blue guajacurn is but a loose compound of the resinoug matter with chemically excited oxygen being comparable to the loose blue compound formed by iodine with starch. According to my former researches it is a fact that the excited oxygen which colours blue guajacum may easilybe taken away again from the resinous matter and transferred to a number of readily oxidable matters such as phosphorus sulphuretted hydrogen sulphurous acid metallic sulphides &c. whence it comes that the matters mentioned have the power of discharging the blue colour of the guajacum so-lution just in the same way as the very same oxidable substances discharge the colour of the aqueous solution of ioduretted starch From the preceding statements it appears that the blue alcoholic solution of guajacum may indeed as to its oxidizing powers be corn ‘OL.1V.-NO. XIV. L 140 MR. SCH~NBEINON A PECULIAR PROPERTY OF ETHER pared to the oil of turpentine &c, which bas for some time been put in contact with common oxygen or atmospheric air. There is another fact to be mentioned bearing upon our ques-tion. The chemically excited oxygen loosely united to guajacum gradually exerts an oxidizing influence upon the oxidable constituent parts of the resinous matter. According to my experiments the solid guajacum as obtained from the dark blue tincture by mixing it up with water preserves for any length of time its blue colour when kept in the shade whilst the same blue guajpcum if dissolved in alcohol gradually loses its colour.Recently prepared tinctured guajacum coloured as deep blue as indigo-solution by the means of peroxide of lead or manganese at the common tem- perature reassumes its original brownish-yellow tint in the course of a few hours. If in the same manner as before that tincture be re-blued then suffered to lose its colour again spontaneously and these colourings and spontaneous discolourings repeated a certain number of times the tincture will at last be chapged so as to become incapable of being blued any more by peroxide of lead or any other means.This fact proves that by the proceedings described the chemical constitution of guajacum is altered no doubt in conse-quence of a gradual oxidizing action produced by the excited oxygen existing in the tincture upon the oxidable constituent parts of the resinous matter. Nopv guajacum being able to form a loose com- pound with chemically excited oxygen why should not ether oil of turpentine and a number of other substances be capable of entering into similar combinations ? and if the excited oxygen loosely associated to guajacum gradually act upon the constituent parts of that resin why should not the excited oxygen stored up in ether oil of turpentine &c. produce oxidizing effects upon these matters and give rise to the formation of carbonic and acetic acids acetic ether resins &c.? As already mentioned I am inclined to think that the excited oxygen contained in the blue tincture of guajacum is in a state of combination similar to that in which iodine exists in ioduretted starch whence it comes that common guajacum dissolved in alcohol is as delicate a test for excited oxygen as paste of starch proves to be €or free iodine. Now as that body is capable of loosely asso- ciating itself not only to starch but to many other organic substances without producing blue-coloured compounds so may excited oxygen enter with many organic matters into loose combinations similar to that which it forms with guajacum without colouring those matters blue AND SOME ESSENTIAL OILS There is another analepy existing between the organic solution of ioduretted starch and the blue tincture of guajacum which in my opinion is worthy of being pointed out here.Both the liquids sponta- iieaasly and gradually discharge their blue colour. Now if the solution of starch be re-b€wd by iodine then suffered to lose its colour again then blued a third time and spontaneously discoloured and so on the dissolved Btareh will at last loge its property of being coloured blue by iodiae. Hence it folbws that the chemical consti- tutiun of gtarch undergoes some change analogous to that suffered by guajacurn. In one case the iodine being loosely associated to stakh disappears hydriodic acid being formed and no doubt some oxidizing action produced upon the oxidable constituent parts d starch; in the other case excited oxygen disappears the guajacum likewise suffering oxidation.Strange as it may sound I do not hesitate to say that I see in both the cases mentioned one and the same action. If I should be requested to give my full opinion about the nature and formation of the oxidizing principle met with in ether the essenees of turpentine lemons &e. it would be as follows. Ether oil of turpentine &c on taking up common oxygen cause (assisted by light) in a manner as yet entirely unknown to us in that body a change of condition similar to that brought about in common oxygen under the influence of phosphorus or electricity. The oxygen thus modified enters into a loose combination with the oil of turpentine &c.and it is only then that the excited oxygen begins to produce real oxidizing effects upon the constituent parts of the organic substames with which it happens to be associated i. e. to engender carbonic acid acetic acid resins Ssc. just as is the case with phosphorus if it be placed in contact with atmospheric oxygen. The first action produced by phosphorus upon common oxygen is to transform the latter into ozone and this work being performed the acidification of phosphorus begins to take place not at the expense of common but of ozonized oxygen; and as under given circumstances phosphorus is capable of producing more ozone than it can take up it becomes by that very behaviour as excellent a means of engendering free ozone as oil of turpentine &c.Under given circumstances more oxygen is brought into its chemicallp exalted condition by the oxidable liquids mentioned than they are able to consume; and hence it comes that on their being placed in contact with common oxygen they are storing up excited oxygen to a great extent. The only difference existing between the two cases of the formation of ozone seems to be this In the first case all the L2 MR. SCH~NBEINON THE PROPERTY OF ETHER ozone formed and not employed for the oxidation of phosphmus is on account of its gaseous state dispersed into the ambient. air whilst in the second case the surplus of the excited oxygen engendered is kept simply dissolved by the essential oils &c.or enters into a loose combination with them. Now if it be a fact that previously to its having been transformed into ozone common oxygen cannot chemically unite even with phos- phorus (at the common temperature) and if it be highly probable that the slow oxidation which ether oil of turpentine &c. undergo at the common temperature is effected not by common but by excited oxygen I think we may be allowed to conjecture that at the common temperature ordinary oxygen as such is not able to combine chemically with any matter and all the slow oxidations are preceded by a transformation of common or inactive oxygen into ozonized or active oxygen The fact that we do not in all cases of slow oxidation perceive that change of condition of the oxygen employed as we do it in that of phosphorus oil of turpentine &c.may possibly be due to a difference in the intensity with which different oxidable matters (capable of undergoing slow oxidation) exert their modifying in- fluences upon common oxygen. Some of those substances may have the power to engender more ozone than they can consume others may produce just as much as they take up or less. As to phosphorus that body may easily be conditioned so as to make it consume all the ozone it engenders in the very moment of its formation. Phosphorus placed within moist atmospheric air will at the freezing point of water or thereabout begin to shine in the dark and be slowly oxidized without yielding however the slightest trace of free ozone as may be easily ascertained by my test-paper.On raising the temperature to about 10' C. the phos- phorus will shine more vividly be oxidized more rapidly and yield free ozone. From this fact we learn that even one and the same body may be slowly oxidized either with or without the appear-ance of free active oxygen. Binoxide of nitrogen is no dou5t the most readily oxidable matter we are acquainted with; for it unites with common oxygen even at very low temperatures to form hyponitric acid. Even in that case I am inclined to believe that previously to its entering into a chemical combination with that binoxide the common oxygen undergoes a change of condition. However that may be it is a fact that the oxygen taken up by the binoxide exists in a condition in which it causes a variety of oxidizing effects very similar to those AND SOME ESSENTIAL OILS.produced by ozone itself. Hence it comes that some years ago several continelitat chemists declared ozone to be nothing but hypo-nitric acid. In concluding this paper I say that if anybody is able to give a better opinion about the facts described in it than mine is I shalt gladly accept and adopt it; for I care very little for my views but a vast deal for truth.

ISSN:1743-6893    

DOI:10.1039/QJ8520400133

出版商:RSC    

年代:1852

数据来源: RSC

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AND SOME ESSENTIAL OILS. XI.-An Analysis of Sediment deposited from the Ever Nile in Lower Egypt. BY MATTHEW ,EsQ., W. JOHNSON OF THE ROYAL COLLEGE OF CHEWISTRY LONDON. The almost proverbial fertility of the Nile valley is usually ascribed to the mud deposited upon the fields after the floods of the River As this substance does not appear to have been hitherto analysed I availed myself of the opportunity afforded me by Dr. Hofmann* of submitting a genuine specimen of the substance collected in the neighbourhood of Cairo to examination. On the qualitative analysis of the sediment the following 5ub- stances were shown to be present viz. sesquioxide of iron alumina lime magnesia potassa soda traces of manganese silicic acid sulphuric acid chlorine carbonic acid traces of phosphoric acid and organic matter.Quantitalive anaZysl:s,-The method followed in this analysis was for the most part that which is usually adopted for the analysis of soils. Without entering into details I may just mention that a general separation was effected by solution in hydrochloric acid and that separate portions of the hydrochloric solution were used for the determination of the individual constituents with the ex- ception of the chlorine. The residue insoluble in hydrochloric acid was fused with carbonate of soda after a special experiment with baryta had proved the absence of appreciable quantities of alkalies. The general course of the analysis becomes sufficiently intelligible * I am indebted to Leonard Horner Esq.F.R.S.,for the specimen in question. Engaged in a series of researches on the geology of the Nile valley Mr. Horner was anxious to know the composition of this deposit in order to compare its constituents with those of the rocks which the river washes on its passage and hadJthe above specimen sent over from a friend residing in Egypt.-A. W. H. MR. JOHNSON ON THE SEDIMENT from the following tables in which I have arranged the experiti.lental numbers. TABLEI.-Behaviour with solvents :-{ inorganic matter . 1.0566 Soluble in water orgal,ic matter . 0*2460 . 93.8438 Insoluble in water {inorganic matter . 4.8542 organic matter 100*0000 Soluble in hydrochloric acid . . 31.6123 . 68.3877 Insoluble residue . . 100-0000 TABLE11.-Quantities of sediment for analysis and wights of the various hydrochloric solutions :-vs.Quantity of air-dried sediment employed for geberal analysis. 146825 Amount of the hydrochloric solution 24303420 Hydrochloric solution for alkalies t 21.2537 Hydrochloric solution for sulphuric acid . . 16.8188 Hydrochloric solution for sesquioxide of iron alu- Exp. I.4S0103 mina lime and magnesia . . .{ , 11.419'290 Hydrochloric solution for sesqdioxide of iron and Ex$ f. 27'9'310 alumina . . , fif. 28.5870' { gxp. I. 1'3:?'600 Hydrochloric solution for sesquioxide of iron . , IT 13,639~ Hydvdchlorid solutiofi for sesquioxide 6f ifon ilnd Exp. I. 13.9710' 0 alumina . , TI. 1&9428@ &$. I. 8*391@ Quantity of air-dried sediment for chlorine ..( , 1%. &13M Qaantity of sedimenb fbr'htd amount of orgaaic {Eky. I. PI9931 m&er . .{ , 11 1*165% Qumitity of sediment fotc total artibunt sbfttble in water . l.-1*2155' Exp. I. 3.4680 buantity of sediment for the carbonic acid . *( , 11. 6.0652 I. 3.2750 Quantity of sediment for total'a'motlrlt of water . 11. 1.1993 ' TABLE rII.-Weights of the various compounds from which the OF ?RE RIVER NILE IN LOWER EGYPT. I45 cbmpositioh of the sediment *as deduced together wi€h that of the insoluble residue :-Residue . . . 9.2597 Mixed chlorides of potassium and sodium . 0,0559 Bichloride of platinum and potassium . 0.0997 Chloride of potassium . 0.0304 Sulphate of baryta for sulphuric acid .. 0.0063 Sesquioxide of iron and alumina . . {EXP I. 0-2166 , If. 0.2155 Sesquioxide of iron Exp. I. 0.1365 ' { , If. 0.1198 Carbonate of lime . {Ikp. 1. 0.1623 , If. 0.1431 Pyrophospsate of magnesia for magnesia . . (Ex& ld. 0*1507 , 11. 0.1225 Exp P. 0-0884 Chloride of silver for chlorine . ' * 1 , 11. 0*0610 Amount of sediment left after ignition . . {ExP* I. 1-0445 , 11 1.0067 Amount of sediment left after exhaustion with water . . 10.2440 Exp. I. 2,0970 Amount of sediaent left after exposure to 120' c. { 1.1065 1 TABLE 1V.-Analysis of the insolhble residue; quantities 6f residue for analysis and weights of the varidus hJtdrocHoric solutions Amount of holubke residue for estimation. No. 1.of silicic acid . 1.9245 Amount of dry origbal sediment fok estihation No. 11. of silicic acid . . . . 1.0237 Amount of insoluble ?&due for the det-emination of sesquioxide of iron and alurriina . . . 1-1710 Insoluble residue for the determination of lime and magnesia . 1.2369 1 Insoluble residue for organic? matter . , 11. 1-1710 Hydrochloric solution for sesquioxide of iron and alumina 30*0019 Hydrochloric solution for sesquioxide of iron . 13.0769 Hydrochloric scilution for lime and magnesia . . 105*4800 Quantity of the above solutiotr for Estimation I of lime and magnesia . . . . . . 442845 0-b s Quantity used €or Estimation If. 39.9553' MR. JOHNSON ON THE SEDIMENT TABLEV,-Weights of the various compounds from which the composition of the insoluble residue was deduced t b {Ey.I. 1.5987 Silicic acid . . 11. 0.5772 Sesquioxide of iron and alumina . . . 0.0589 Quantity of alumina dissolved by treating the fused mass with water 0 . 0*0212 Sesauioxide of iron b b * 0*0147 L Exp. I. OgO166 Carbonate of lime . { , 11. 0.0160 Pyrophosphate of magnesia for magnesia . ' iE;,p* 11' ;::;:; I. 0.6112 Amount of insoluble residue left on ignition { , If 1*14W TABLEV1.-Calculated results of analysis :-Anhydrous sediment per cent. * -56.87 Silicic acid . b Sesquioxide of iron . .--13.119 *-12.1E Alumina . Lime . .-5*43 -Magnesia . *-2.73 Potash .. * .-1-26 Soda . . *-0.89 a 0 .-1 *37 Carbonic acid .. . .-0.27 Chlorine . .-0.22 a Sulphuric acid . -5.53 0-Organic matter . . Traces of phosphoric acid. -Loss 0 . .-0.13 TABLEVI1,-Portion soluble in hydrochloric acid Air-dried sediment Anhydrous -7 sediment. Exp. I. Exp. If. Mean. Sesquioxide of iron 10.5976 10*094!3 10.35 11-22 . 5,9690 6.4723 6.22 6-75 Alumina 3.4986 3.6758 3.59 3-89 Lime . . 2.1154 2*0466 2.08 2.26 Magnesia . OF THE RIVER NILE IN LOWER EGYPT. Air-dried sediment Anhydrous F--h--7 sediment. Exp. I. Exp. TI. Mean. 0 Potassa . . . Exp. I. 1.16 1-26 . Exp. I. 0.82 0.89 Carbonic acid . 1.3.264 1.2035 1.26 1.3'7 Silicic acid . * .Exp. I. 0.70 0.76 . . Exp 1. 0.21 0*%2 Sulphuric acid 0,2598 0*2446 0.25 0.27 Chlorine 3.1019 3.4307 3.27 3.54 Organic matter 7.8240 7*7880 7-78 -Water . Portion insoluble in hydrochloric acid :-Silicic acid . 52*1832 51.2958 51-74! 56.10 . E~P.r. 1.81 1.97 Resquioxide of iron 0 Exp. I. 4.95 5*37 Alumina 0 Lime . . . 1.5753 1.2593 I*42 1-54 Magnesia . 0.4229 0.4433 0.43 0.47 Organic matter . 1.9983 1*66O5 1433 1.99 Loss * 0.13 0-13 100.00 loo'oo In the following table the bases and acids are arranged according to their probable existence in the sediment. TABLEVIIT.-Anhydrous sediment. Portion soluble in hydrochloric acid :-per cent. . 11-22 Sesquioxide of iron . . 6.74 Alumina .. 3.22 Carbonate of Erne . 0.38 Sulphate of lime . 1-99 Lime . . . . . 2.26 Magnesia . Chloride of potassium . . 0.57 Potash . . . 0.90 . 0.89 Soda . a 0.76 Silicic acid . Organic matter . . . 3-54 -32.37 118 MR. JOHNSON ON THE SEDIMENT Insoluble portion :-Silicic acid . 56.10 Alumina . * 5.37 Sesquioxide of iron . 1.97 Lime . . . 1-54 Magnesia . . 0.47 Organic matter . 1-99 s Loss . . . 0.19 -67.63 Soluble portion 32.37 100*00 Provided the specimen examined represents the average composition of these deposits it is diflicult t.0 say from which of the constituents its fertilizing power is derived. Still the great amount of organic matter five and a half per cent cannot be without influence on the processes of vegetation ; and moreover its physical' condition its remarkable state of comminution seems particularly favourable to its absorption by plants.The quantity too of alkalies which is present must exert a highly beneficial action upon their growth. This specimen of sediment was accompanied by several bottles of Nile water ; unfortunately the quantity was too small for a complete analysis I must therehw con'line myself to the fo'Hovt.ing &narks regarding it It possessed a slight odour of sulphuretted hydrogen but failed to blacken acetate of lead. Its taste was soft and it had no reactibn upon litmus-paper. Chloride of calcium and ammonia indicated mere traces of carbonic acid.The qualitative analysis of the residue left on the evaporation of about a pint and a half of .toatel; pointed out the presexice of the following substances sesquioxide of iron lime magnesia soda silicic acid carbonic acid sulphttric acid chlorine and orgdhic matter. The quantity of substance Operated on was too mimike to establish the presence of alumina madganese potassa; ammonia plibifpdoric acid nitric acid apocrenic or crenic acids. On evaporating 494716 grms. of the w&er to i€rynt%s it fur-nished 0.1097 grm. of sblid residue which proved on ignition to contain 0.0310 grm. of organic matter. According to these results an imperial gallon containfs 1.09 grm. or 16.82 pins of solid matter consisting of 0.78 grm. or 12.04grains of inbrganic matter and 0.31 grm.or 4*78gmins of organic matter. OF THE RIV2R NILE IN LOWER EGYPT. 149 Its hardness according to Prof. Clarke’s soap-test metkod was then taken. In six experimenfs the following measures of soaptest! &ere ie-quired to produce on the surface of the ntater a froth that would last five dinutes :-Exp. I. 11. 111. IV. V. TI. Mean. 19-4 19.4 19.6 19.6 19.6 194 195 This corresponds to 9-05 degrees of hardness. APPENDIX. Since reding to the Chemical Society my paper on the Nile Sedimknt I have found that it has been analysed before by Regnault in 1812; Lassaigne 1844; and by M.M. Lajonch&e,-Payen and Poinsot in 1850.* The following table shows the results of their analysis as compared with my own :-Anhydrous sediment Cassaigne. Lajonchkre MM.Payen & Poinsot. Jahnhn. Silit?ic acid . . 47.5 48.9 56.0 56.8 Sestpioxide iron . 15.2 lf2.4 13.6 13.1 Alumiaa-. 23.1 26.5 11.1 12-1 Carb. and Carb. and Carbonate of lime 4.3 4.0 Sulphate 9’8 Sulphlrte 6.9 { Eime. } { xime. } Carb. Maeg. & Mhg. 2.5 2.1 4-1 (Mgo.) a.7 Alkaline chloridee . . 0‘6 0.1 %3 Organic matter . 3.1 5-0 49 55 s Phosphoric acid . . . . traces.

ISSN:1743-6893    

DOI:10.1039/QJ8520400143

出版商:RSC    

年代:1852

数据来源: RSC

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OF THE RIV2R NILE IN LOWER EGYPT. XK-Nottce of a Specimen of Chtorobrornide of SzYver from Chik BY COLONELPHILIPYORTCE, F.R-.S. The specimen to which this notice relates WZLS brought fmm Chili by Vice-Admiral Sir Gedrge Seymour G.C.H. lpt wass ad ir=gda* mass weighing very nearly 601bs. Its general aspect was &at of a red ochraceous substance which here and there contained portions O€ quartz. On clo& examination however the mass was found to be partially. coated,. and hi sewral direCkiOhS traversed by vans of a *' J. Pharm. [33.V 468 and idem XVII 46. COLONEL YORKE ON sectile waxy substance which when cleaned from ochre was nearly black externally but internally of a greenish-yellow colour trans- lucent and crystalline. The veins varied in thickness from $ of an inch to microscopic minuteness.The ochreous matter contained occasionally very small cubic crystals disseminated in it and the coating was in some parts marked by impressions indicating some of the more complicated modifications of the cube. The specific gravity of the sectile substance from a mean of three trials on fragments cleaned as much as possible from adhering foreign matter was found to be= 5*53.* 73.4 grs. of the specimen in fragments accidentally broken off and found in the wrapper were fused with a mixture of the carbon- ates of potash and soda and yielded a button of silver=17*4 grs. The alkaline salts dissolved in water were found by means of solution of chlorine and ether to contain bromine. Phosphoric acid was also detected.ANALYSIS OF THE SECTILE SUBSTANCE The first analysis was attempted according*to the direct method of Fresenius. A fragment weighing 19 grs. was placed on 8 piece of zinc with some water and a few drops-of sulphuric acid; metallic silver was obtained; and by addition of baryta water to the liquid and subsequent evaporation to dryness and treatment with absolute alcohol the saline matter was divided into two portions one soluble and the other insoluble in that menstruum ;these salts then dissolved in water gave by precipitating with nitrate of silver bromide and chloride of silver ;but as a quantitative analysis the results were not satisfactory. A second analysis was made by heating in a porcelain crucible 18.35 grs.of the chlorobromide with a mixture of the carbonates of potash and soda; after keeping the mixture at the point of fusion for some time hot water added dissolved the salts; the remaining silver washed and ignited= 12-28. The alkaline solution was acidified by nitric acid and precipitated by nitrate of silver. The liquid separated from the precipitate was found to contain a trace of copper but on testing for phosphoric acid none was found. The precipitate by nitrate of silver heated to the beginning of fusion in a porcelain crucible weighed 17-33 grs. Of this the * M. Dufrknoy gives the sp. gr. of chlorobromideof silver=4*702. CHLOROBROMIDE OF SILVER. greater part was removed into a bulb reduction-tube for the purpose of subjecting it to heat in a current of dry chlorine gas; but on fusing it and suffering to cool in the glass bulb the latter cracked from the unequal contraction of the glass and the adhering fused salt.The experiment was therefore made by transferring the sub- stance to a little porcelain boat which was enclosed in a tube of hard glass. The chlorine was passed over long after all appearance of the vapour of bromine had ceased. The loss on the 17.33 was then found to be =1.92;and this multiplied by 4.221=8.104,the quantity of bromide of silver in 17.33; or 100 parts would consist of Bromide of silver . . 4643 Chloride I 8 . 53.2 If we adopt the equivalent weights of silver chlorine and bromine determined by Marignac a substance composed according to the formula 3 Ag Cl+2 Ag Br would contain in 100 parts Chloride of silver . . 53.36 Bromide of silver . 46.64 100~00 Calculating the quantities from the silver obtained from 18.35 the result would be Bromide . 8 . 46-3 Chloride . . . 53.7 a This result agrees nearly with one of several analyses of different specimens of Chilian chlorobromide made by M. Domeyko and given by him in his memoir on some of the minerals of Chili published in the Annales des Mines [4] VZ 153.

ISSN:1743-6893    

DOI:10.1039/QJ8520400149

出版商:RSC    

年代:1852

数据来源: RSC

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151 CHLOROBROMIDE OF SILVER. XIII.-On the Tests for Nitrates and a new onefor Nitrites. BY DAVIDS. PRICE,Yh.D. F.C.S. My attention having been directed to the detection of nitric acid in cases where if it existed at all its quantity could be but small 1 deemed it necessary as a preliminary step to ascertain the merits of some of the tests usually adopted for that purpose. The experintents were confined chiefly to two rcactious generally considered the most DR. PRICE ON THE TESTS FOR NITRATES susceptible for nitrates; the one where the indication of the presence of nitric acid is the production of a dark violet or brown colour caused by adding a solution of protosulphate of iron and concentrated sulphuric acid to a solution of a nitrate; the other where it is the destructive action of nitric acid on indigo the solution of the nitrate being made slightly acid with sulphuric acid and then a solution of sulphate of indigo added.Before however detailing the results I have arrived at with respect to these tests I shall proceed to describe a new one that has suggested itself for nitrites but which admits under certain cir- cumstances of application also for the detection of nitrates Thinking that the addition of dilute hydrochloric acid to a solution of a nitrate in presence of iodide of potassium and starch-paste might cause the chlorine thus liberated to act in the nascent state on the iodide and so produce the well-known blue colour I tried the experiment and found it to answer apparently most successfully.I was however surprised to find that of several nitrates employed that of potassa was the only one with which the experiment succeeded ;furthermore that hydrochloric acid was not at all a necessary condition for the production of the blue colour oxalic dilute sulphuric and even diluted nitric acids effecting the same whilst the same diluted acids produced no change in a simple mixture of iodide of potassium and starch-paste. It was therefore evident that the action was not dependent on chlorine but on some substance to be found in nitrate of potassa and which will be demonstrated by the following experi- men ts. On distilling a few grains of nitre dissolved in five ounces of water wth a small quantity of concentrated sulphuric acid a distillate was obtained of slightly acid reaction which when neutralised with carbonate of potassa and concentrated and then added to a mixture 04 iodide of potassium starch-paste and dilute hydrochloric acid was found to produce a much deeper blue colour than did a conceiitrated solution of the original nitrate.This led me to try the effect of the xiitrites on the same test-mixture and which I found to possess the property of liberating iodine under the circumstances described in a nlost remarkable degree and which must be attributed to the reduction of hydriodic acid by nitrous acid. On subjecting the nitrate of potassa employed for the foregoing experiments to re-crystallisation the crystals then obtained were found to have entirely lost the property they originally possessed whilst the mother-liquor rcktained it in a high degree clearly showing that the peculiar action of the nitrate of potassa was to be attributed to the presence of a small qiiantity of nitrite.It has been shown that a very distinct indication of AND A NEW ONE FOS NITRITES. nitrous acid was obtained in the distillate from ordinary nitre and sul-phuric acid; in arder to see if such would be the case with small quaxltities of pure nitre when tEeated with pure sulphuric acid I re-peated the experiment employing two grains of the pure sdt six ounces of water and half an ounce of concentrated sulphuric acid when after treating the distillate in tbe wanner before described abundant proof was afforded of tbe presence of nitrous acid.In aJ1 cases therefore where distillation is necegsary in searching for nitrates this test way he indirectly applied for thew. Those substwces which intexfere with tbe formation of iodide of starch under ordinary circumstances prevent its pro,cluction alvo by the present test. The method of employing the test is the folJowing A few drops of a dilute aquecrug solution of iodide of potassium (free from iodate) are mixed with a little Starch-paste and then dilute hydrochloric acid of sp. gr. 1006 added. The liquid suspected to contain a nitrite if alkaline must be slightly acidified with hydrochloric acid and then added to the te$t-mi)rture when ifmu& nitrite be present a dark-blue colour will he i~sta~tily produced; and if very small traces only then the liquid first assurpes a pale fawn colour which grad,ually chqnges to that of violet plum md ultimately dark-blue.The extraordinary delicacy of the test will be seen from the following experiments. When water cOntaining only the &th part of nitrous acid (as nitrite of soda NaO NOO,) is added to t4e test-mixture a violet colour is almost instantly produced; with the &th part the colour makes its appearance in a few seconds; with the +th part after the lapse of two or three minutes; with the &th part a change may be ob-served in twelve minutes apd with the ydEth part a violet tint is produced in about fifteen minutes. In all these cases the liquid rapidly assumes a dark-blue colour. By performiirg the experiments in a porcelain basin the faintest indication of colour may be ob-served.In searching for minute traces in a very large bulk of liqilid it is advisable to add more iodide of potassium than where the volume of the liquid is small. Since performing these egperirnents T find that Schonbein* has noticed the action of nitrites on iodide of potassium. With respect to the tests for nitrates specified at the commence- merit ofthe paper De Richemontf- has found that by the ernploy- meat of the first one he was able to detect the $=tb part of nitric acid in q solution. The one by means of indigo has had narrower limits assigaed to it; Lie bigf who suggested it states that the &th * J. Pr. Chem. XLV 227. -1. Graham’s Chemistry 297. Cmeiin’s EIaiidbuch cler Chemie I 813.DR. PRICE ON THE TESTS FOR NITRATES part of nitric acid may be recognised by it and the &th part when a little chloride of sodium is added. I shall endeavour to show that in both cases the action is in all probability due to nitrous acid contained either originally in the substance as nitrite or produced by the action of sulphuric acid upon the nitrate; at any rate that nitric acid in the cold has no apparent action upon either of them. And first as regards the test with sulphate of protoxide of iron. If sulphuric acid be added to a solution of nitrate of potassa free from all nitrite and briskly agitated with it so as to prevent the mixture from becoming heated and then a. solution of sulphate of protoxide of iron added no change whatever in the colour of the liquid will ensue even when allowed to stand for some time which could not be the case did the action of the test depend on nitric acid.If to the same mixture one drop of a dilute soltion of nitrite of potassa be added a brownish colour will be immediately produced showing the instantaneous effect of nitrous acid upon the test. If instead of keeping the mixture of nitrate of potassa and sulphuric acid cold we gently warm it and then add a solution of protosulphate of iron and a few drops more of concentrated sulphuric acid a dark-violet colour will immediately appear accompanied be an energetic disen- gagement of gas; the colour in this case soon disappears owing to the heat evolved but can readily be reinstated by a fresh additioii of the protosulphate of iron.Or again if we first add a solution of protosulphate of iron to the solution of the nitrate and theu pour in the concentrated sulphuric acid in such a manner that it 'forms a layer at the bottom of the vessel we shall find that a violet colour will be produced at the contact-surface of the two liquids; the heat in this as in the former case being sufficient to cause the formation of nitrous acid. In searching therefore for small quan- tities of nitrates it is advisable to add as recommended by De Richemont a large bulk of concentrated sulphuric acid. With respect to the delicacy of this test for nitrites I have found that a liquid containing the &th part of nitrous acid (in the form of a soda-salt) becomes immediately coloured green upon the addition of a small quantity of sulphnric acid and sulphate of iron; that perceptible shades of green are produced when a liquid contains the &kth and a faint colorisation with the T;$th part.In like manner to the preceding test I have found that a solution of pure nitrate of potassa which has been treated in the cold with concentrated sulphuric acid or decomposed with tartaric acid has no action whatever upon a solution of sulphate of indigo but that the presence of the smallest quantity of nitrous acid is sufficient to destroy the same. By applying heat to the mixture of sulphuric acid AND A NEW ONE FOR NITRITES. and solution of nitre to which a few drops of indigo-solution have been added the colour of the latter will be found rapidly to vanish and the test then becomes an exceedingly delicate one for nitrates and in the absence of chlorates and organic matter may be most advantageously employed for them.I have exanlined the delicacy of the test for nitrites and have found that the one two and three millionth part of nitrous acid in a solution may be detected by means of it. By all the foregoing tests it will be found that the siilphuric acid of commerce as well as most kinds of carbonate of potassa contain a trace of nitrous acid. In conclusion I may state that I have applied the nitrites to the detection of the iodides the results of which experiments will be found in the accompanying communi- cation.

ISSN:1743-6893    

DOI:10.1039/QJ8520400151

出版商:RSC    

年代:1852

数据来源: RSC

摘要:

AND A NEW ONE FOR NITRITES. XIV.-On u New Test for Iodides. BY DAVIDS. PRICE,Yh.D. F.C.S. Having in the preceding paper pointed out the principle on which the detection of nitrites by means of iodide of potassiurn and hydro. chloric acid depends I shall proceed briefly to describe the appli- cation of nitrites for the detection of iodides and at the same time give one or two instances of the practical application of the test in cases where the quantity of iodine is exceedingly small. The method of employing the test is the following. The liquid suspected to contain an iodide is mixed with starch-paste and acidified with hydrochloric acid a solution of nitrite of potassa is then added when if much iodine be present a dark-blue colour will be instantly produced; if a very small quantity only as for instance the two or three millionth part then a few seconds elapse before the blue colour makes its appearance.In this manner I have detected the &th part of iodine dissolved in water as iodide of potassium. It will be seen that the test admits of a degree of delicacy not attainable by any of the other methods for detecting iodides as well as being at the same time free from the disadvantages to which they are more or less subject; as for instance in the employment of chlorine which unless added very carefully to a liquid containing a trace of an iodide only is almost sure to afford a negative result from the chlorine combining with the iodine and so preventing its acting on the starch. The same error may also VOL IVe-NO.XIV. M DR. PRICE ON A NEW TEST FOR IODIDES. arise by the use of nitric acid should the suspected liquid contain a large amount of chlorides. I will now detail the two cases in which I have applied this test in the one for the purpose of detecting iodine in cod-liver oil the object being to see how small a quantity of the oil would suffice; in the other for the purpose of detecting iodine in marine vegetation. One ounce of' ordinary brown cod-liver oil was saponified by a concentrated solution of caustic potash and then carbonised in an iron spoon over an open fire j the residue was removed into a covered porcelain crucible and strongly heated so as effectually to destroy all organic matter and when cold was digested with a small quantity of water and thrown upon a filter ; the filtrate being acidified with hydrochloric acid was then mixed with starch-paste and tested with nitrite of potassa which almost immediately pro-duced a pale plum colour.Sea-water contains so small an amount of iodine that it is ex-ceedingly difficult to detect even a trace of it in the mother-liquor from several pounds of water. Minute as this quantity must be it is nevertheless collected and assimilated by many marine plants and the following experiment enables us to demonstrate its presence in their juices. If we take a thin transverse sectional slice of the stem of the Fucus laminaria digitata moisten it with a little starch-paste and dilute hydrochloric acid and examine it by the aid of the microscope we shall upon adding a drop of a solution of nitrite of potassa to the same be able most distinctly to observe the formation of iodide of starch.The presence of an iodide may be shown in a still more marked manner by suspending the stem of the same plant in a dry atmosphere when the surface after the lapse of some hours or days will become covered with numerous transparent crystals which on examination will be found to consist principally of chlorides but at the same time to contain so much of an iodine-compound as to impart an intense blue colour to the test-mixture. Many marine plants when placed in a fresh state in contact with the test-mixture impart an orange colour to it owing to the liberation of bromine.

ISSN:1743-6893    

DOI:10.1039/QJ8520400155

出版商:RSC    

年代:1852

数据来源: RSC

摘要:

DR. PRICE ON A NEW TEST FOR IODIDES. XV.-OObservations on the Teas of Commerce. BY R. WARTNGTON, F.C.S. In my previous communication to the Society on this subject in February 1844,* I endeavoured to slzow that there exist two distinct * Memoirs and Proceedings of the Chemical Society 11 73. MR. WARINGTON ON THE TEAS OF COMMERCE. 157 kinds of green tea known in commerce asglazed and unglazed; that the former is coloured by the Chinese with a mixture of Prussian blue and gypsum to which a yellow vegetable colouring matter is sometimes added while the latter are merely dusted with a small quantity of gypsum; that in the specimen of the so-called Canton gunpowder this glazing or facing is carried to the maximum. I also mentioned that I had never met with a sample of green tea in which the blue tint was given by means of indigo.Since the publication of that paper I have been in communication with several parties of great experience in this subject from whom I have received much additional information which with several ex-perimental points of interest that have come under my own immediate observation will form the subject of the present paper. The first point to which I wish to call the attention of the Society is the question of the blue colouring matter used by the Chinese for colouring the green teas being Prussian blue because some doubts have been thrown on this subject from various quarters. Mr. Bruce thus states:* “ The Chinese call the former (the Indigo) Youngtin the latter (the sulphate of lime) ACCO.” Now I’ am favoured with the opinion of Mr J.Reeves on tbis point whose knowledge and experience render him most competent to decide in such a case j he believes that indigo is never employed for coloriring used on tea that the term Youngtin as used by Bfr. Bruce should be Yong-teen foreign blue the name given by the Chinese to Prussian blue in contra-distinction to Too-teen native blue or indigo; this I think is very conclusive evidence and shows that Mr. Bruce’s statement was erroneous. In another quarter a surmise has also been published on this same point. Mr. Fortune in his entertaining work? on China says speaking of the ingredients used in dying the Northern green teas for the foreign market p. 201 ‘‘There is a vegetable dye obtained from Tsaris Indiyotica much used in the northern districts and called Tein-ching and it is not unlikely that it may he the substance which is employed;” again at p.307 “ I am very much inclined to believe that this (the Tein-ching) is the dye used to colour the green teas which are manufactured in the north of China for the English and American markets.” This question however I think is now satis- factorily settled and the experimental evidence I had adduced of the material being Prussian blue of a darker or paler tint placed beyond a doubt by a positive demonstration ;for Mr. Fortune has forwarded * Report on the Manufacture of Teas &c. by C. A. Bruce Aug. 16,1839. -f Three Years’ Wanderings in the Northern Provinces of China by Robt.Fortune. M2 MR. WARINGTON ON from the north of China for the Industrial Exhibition specimens of these materials which from their appearaim there can be no hesita- tion in stating are fibrous gypsum (calcined) turmeric root and Prussian blue; the latter of a bright pale tint most likely from admixture with alumina or porcelain-clay 11hich admixture may account for the alumina and silica found as stated in my previous paper and the presence of which mas then attributed possibly to the employment of kaolin or agalmatolite. Mr. J. R. Reeves in a letter to my friend Mr. Thompson dated July I 1844 commenting on niy paper says (c hfr. Warington’s experiments have led him to correct results as to the substances used which I know to be Yrussian blue gypsum (fibrous) and turmeric ;the second being sulphate of lime; and the last the ‘yellow or orange-coloured vegetable substance,’ which Mr.W. does not otherwise name. That the colouring is not intended as an adulteration I feel quite sure. It is given to suit the capricious taste of the foreign buyers who judge of an article used as a driizk by the eye instead of the palate. You well know bow little the Loiidon dealers even now like the yellowish appearance of uncoloured green tea. The Americans a few years since carried the dislike even further than the English and therefore the Chinese merchant had scarcely a chance of selling his tea unless he gave it a ‘face’ that would suit their fancy. The small quantity of the colouring matter used must preclude the ides of adulteration as a matter of profit.” hlr.J. Reeves states ‘(that in the East India Conipany’s time gypsum and Yrussian blue were sometimes used upon hyson teas Tien Hing using the first on his pale bright hyson ; Lum Hing the latter on his dark bright leaf; but these were only in minute quantities just sufticient to produce an uniform face.” It is still a question of interest which I before alluded to whether the gypsum in its calcined state is not used for the absorption of the last portions of moisture and allowing the tea the better to with- stand the damp of the sea voyage. Through the kindness of Dr. Koyle I have received since my last communication a sample of green tea from the Kemaon district in the Himalayas which is quite free from any facing as are also the green teas of Java a large number of which I have had the opportunity of examining and which are exceedingly clean and genuine in their appearance and characters.ON BLACK AND GREEN TEAS. Although the preparation of green andblack tea from the respective THE TEAS OF COMMERCE. .plants the Thea Viridis and the Thea Bohea has been warmly advocated by many botanists yet it is now I believe pretty generally admitted by all parties that both green and black teas can be and are made indiscriminately from the same parcel of leaves taken from the same species of plant. It is also well known to all persons that the iiifusions from these teas have rnarlced differences of colour and of flavour and that the effects produced on some constitutions by green tea such as nervous irritability sleeplessness &c.are very distinct from those of black tea. Their characteristic physical differences are too well known to require any comment but they have peculiar chemical properties to which we shall have occasion to allude more particularly presently and which have always been attributed by chemists to the effect of high heat in the process of manufacture. The question presents itself then-from whence do these distinguish- ing peculiarities arise and to what are they to be attributed ? From observations made in other directions in the course of the routine work of the establishment to which I an1 attached I had formed in my own mind certain conclusions on this subject.I allude to the exsiccation of medicinal herbs ;these are for the most part nitro- genous plants as the Atropa belladonnu the Wyoscyamus niger the Coniurn maculatum and others. The plants are brought to us by the growers or collectors from the country tied up in bundles and when they arrive fresh and cool they dry of a good bright green colour; but on the contrary it is found that if they are delayed in their transit or remain in a confined state for too 10~g a period they become heated from a species of spontaneous fermentation and when loosened aiid spread open emit vapours aiid are sensibly warm to the hand; when such plants are dried the whole of the green colour is found to have been destroyed and a red-brown and sometimes a blackish-brown result is obtained.I had also noticed that a clear infusion of such lcaves evaporated carefully to dryness was not all undissolved by water but left a quantity of brown oxidised extractive matter to which the denomination Apofheize has been applied by some chemists; a siniilar result is obtained by the evaporation of an infusion of black tea. The same action takes place by the exposure of the infusions of many vegetable substances to the oxidising influence of the atmosphere ;they become darkened on the surface and this gradually spreads through the solution and on evaporation the same oxidised extractive matter will remain insoluble in water. Again I had found that the green teas when wettedand re-dried with exposure to the air were nearly as dark in colour as the ordinary black teas From these observations therefore I wits I60 MR.WARINGTON ON induced to believe that the peculiar characters and chemical differences which distinguish black tea from green were to be attributed to a species of heating or fermentation accompanied with oxidation by exposure to the air and not to its being submitted to a higher tempe- rature in the process of drying as had been generally concluded. My opinion was partly confirmed by ascertaining from parties conversant with the Chinese manufacture that the leaves for the black teas were always allowed to remain exposed to the air in mass for some time before they were roasted. Mr. Ball in his valuable work,* on the manuf,icture of tea has described in detail the whole routine of these interesting processes fully confirming my preconceived opinions and of which I cannot do better than give you a summary.Some of the facts I believe had been published in Batavia in 1844 by Mr. Jacobson,? in the Dutch language. In the preface to his work Mr. Ball says I‘ It will be seen by dates incidentally adverted to that the facts and most of the materials of this work were established and collected thirty years ago.”-“These facts as well as other materials were derived from conversation with growers and manipu- lators from the tea districts; from written documents furnished by Chinese ; from published works in the same language diligently sought out ; and also from correspondence with a Spanish missionary long resident in the province of Fokim.These were all put into their present forin full twenty years ago and were read to one or two friends during my residence in China.”-“ They were not however so arranged with any view to immediate publication.”-“ They were thus disposed as the best mode of recording and keeping together the facts and materials I had collected.”-“ But it was not till the year 1844 when I received Mr. Jacobson’s Handbook on the cultivation of tea in Java that I found my own views so far confirmed and my information such as to justify me in bringing my labours to a close.” The processes peculiar to the preparation of black tea are styled Leang-Ching To-Ching and Oc-Ching and these all consist in carefully watched and regulated processes of spontaneous heating or slow fermentation of the leaves until a certain degree of fragrance is developed.Theleavcs are said to wither andgive and become soft and placid. The utmost care p,ractical skill and experience is re-quired in the properly conducting these operations and as soon as the proper point is arrived at the leaves are to be immediately removed * An Account of the Cultivation and Manufacture of Tea in China by S aml. Ball Esq. -p Handboek v. d. Kult. en Fabrik v. Thee. THE TEAS OF COMMERCE. I61 to the Kuo or roasting-pan. After being roasted and rolled two or three times they are then to be dried and this is effected in the Poey-long which consists of a cylinder of basket-work open at both ends and covered on the oirtside with paper ; it is about %ifeet in height and 14 in diameter which diameter is diminished in the centre like an ordinary dice-box to one foot and a quarter.This stands over and round a small charcoal fire and is supplied with cross-bars about fourteen inches above the fire on which an open sieve containing the tea is placed; and a small aperture about an inch and a half in diameter is made in the centreof the tea with the hand so that an ascending current of air and the products of the combustion pass through and over the tea contained in the sieve. A circular flat bamboo tray is placed partially over the niouth of this cylindcr and most probably serves to regulate the rapidity of the ascending current prevent the admission of the cold air to the leaves and at the same time allow a sufficient outlet for the generated watery vapours and the products of combustion.At the commencement of this operation the moist leaves are still green and retain their vegetable appearance ; after the drying has continued about half an hour the leaves are turned and again submitted to the heat for another half-hour; they are then taken out rubbed and twisted and after sifting away the small dust again returned to the sieve and drying tube. This operation of sifting is very neccssary to remove any of the small tea or dust which might otherwise fall through the meshes of the sieve on to the fire and the products of their combustion would deteriorate and spoil the flavour of the tea.The leaves have now begun to assume their black colour ; the fire is diminished or deadened by ashes; and the operation of rolling twisting and sifting is repeated once or twice until they have become quite black in colour well twisted and perfectly dry and crisp. They are then picked winnowed and placed in large quantities over a very slow fire for about two hours the cylinder being closed. NOW, that this black colour is not owing to the fire is evident; for in cases mentioned by Mr. Ball where the leaves have been dried in the sun the same colour is obtained ;and on the other side if roasted first without the process of fermentation or withering and then finished in the Poey-long a kind of green tea is produced. In the operations for the manufacture of green tea on the contrary the freshly-picked leaves are roasted in the Kuo at once without delay at a high temperature'; rolled and roasted again and again assisted sometimes with a fanning operation to drive off the moisture ; and always with brisk agitation until the drying is completed.SIR. WARIXGTON ON The marked differences in the mode of manufacture of black and green tea will I consider after what has been stated fully account for all the variation of physical and chemical prcperties to which I have before alluded. ADULTERATION AND SOPHISTICATION OF TEAS. Since writing niy former paper several teas have come under my notice which must be elwed under this head. The first I shall mention is a sophistieation whir% has been carried on in this country to some extent and consists in giving the appearance of green tea to an imported black tea.The material used as the bodies for this process of manufacture is a tea called scented caper; it is a small closely-rolled black tea about the size of small gunpowder and when colowed is vended under this latter denomination the difference in price between the scented caper and this fictitious gunpowder being about 1s.per lb. a margin sufficient to induce the fraud. This manu- facture has been carried on I understand at Manchester and was kept as secret as possible; and it was only after considerable trouble that some of my friends succeeded in obtaining two different speci- m'ens for me that could be fully depended OD as originating in this manufactory.It appears that it is generally mixed with other tea so as to deceive the parties testing it. IIow this manufacture was conducted I am not prepared to say; but some preparation of copper must have been eniployed as the presence of that metal is readily detected in the specimens 1 received. I believe however that this sophistication has ceased. I have now to call your attention to another adulteration of the most flagrant kind. Two samples of tea a black and a green were lately put into my hands by a merchant for examination the results of which he has allowed me to make public. The black tea was styled scented caper; the green gzcnpowder; and I understand they are usually imported into this country in small chests called catty pack- ages.The appearance of these teas is remarkable ; they are appa-rently exceedingly closely rolled and very heavy ;the reasons for which will be clearly demonstrated. They possess a very fragrant odour. The black tea is in compact granules like shot of varying size and presenting a fine glossy lustre of a rery black hue. The green is also granular and compact and presents a bright pale-bluish aspect with a shade of green and so highly glaxed and faced that the facing rises in clouds of dust when it is agitated or poured from one vessel to another ; it even coats the vessels or paper on which it may be poured. On examining these samples in the manner described in THE TEAS OF COMMERCE. my former paper. to remove this facing I was struck by the tenacity with which it adhered to the surface and which I had never re-marked in any previous sample requiring to be soaked for some time in the water before it could be detached; with this precaution how- ever the greater part of the facing material was removed.It proved in the case of the sample of green tea to be a pale Yrussian blue. a yellow vegetable colour which we now know to bc turmeric and a very large proportion of sulphate of lime. The facing from the sample of black tea was perfectly black in colour and on examina- tion was found to coilsist of earthy graphite or black lead. It was observed that during the prolonged soaking operation to which these teas had been submitted there was no tendency exhibited in either case to unroll or expand for a reasou which will be presently obvious.One of the samples was therefore treated with hot water without however any portion of a leaf being rendered apparent. It increased in size slightly was disintegrated and then it was found that a large quantity of sand and dirt had subsided; this was sepa- rated by decantation and collected; it was found to amount to 1.5 grains from 10 grains of the sample or 15 in the 100 parts. It was evident however that much of the lighter particles must neces- sarily have been lost in the process of decantation; a weighed quan- tity of the sample was therefore carefully calcined until the ash was quite white and the whole of the carbonaceous matter burnt off it yielded a result equivalent to 37.5 on the 100 parts.During this operation also no expansion or uncurling of the leaf as is generally to be observed when heat is applied to a genuine tea was seen; in fact it was quite evident that there was no leaf to uncurl the whole of the tea being in the form of dust. The question next presented itself as to how these materials had been held together and this was readily solved; for on examining the infusion resulting from the original soaking of the sample abundant evidence of gum was exhibited. The sample of green tea was of a precisely similar kind to the black; it yielded 4.55 grains of ash &c. from 10 grains of the specimen or 45.5 per cent. A specimen of Java gunpowder yielded 5 per cent of ash; so that we have in this sample 40% per cent of dirt and sand over and above the weight of ash yielded by the inci-neration of a genuine tea.Thus we have then in these samples a mixture of tea-dust with dirt and sand. agglutinated into a mass with a gummy matter most probably manufactured from *rice-flour then formed into granules of the desired size and lastly dried and coloured according to the kind required by the manufacturer either with black lead if for black tea; or with Prussian blue gypsum or turmeric if intended for green. 164 MR. WARINGTON ON THE TEAS OF COMMERCE. Since examining these two samples I have obtained through a friend another specimen of green tea having a very different appear- ance; that is better manufactured or rather I should say more likely to deceive the consumer from its being made to imitate an unglazed tea.It is of a yellowish-green colour scented and granu- lated as the former samples and not much dusted; it yielded 34 per cent of ash sand and dirt. On inquiry I have learnt that about 750,000Ibs. weight of these teas have been imported into this country within the last eighteen months their introduction being quite of modern origin; and I understand that attempts have been made to get them passed through the Customs as manufacturedgood8,and not as teas ;a title which they certainly richly merit although it must be evident from a moment’s consideration that the revenue would doubtless be defrauded inasmuch as the consumer would have to buy them as teas from the dealer.It is to be feared however that a market for them is found elsewhere. The Chinese it appears will not sell them except as teas and have the candour to specify them as lie teas; and if they are mixed with other teas of low quality the Chinese merchant gives a certificate stating the proportion of the lie ka present with the genuine leaf. This manufacture and mixing is evidently practised to meet the price of the English merchant. In the case of the above samples the black is called by the Chinese lie flower caper; the green lie gun-powder; the average value is from 8d. to 1s. per lb. The brokers have adopted the curious term gum and dust as applied to these lie teas or their mixtures a cognomen which at first I had some dif&ulty in understanding from the rapid manner in which the two first words were run together.f may subjoin the results obtained from the carefd incineration of a variety of teas as they may be interesting for the purpose of com-parison and illustrate the point I have mentioned as to these spurious teas being mixed with genuine ones. Gunpowder tea made in Java gave 5.0 grains of ash in the 100parts; Gunpowder during the East India Company’s Charter . 5.0 Kemaon hyson . . . 6.5 Assam hyson . . . 6.0 Lie gunpowder No. I . 45.5 Y9 No.2 . . 34.0 Scented caper . Lie flower caper . . . 5.5 . 37.5 92 12 No.2 Mixtures containing these lie teas No. 1 . . 11.0 . 22.5

ISSN:1743-6893    

DOI:10.1039/QJ8520400156

出版商:RSC    

年代:1852

数据来源: RSC

摘要:

MR. J. A. PHILLIPS ON THE CARBONATCS OF LEAD. 165 XVL-On the Composition and Properties of the Carbonates of Lead comtituting the White Lead of Commerce. BY J. ARTHUR F.C.S. PHILLIPS Having had occasion to devote considerable attention to the manufacture of commercial white lead by the old Dutch method I have in order to better understand the principles on which this process depends been induced to undertake a numerous aeries of experiments on the physical and chemical properties of various specimens of this substance prepared both by the ordinary process of slow corrosion and also by precipitation from the salts of lead by the carbonated alkalies. Many of the results obtained during these investigations being merely of a practical nature and consequently of but little interest to the scientific chemist have been omitted in tlie present paper in which I shall chiefly confine myself to an examination of the coin- position of the carbonates of lead used as pipents and of the several temperatures at which they undergo decomposition.On referring to the analyses of this substance which have from time to time been published in the scientific journals very considerable differences in the results obtained by the authors of the various papers cannot but be remarked. In some instances also no mention is made of the temperature to which the substance was exposed pre- vious to analysis ;but having been led to believe that this circumstance alone might be sufficient to account for many of the differences above referred to I have in my own experiments paid especial attention to this subject On subjecting portions of hard dry lead fresh from the tan beds to the desiccating influence of sulphuric acid under the exhausted receiver of an air pump until they ceased to lose weight I have invariably found that the loss sustained amounted to about 0.001 of the total quantity of the substance used.If the salt which has been thus treated be taken from beneath the exhausted receiver and afterwards exposed in a steam-bath for several successive days to a temperature of 212' Fahr. no further diniinn- tion of weight will in any case be found to occur ;and as this tcmpe- rature may even be increased to 220' withoat further affecting the weight of the salt operatd on I have assumed that the water which this substance retains when so treated is in chemical combi- nation and forms an essential ingredient of ordinary white lead.VOL. IV.-NO. XIV. M3 MR. J. A. PHILLIPS ON In order to ascertain the exact composition of this compound a known quantity was after drying at 212' until it ceased to lose weight introduced into a bulb blown in a tube of hard glass through which a current of pure dry air was made to pass. This bulb was afterwards heated to redness for the purpose of expelling the car- bonic acid and water of which the former was collected and weighed in a Liebig's potash apparatus and lhe latter in a chloride of calcium tube. The accompanying figure will serve to explain the nature of the apparatus employed and the different precautions taken to prevent error in the results obtained.FIG. 1. The tube a which is firmly fitted by means of a perforated cork to the bulb-tube b is filled with caustic potash broken into sniall pieces and slightly plugged at its two extremities with pieces of cotton wool to prevent any particles of potash from being mechani- cally drawn into h and vitiating the results obtained. The other extremity of the tube 6,which is of hard German glass and in which the white lead to be analysed is placed is connected by another perforated cork with the chloride of calcium tube c which is itself united by a caoutchouc connector with the Liebig's apparatus d. To the potash bulbs succeeds a second chloride of calciiirn tube e which is joined by connectors and a long glass tube fJ to the aspirator g by means of which a current of air may be readily drawn through the whole airangement.To rnalce an analysis with this apparatus the tube 6 closed with two accurately-fittiiig corks is first weighed when empty. A quantity of the substance to be examined is now introduced into the bulb and the end being again closed with the corks before employed the whole is re-weighed and the difference between the two weighings evidently corresponds to the quantity of white lead which it contains. The THE CARBONATES OF LEAD. 167 tube and its contents are then placed on two iron hooks i i and the weights of the tubes c and e afterwards taken and noted as well as those of the potash apparatus d and the whole of the arrangement is put together and tied to the frame I as shown in the figure.The potash apparatus is now placed in an inclined position by means of the strings h and by closing up the orifice a’ and at the same time turning the tap g’ the tightness of the various joints and corks is readily tested. Should the current of water which at first issues from the tap rapidly diminish in volume and subsequently cease altogether it shows the arrangement to be air-tight and the experiment may be at once proceeded with. For this purpose the opening a’ is uncorked and the tap g’ so turned as to allow the water to escape in slow successive drops. The current of air wbich is thus drawn through the apparatus will in passing through the tube a lose both its moisture and carbonic acid and consequently arrive in the tube b in a pure and perfectly dry state.The flame of a spirit-lamp or gas jet is now cautiously applied to the bulb which is by slow dcgrees heated to bright redness. A short time after the application of the flame a certain amount of water is observed to pass into the ttrbe c and continues to do so until the substance becomes nearly red-hot. At the expiration of half an hour the operation will be completed and after being allowed to cool the various tubes are closed with proper corks and weighed. The excess of weight on the tubes c and e and potash apparatus d should exactly correspond to the loss sustained by b. The increase of weight on c represents the amount of water found and that on the united weights on d and e the quantity of carbonic acid present.* The following results were obtained by the analysis of different varieties of hard lead taken directly from the bed and subsequently heated to 21ZoFahr.until no further loss of weight was observed. TV. BLACKETT LEAD. PIRST ANALYSIS. Weight operated on = 32.94grs. Weight of carbonic acid found = 3.71 grs. = 11.26 p. c. , oxide of lead . = -28*50 , = 86.52 , _. , water . . --T4 , -2.24 , 32.95 100.02 * The employment of the tube e becomes necessary on account of the quantity of moisture carried off by the dry air from the potabh apparatus. This in most instances amounted in my experiments to about 0.20 grs. in each operation.MR. J. A. PHILLIPS ON SECOND ANALYSIS. Weight operated on = 22.46 grs. Weight of carbonic acid found = 2.53 grs. oxide of lead . = 19-43 ), ?> -> water . --50 , 22.46 The above results may be thus expressed I. Carbonate of lead * . 6853 . 29.23 Oxide of lead . . 2.24 Water . -__I 100*00 DARLINGTON LEAD. FIRST ANALYSIS. Weight operated on = 15-26 grs. Weight of carbonic acid found = 1.79 grs. , oxide of lead = -13.16 , , water . *-*32 , c_- 15.27 SECOND ANALYSIS. Weight operated on = 20.23 grs. Weight of carbonic acid found = , oxide of lead . = -, water . *-or 2-33grs. 17.50 , *41 ,Y 20.24 1. Carbonate of lead = 71.29 Oxide of lead = 26.67 Water .. -2.09 100.05 = 11.26 p. c = 86-51 ,, --2.23 , I-1oo*oo 11. 68.43 29.34 2.23 P 100~00 = 11.73 p. c. = 86.23 ,, -2.09 , 100*05 = 1lo52p.c. = 86-50 ,, -2-02) 100.04 11. 70.00 28.02 2-02 100.04 The specimens of white lead of which the composition is above given were extremely hard and firm; but in some of the corrosions THE CARBONATES OF LEAD. by the Dutch process a peculiarly soft spongy variety is obtained which crumbles under the touch and has a remarkable effloresced appearance. This lead is much less dense than that ordinarily made and the coating formed on the surface of the metal is in most cases very superficial. The results obtained are therefore considered unsatisfactory by the manufacturer; not only on account of the small percentage of white lead produced but also because of its possessing less body than the other kinds.From the physical pro- perties of this lead being different from those of common well- prepared white lead it was thought of interest to examine whether its chemical constitution was the same as that of the harder kind; and with this view the following specimens of soft lead were subjected to analysis. W. BLACBETT LEAD. FIRST ANALYSIS. Weight operated on = 17.75 grs. Weight of carbonic acid found = 2-04 grs. = 11.49~. c. , oxide of lead = 15.29 , = 86-19 , water. . -.42 , -2.37 , 7-17.75 100~00 SECOND ANALYSIS. Weight operated on = 20.64gps.Weight of carbonic acid found = 2.42 grs. = 11-67p. c. , , oxide of lead water . . 0 = - 17.77' , *48 J = - 86-09 , 2.32 , -. 20.66 100*08 1. 11 Carbonate of lead . 69-80 70.93 Oxide of 'lead . . 27.83 2683 Water . . 2-37 2.32 .. 100*00 100*08 MR. 3 A. PHILLIPS ON DARLINGTON LEAD. FIRST ANALYSIS Weight operated on = 19.70 grs. Weight of carbonic acid found = 2-24grs = 11.37 p. c. , oxide of lead . = 17.02 , = 86-40 , _. , water . -*44 , -2.23 , 19.70 100.00 SECOND ANALYSIS. Weight operated on = 22.73 grs. Weight of carbonic acid found = 2.66 grs. = 11.70 p c. , oxide of lead + = 19.58 , -= 86.14 ,, -, water . *-050 , -2.20 , c__ c__- 122.74 100*04 or I. 11. Carbonate of lead .. 69-09 71.09 Oxide of lead . 28-68 26.75 Water . * . 2.23 2.20 -I -Ioo*oo 100.04 The foregoing results indicate that each of the four different specimens examined was composed of two equivalents of carbonate of lead united to one equivalent of the hydrated oxide of that metal and the composition of this salt will therefore be represented by the formula 2 PbO. CO + PbO. HO. The numbers given beneath which represent the mean composition of the specimens analysed and the theoretical percentages of a salt so constituted will be forind to agree very closely Mean of results Theoretical obtained. Oxide of lead 86.38 86.31 Carbonic acid 11.31 11.50 Water . 2.31 2.21 100.00 100.02 Several other specimens of white lead were examined during the pro- gress of these investigations ; but in rare instances only did the results obtained indicate a formula differing from that above given.THE CARBONATES OF LEAD. An exceptional composition of this kind was observed in a speci-men of Blackett lead which was analysed by the method already described and yielded the following numerical results FIRST ANALYSIS. Weight operated on = 20.97 gre. Weight of carbonic acid found = 2.61 grs = 12-44!p. c. , oxide of lead . = 17.96 , = 85.69 , , water . -*32 , _. -1.52 ) -_. 7-20.89 99-65 SECOND ANALYSIS. Weight operated on = 19.40 grs. Weight of carbonic acid found = 2.47 grs = 12.73 p. C, ,) oxide of lead . = 16-56 , = 85-36 ) _. , water . -*32 , - 1.64 ,, --L-.--19.35 99.73 or I IT.Carbonate of lead 75.63 77*37 Oxide of lead . 22.51 20.72 Water . 1.52 1+64 9P66 9973 The composition of this specimen appears to correspondvery closely with that of a salt having the formula 3 PbO. CO + Pb0. HO as will be observed on comparing the two columns of figures given beneath of which one represents the mean results obtained by analysis whilst the other shows the theoretical composition of a body having the above formula. Mean of results Theoreticai. obtained. Oxide of lead . 85.66 85.52 Carbonic acid 12.62 12.68 . 1.72 1.58 Water . 100*00 99*78* Another of the specimens of Darlington lead examined afforded results which would indicate the composition expressed by the for-mula 5 PbO CO + PbO.HO * In no instance could any appreciable quantity of acetate be detected in the speci-mens of white lead examined. VOL. IVe-NO. XIV. N f 72 MR. J. A. PHILLIPS ON From the great difference observed in the colour and body of various specimens of precipitated white lead which were prepared by 8 variety of methods during the progress of the practical investigation before referred to it was thought desirable to examine the nature of the salts so produced and also to determine the varying cireum- stapces under which they are severally formed. When an equivalent of pure carbonate of soda is dissolved in hot water and continuously added ;to a hot solution of an equivalent of nitrate of lead it will be observed that on the introduction of the first drop of the soda-solution a violent effervescence takes place.This is repeated on the addition of every fresh portion of the alkaline carbonate until about two-thirds of it have been added when carbonic acid ceases altogether to be evolved; although a white pre- ciiitate is still formed on the introduction of each additional quantity of the soda-salt. If on the contrary the hot solution of nitrate of lead be added to that of carbonate of soda no evolution of gas ensues until about two- thirds of the lead-salt have been introduced at which point efferve- scence begins and is continued in a greater or less degree until the whole of the liquor has been added. Of the three specimens of precipitated carbonate of lead examined and of which the composition is given beneath the first was prepared by adding a small quantity of carbonate of soda in solution in hot water to a boiling solution of nitrate of lead in large excess.The second variety was obtained by adding the hot solution of car-bonate to the dissolved lead-salt until the mixture acquired an alkaline reaction. The third salt was produced by adding a solution of nitrate of lead to one of carbonate of soda until the former was ia slight excess. Both solutions were used hot. The three precipitates thus obtained were subsequently washed and dried at 212' Fahr. until they ceased to lose weight by further exposure at that temperature. On subjecting them to analysis by the method before detailed the following results were obtained PRECIPITATED LEAD No.1. FIRST ANALYSIS Weight operated on = 22.72 grs. Weight of carbonic acid found = 3.28 grs. = 14.43 p. c. , oxide of lead . = 19.20 , = 84.50 , , water . -*25 , -1.10 ) 22.73 100.03 THE CARBONATES OF LEAD SECOND ANALYSIS. Weight operated on = 29.11 grs. Weight of carbonic acid found = 420 grs. 24.59 ) *32 ,) = 1443 p. C. = 84.47 ,, --1.10 , -7 lootoo 11 87.69 11.21 1.10 100*00 yy oxide of lead . , water . . Or Carbonate of lead Oxide of lead . Wtater . = ---c_. 29.11 I. . 8P69 . 11.24 . 1.10 100.03 PRECIPITATED LEAD No. 2. FIRST ANALYSIS. Weight operated on = 32-84!grs. Weight of carbonic acid found = 5.12 grs.oxide of lead . = 27.55 ,, J -) water . . -21 ) 32*88 SECOND ANALYSIS. Weight operated on = 2425 grs. Weight of carbonic acid found = 3.75 grs. ) oxide of lead . = 15.59 p. c. -= 83.89 , -*63 1 1-100*11 = 15.46 p. c. = 84.00 ,, - '54 9 100100 IX. 9395 5.51 -54 100~00 s2 = 20.37 ,) -*13 , 2425 I. 94?0 .i 478 . *63 c.I--.I. 100*11 water . Carbonate of lead aide of lead . Water . . MR 3. A* PHILLIPS ON PRECIPITATED LEAD No. 3. FIRST ANALYSIS. Weight operated on = 25.74grs. Weight of carbonic acid found = 418 grs. = 16-23p. c. ,) oxide of lead . = 21.50 , = 83.52 , , water . . -908 , --031 , -__L 25.76 100*06 SECOND ANALYSIS.Weight operated on == 22*26grs. Weight of carbonic acid found = 3.65 grs. = 16.39 p. c. , oxide of lead . = 18.58 ,) = 83.46 , , water * .-*06 YJ -*2r ,) 22.29 100*12 or I XI. Carbonate of lead . 98.63 99.60 Oxide of lead 8 1.12 -25 Water . . *31 *27 100*06 100.12 On examining the above numerical results it will be observed that in neither case do the analytical numbers found lead to any rational formula although it will be seen that in the two first products the water and oxide of lead are present in very nearly equivalent propor- tions and the precipitate may therefore be regarded as a mechanical mixture of carbonate and hydrate of oxide of lead. In the third analysis there is however an evident excess of water probably arising from the substance not having been allowed to dry for a sufficient time before its introduction into the tube in which its decomposition was effected.It was observed during the examination of the different varieties of white lead that they all retain their hygrometric water with great obstinacy as a continual loss of weight was in most instances found to occur during the first forty-eight hours after placing the substance in the water-bath ; but as this loss is altogether far from considerable it is probable that in the case of the third specimen of precipitated lead the loss which occurred during the interval interveningbetween the two last weighings was so small that it was not perceived and that THE CARBONATES OF LEAD.the substance was consequently analysed in a slightly damp state. The precipitated specimens were also found to be decomposed with much greater difficulty than those made by the ordinary process and on this account great care was required to prevent the melting of the tube in which the decomposition was affected. On examining the ordinary corroded leads in a finely divided state by the aid of a powerful microscope no traces of crystalline structure could be perceived even when the soft effloresced variety was employed ; but when the three precipitate specimens were subjected to a power of 300 diameters distinct hexagonal plates became visible. These varied from T&$h to m+rTth of an inch in diameter and appeared slightly yellow by transmitted light.ANALYSIS OF A SPECIMEN OF NATIVE CARBONATE OF LEAD FROM TEESDALE IN THE COUNTY OF DURHAM. The carbonate selected for the purpose of analysis was in the form of imperfect opaque crystals externally coated with a thin lager of hydrated oxide of iron. After carcfully removing this covering with the edge of a sharp knife and examining the surfaces of the crystal through a strongly magnifying lens to determine if the whole had been scraped off they were pulverised in an agate mortar and after being dried at 212' Fahr. until they ceased to lose weight were analysed by the method employed in the examination of the artificial carbonates. In this case no water was remarked to pass from the decomposition-tube ; and the perfectly anhydrous nature of the com-pound is evident from the following analytical results FIRST ANALYSIS.Weight operated on =33.03 grs. Weight of oxide of lead found = 27.61 grs. - 83.66 p. c. , carbonic acid . = -5.30 , - 16-05 , 7-32.91 99.61 SECOND ANALYSIS. Weight operated on =25.11 grs Weight of oxide of lead found = 20.98 grs. = 83.55 p. C. , carbonic acid = 41-15 , = 16.52 , ___I-25-13 t 00.07 These numbers would of themselves indicate the presence of about 2 per cent of oxide of lead in the mineral examined; but on sub-jecting another portion of the same substance to the usual routine VOL. W.-NO. XIV. M4 MR J A. PHILLIPS ON employed in chemical analysis it nas fouud to contain 1.23 per cent of siliceous matter besides traces of iron and lime; and there can consequently be but little doubt that the crystals examined were composed of anhydrous carbonate of lead slightly contaminated with earthy matter and containing small portions of the carbonates of lime and protoxide of iron.The results obtained during the foregoing experiments on the com- position of white lead made by the Dutch process very nearly cor- respond with those of Mulder who examined specimens which indicated compositions agreeing with the first two of the forrnulz above given. Ch. Link* has also communicated an investigation of five different specimens of German white lead all of which yielded results indicating the composition expressed by the formula 2Pb 0.CO -J-PbO. H0.t Dr. Richardson of Newcastle-on-Tyne who has examined this aubject has however obtaineci very different results from those found by Mulder Link and others and I have therefore endeavoured to discover if possible the cause of this apparent discrepancy. The experiments made by this chemist were executed on specimens of white lead which had been heated for a certain time to the tem- perature of 300’ Fahr. before being analysed. His percentages also indicate the total absence of water in the whole of the ten different specimens which he has examined.$ From the high temperature at which Dr. Richardson’s specimens were dried it was thought probable that the water and even traces of the carbonic acid present might be expelled before the substance was subjected to analysis; and in order to determine this point I made use of the following apparatus.FIG 2 * Ann. Ch. Pharm. XLVI 232. i-Similar results have also been obtained by Hochstettel. t Professor Graham’s Elements of Chemistip p 591. THE CARBONATES OF LEAD. f The tube a is filled with caustic potash coarsely powdered and connected by means of a smaller tube and perforated corks with the long piece of combustion-tube b filled with fused chloride of calcium. l'he copper oil-bath d is furnished with apertures through which are inserted the thermometerf and the tubef for the escape of the vapours generated. The sides of this vessel are also provided with tubulatures so placed as to admit the tube c c which is firmly held in its place by perforated corks.The apparatus connected on the other side of the oil-bath is the same as that employed to collect the water and carbonic acid in the former experiments,$ and j being chloride of calcium tubes and h a Liebig's potash apparatus held in a slightly inclined position by the support i. In order to use this arrangement the bath is filled with oil to above the level of the tube c c and placed on a sand-bath supported by the stand E. The weights of the tubes g h and j are now carefully taken and noted and a weighed quantity of the white lead to be examined is placed in the tube e e. This is done by intro- ducing the substance in a small porcelain trough in which it had been previously heated until it had ceased to lose weight in the water-bath.The various parts of the apparatus are now connected as shown in the figure and suspended on the supports ZZ. When this has been done the tap of the aspirator X is so far opened as to allow the water which it contains to escape in intermittent drops and the sand-bath is heated by a small gas-burner protected from currents of air by a metal screen. By operating in this way on numerous specimens of corroded lead it wag observed that the whole of the water was expelled by subject-ing it during six hours to a temperature of 300' Fahr. and it was further found that the pulverised lead began to lose its water be- tween 225' and 250' of the same scale. During these experiments no loss of carbonic acid had in any instance occurred at the temperature to which the salt was subjected and further investigations were therefore made with a view of deter-mining approximatively the point at which this elimination first takes place.With this view the temperature was in the next experiment raised to 350° and on re-weighing the various parts of the apparatus at the expiration of four hours the substance was found to have lost traces only of carbonic acid. On subjecting however 70.25 grains of carbonate of lead having the formula 2 YbO. CO +PbO. HO to a temperature of 400' Fahr. during ten consecutive hours it was found to have lost 1.62 of water DR. MUSPRATT ON THE COMBINATION and 1.65 of carbonic acid and its percentage composition was COW sequently represented by the following numbers Pound.Theoretical. Oxide of lead . 90.60 9 1-06 Carbonic acid . 9.40 8-94! 1oooou f00.00 On examining this result it will be found that besides the whole of the water exactly one-fourth of the carbonic acid present had been expelled and the salt remaining in the porcelain trough was conse-quently a dicarbonate of lead having the formula PbO. CO + PbO. This residue had not in the least altered in appearance from the time of its introduction into the oil-bath being perfectly white and exactly resembling ordinary white lead. The above results were confirmed by numerous other experiments but I have not yet determined at what temperature the second a%om of carbonic acid is driven off. From the foregoing experiments it is however evident that com-mon white lead loses the whole of its combined water at 300° Fahr.and that at a temperature of about 50' higher its carbonic acid begins also to be eliminated. \

ISSN:1743-6893    

DOI:10.1039/QJ8520400165

出版商:RSC    

年代:1852

数据来源: RSC

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DR. MUSPRATT ON THE COMBINATION XVII.-On the Combination of Arsenious Acid and Albumen with Remarks on Lielrig’s Theory. BY SHERIDAN MUSPRATT,Ph.D. F.R.S.E. My time has been so much occupied the last year that I have had no opportunity of investigating thoroughly the compound of arsenious acid and albumen. I. have latterly however paid con-siderable attention to this subject owing to the following statement appearing in the Transactions of the Chemical Society :* ‘‘If water so readily extracts arsenious acid both from the compounds formed in the laboratory and from those which nature has prepared surely we may conclude that its retention is simply mechanical arid affords no ground for the theory which that eminent chemist Liebig has raised upon it,” * Chem.SCC. Qu. J. 111 16. OF ARSENIOUS ACID AND ALBUMEN. Liebig writes “Arsenious acid enters into a very firm combi-nation with membranes and gelatinous tissues ; the arsenious acid combining with these gives to them the power of resisting decay and putrefaction.” I cannot believe that so renowned a philosopher could have pub- lished such statements unless he was convinced of their correctness from experiments and analysis. I now enter upon my researches. QUALITATIVE ANALYSIS. I took 0.107 grm. of dissolved arsenious acid and 12.67 grms. of the glairy albumen of eggs. They were intimately triturated together for about twenty minutes coagulated by heat and evapo- rated to dryness in a water-bath. The white residue affused with distilled water and filtered yielded a filtrate which gave no deposit of arsenic on copper by Reinsch’s test nor any stains on porcelain by Marsh’s apparatus.When the residue on the filter was heated with pure sulphuric acid and then submitted to the preceding experi- ments arsenical indications were immediately obtained proving that a combination of arsenious acid and albumen had occurred. QUANTITATIVE ANALYSIS. 61.07 grms. of albumen were mixed as above with 0.603 grm of dissolved arsenious acid I washed the mixture after evaporation to dryness with distilled water until not a trace of arsenious acid dissolved out. The filtrate was introduced into a bottle provided with a glass stopper some hydrochloric acid added and a stream of sulphide of hydrogen passed through the menstruum.The flask was then closed and allowed to rest for some hours; after this pure carbonic acid was transmitted through its contents with the view of expelling all the free sulphide of hydrogen the sulphide of arsenic was then collected on a tarred filter dried at 100”C. and weighed. Weight of tersulphide of arsenic . 0.270 Equal to of arsenious acid . . 0.217 b The above results therefore prove incontestably that the albumen had combined with 0.386 grm. of arsenious acid. This compound is not poisonous. I heard from Professor Gregory that he per- formed some experiments in Dublin in 1837 which satisfied him that Liebig was right; and Sir Robert Kane has stated that the ‘‘com- MR. A. BEALEY ON AN ORE OF CINNABAR pound of al%urnen with the acidrr is generally somewhat soluble; with metallic oxides insoluble.”* When the white of egg is used as the antidote to metallic poi.irons it acts no doubt mechmically as well as chemically-a large portion being enveloped and protecting the mucus membrane of the stomach while a small portion enters into combination.The analytical results cited are to my mind so convincing that to descant further upon the matter would be superfluous; and I may close this notice with the following able remarks of a medical man with which I entirely coincide. “There is in my opinion no doubt that the metallic poisons are capable of uniting with animal matters; and this I apprehend is perfectly well known to all toxocologists and is the universally received explanation of their antiseptic properties.’.’

ISSN:1743-6893    

DOI:10.1039/QJ8520400178

出版商:RSC    

年代:1852

数据来源: RSC

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180 MR. A. BEALEY ON AN ORE OF CINNABAR XVIII.-Bxarnination of an Ore of Cinnabar from New Almaden CuEi,jbrnia. BY ADAMBEALEY, EsQ. M.A. This ore has long been known to mineralogists as abundant ad very accessible but it had not attracted much notice until the recent development of the mineral wealth of California led to more extended inquiry into the actual extent of its distribution and rendered im- proved methods of reducing it of great interest and value. The mine or principal deposit of this mineral is thus described by Lyman in 1848:t “New Almaden lies between San Francisco and Monterey near the coast. It is 1200 feet above the plain and is situated upon a ridge of the Sierra Ad which consists of a greenish talc-rock. “The cinnabar is found in nests in a stratum of a yellowish earth which is 42 feet in thickness.The occurrence of this mineral has been known to the natives from time immemorial as the cave of red earth which they employed for painting their bodies. “During Lyman’s stay the daily produce from 1,600 Ihs. of cinnabar distilled in a rudely constructed apparatus was from 200 * Chemistry of Agriculture and Physiology page 377. 4-Liebig and Kopp’s Annual Report by Hofmann and De La Rue. Val. If p. 388. PROM NEW ALMADEN CALIFORNIA. It31 to 300 lbs. of mercury and in the last three weeks of his residence the total amount of mercury obtained was about 10,000 lbs. “‘Cinnabar had likewise been found in fifteen or twenty other pjaces within a circumference of a few miles.” A more recent account of this mine was politely communicated) by Dr.Forbes and accompanied a specimen of the ore sent to Pro-fessor Hofmann for analysis at whose suggestion the following Fxamination was undertaken. “The mine of New Almaden is situated in Upper California near Santa Clara on the coast not far from San Francisco. It is the property of a company of English and foreign merchants and is leased to a company of the same kind. “It has been in active operation for about six or eight months. The vein is very large and ‘crops out’ on the surface where it is worked. The metal is extracted from the ore in two ways ‘(First by a series of large iron cylinder-retorts heated in furnaces and discharging their produce into water where the metal is con- densed.Secondly by brick furnaces in which the €uel (wood) is inter-mixed with the ore. By theseoperations the ore gives from 30 to 45 per cent of its weight of mercury. “The mine produced in the month of November 1850 not less than 127,500 lbs. of mercury.” The ore as exhibited in the specimens sent some of which weighed as much as 14 avoirdupoise lbg. has a bright red colour slightly inclining to purple and appears to have been imperfectly cleared from a soft light-brown earth which can easily be scraped from its surface. It breaks without much difficulty under the hammer ad is afterwards easily reduced to powder with the exception of some bright crystalline particles which are extremely hard. The surfaces of recently broken ore appear much more purple than those long exposed.It is traversed at irregular intervals by very thin bands of white hard crystalline material apparently calcareous and siliceous. When in the state of fine powder it has a very bril- liant vermillion colour many shades darker than the massive ore. Its sp. gr. is 4.410. In a preliminary examination it exhibited the ordinary phenomena of a mercurial sulphide associated with siliceous matter. A portion of the ore was digested with nitro-hydrochloric acid and the insoluble residue separated by filtration. The solution examined by the usual methods contained mercury sulphur iron alumina a trace of nickel lime and magnesia. 182 MR. A. BEALEY ON AN ORE OF CINNABAR The part insoluble in acid consisted of silicic acid and very minute traces of lime and potassa.In estimating the principal constituents of this ore the mercury was determined as sulphide of mercury and as metallic mercury by distillation with lime. 1. 2.238 grms. gave 1*801grm. of sulpbide of mercury. 2. 1.057 , , 0*860 9 >Y 3. 250 grms. distilled with 500 grms. of lime gave 175.540ps. of metallic mercury. The sulphur was estimated as sulphuric acid. 1. 1.349 grm. gave 1.120 grm. of sulphate of baryta. 2. 1.248 , , 1.025 ,> Yf Iron as sesquioxide. 1. 1.940 grm. gave 0.024grm. of sesquioxide of iron. 2. 1.610 , , 0*022 , Y> Lime as carbonate of lime. 1.940 grm. gave 0.0485 grm. of carbonate of lime. Alumina. 1.940 grm. gave 09012 grm.of sesquioxide of aluminum. Magnesia as pyrophosphate of magnesia. 1.940 grm. gave 0*0525grm. of pyrophosphate of magnesia. Insoluble residue. 1. 1-349grm. of ore gave 0.193grm. of silicic acid. 2. 2.238 ,) , 0.325 grm. of silicic acid and traces of lime and potassa too slight to be estimated. The percentages corresponding to these numbers will be found in the table appended at the end of this note. CINNABAR FROM ALMADEN SPAIN. As the appearance of an ore of cinnabar so rich in mercury and found in such profuse abundance seems likely to have a material influence upon the permanent supply ordinarily found in commerce a comparison was instituted between this and the ore derived from Almaden in Spain well known as the chief source of Spanish mercury.The specimen of ore examined was obtained from Mr. Tennant FROM NEW ALMADEN CALIFORNIA. and described as one from which a considerable part of Spanish mercury was derived. It is like the Californian ore massive but much less brilliant and much harder. Throughout its mass small patches of yellow iron pyrites are irregularly distributed. When in the state of fine powder it has a dull brick-red colour in striking contrast with the brilliant vermillion cinnabar from California. Its sp. gr. is 3.6212. Submitted to the same examination and treated similarly to the last it exhibited the same phenomena with variations too slight to require especial notice. The part soluble in acid consisted chiefly of mercury sulphur iron with traces of alumina and lime; the part insoluble in acid of silicic acid and alumina.The principal constituents of the mineral were determined as be- fore Mercury as sulphide of mercury ; iron as sesquioxide of iron ; sulphur as sulphuric acid; silicic acid as such. Mercury. 1. 1.009 grm. of ore gave 0.443grm. of sulphide of mercury 2 1.0205 , , 0.447 , ,I Sulphur as sulphuric acid. 1*0205grm. of ore gave 1.208gri. of sulphate of baryta. Tron. 1*009grm. gave 0.148grm. of sesquioxide of iron. Insoluble residue. 1. 1°0205grm. gave 0.35'7grm. of silicic acid and alumina. 2. 1.009 , , 0.353 13 3s I have moreover examined specimens of cinnabar ore from Mo-schellandsberg and from Wolfstein. CINNABAB FROM MOSCHELLANDSBERG.This specimen and the following one were obtained from Mr Griffin and described as being worked though of comparatively rare occurrence. The mineral is a dark red-brown crystalline material heavy very hard and with difficulty reduced to powder. Its sp. gr is 4735 Examined and treated as the minerals previously mentioned it was found to consist principally of mercury sulphur iron alumina MI?.A. BEALEY ON AN O8E OF CINNABAR land silicic acid. Mercury and sulphur only were determined quanti-tatively. Mercury. It. 1.166 grm. of ore gave 0.9012 grm. of sulphide of mercury. 2. 1.255 , 3 0.967 Y> >f Sulphur as sulphuric acid. 1.3075 grm. gave 1.050 grm. of sulphate of baryta. Insoluble residue. 1.3075 grm.gave 0.2235 grm. CINNABAR FROM WOLFSTEIN. This ore is a grey earthy-looking mineral with dark livid patches occurring at intervals in its substance. It is very hard and becomes a light puce-coloured powder. It was found to consist of mercury sulphur alumina and a trace of iron and silicic acid 1.516 p.yielded 0416 grm. of sulphide of mercury. From the above results the following per centages were calculated COMPOSITIONS OF VARIOUS CINNABAR ORES. 2 CALIFORNIAN. ALMADEN SPAIN. MOSCHELLANDSBERG. WOLPSTEIN. z f4 1. 2. 3. Mean. 1. 2 Mean. 1. 2. Mean. 5 Mercury . 69-36 ‘70.13 7‘0.23 69-90 37.84 37.75 37.79 66.60 67-13 66.86 18-00 g Sulphur . 11.38 11.21 -11.29 16.22 -16.22 11.01 -11.43 c? Insol. * L 3 Iron .. 1.23 -1.23 10.36 -10.36 Qesidue17.09 -17.09 73-31 -J? _I Lime . . 2-40 -1040 Alumina . 0.61 -0.61 Magnesia . 0.49 -0.49 C d Silicic acid and Fi 8ilicic acid 14.30 14.52 -14.41 alumina . . 35.12 99.33 9949 MR. M. W. JOHNSON ON From these numbers it is evident that provided the specimens represent the average minerals worked the ore of California contains nearly double the amount of mercury found in the Almaden ore and nearly fourfold that of the specimen of Wolfstein while it approaches the composition of pure cinnabar even more nearly than the mineral of Moschellandsberg

ISSN:1743-6893    

DOI:10.1039/QJ8520400180

出版商:RSC    

年代:1852

数据来源: RSC