摘要:

MARCH, 1906 Vol. XXXI., No. 360. THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE annual meeting of the Society was held on Wednesday evening, February 7, In the Chemical Society’s Rooms, Burlington House. The President, M i . E. J. Bevan, occupied the chair. The minutes of the previous meeting were read and confirmed. Dr. L. T. Thorne and Mr. J. H. B. Jenkins were appointed scrutators of the ballot-papers for election of Officers and Council. The HON. TREASURER (Mr. E. W. Voelcker, A.R.S.M.) presented his annual report, with the accounts of the Society for 1905. On the motion of Mr. ARTHUR R. LING, seconded by Mr. JOHN WHITE, the report was unanimously adopted, and a vote of thanks accorded to the Hon. Treasurer for his services during the past year. The HON.TREASURER, having responded, proposed a vote of thanks, which was unanimously passed, to the auditors, Mr. W. P. Skertchly and Mr. Arthur R. Ling. A vote of thanks to the Ron. Secretaries, Mr. Alfred C. Chapman and Mr. P. A. Ellis Richards, was proposed by Dr. DYER, seconded by Dr. SCHIDROWITZ, and unanimously passed. Mr. CHAPMAN acknowledged the vote of thanks. A vote of thanks to the President and Council of the Chemical Society for their kindness in allowing the Society the use of their rooms at Burlington House during the past year was moved by the PRESIDENT, and unanimously agreed to. The PRESIDENT delivered his annual Address. Mr. HEHNER proposed that a very hearty vote of thanks be accorded to the President for his Address, and that his permission be asked to publish the Address in the ANALYST.Mr. KITTO seconded the resolution, which was carried unanimously. The PRESIDENT briefly responded. The scrutators having reported to the President the result of their examination The PRESIDENT announced that the Officers and Council for 1906 had been President.-E. J. Bevan. Past-Pmsidents (limited by the Society’s Constitution to ten in ~u!mber).-M. A. Adams, F.R.C.S. ; A. Duprh, Ph.D., F.R.S. ; Bernard Dyer, D.Sc. ; Thornas Fairley ; of the ballot-papers, elected as follows :66 THE ANALYST. W. W. Fisher, M.A.; Otto Hehner ; Alfred Hill, M.D. ; J. Muter, Ph.D.; Sir Thomas Stevenson, M.D., F.R.C.P. ; J. Augustus Voelcker, M.A., B.Sc., Ph.D. Vice-Presidents.-L. Archbutt, W. J. Dibdin, B. Kitto. Hon. Treasurer.-E.W. Voelcker, A.R.S.M. Hon. Secretaries.-Alfred C. Chapman, P. A. Ellis Richards. Other Nembers of Council.-Arthur Angel1 ; Julian L. Baker ; R. Bodmer ; M. Wynter Blyth, B.A., B.Sc.; Charles Estcourt; D. Lloyd Howard; J. H. B. Jenkins ; E. W. T. Jones ; S. Rideal, D.Sc. ; Alfred Smetham ; W. Lincolne Sutton ; John White. The monthly ordinary meeting of the Society was held on Wednesday evening, February 7 , in the Chemical Society’s Rooms, Burlington House, immediately after the annual meeting. Certificates of proposal for election to membership in favour of Messrs. S, Dickson, J. Evans, F. Hughes, G. Patterson, and H. Thompson, were read for the second time; and certificates were read for the first time in favour of Messrs, George Craig, P.I.C., 95, Bath Street, Glasgow, analytical and consulting chemist ; John B.Gall, F.I.C., A.C.G.I., Knoxland, Erith Road, Belvedere, works chemist to Messrs. Callender’s Cable and Construction Company, Limited ; H. Norman Hanson, Field Head, Brighouse, assistant to Mr. F. W. Richardson; Bernard W. Methley, 21, Clifton Mount, Rotherham, chemist to Messrs. Steel, Perch and Tozer, Sheffield; Frank Darby Ratcliff, 203, Ashted Row, Birmingham, chemist to Messrs. Holbrooks, Limited ; and Frederick Robertson, 128, Wellington Street, Glasgow, analytical and consulting chemist. Dr. H. W. Wiley was elected an honorary member ; and Messrs. Geo. Clarke, Junr., C. A. Hill, B.Sc., and H. J. Horton, were elected members of the Society. The following papers were read : “ Note on Dutch Cheese,” by Cecil H. Cribb, B.Sc. ; ‘‘ The Assay of Mercury Ores,” by G. T. Holloway, A.R.C.Sc. ; ‘“The Purification of Zinc and Hydrochloric Acid,” by L. T. Thorne, Ph.D., and E. H. JeBers; and “The Facing of Rice,” by Cecil H. Cribb, B.Sc., and P. A. Ellis Richards. The President, Mr. E. J. Bevan, occupied the chair.

ISSN:0003-2654    

DOI:10.1039/AN9063100065

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

66 THE ANALYST. THE ASSAY OF MERCURY ORES. BY. GEORGE T. HOLLOWAY. (Read at the Meeting, FebmLary 7, 1906.) ALL the mercury of commerce is obtained by the roasting of cinnabar (HgS) in a, current of air. The sulphur burns to the dioxide, and the liberated mercury, together with such native mercury as is frequently associated with the cinnabar, distils over and is collected in condensers and flues. Despite the enormous difficulty which is experienced in condensing the mercury and minimizing loss by leakage and flouring, the cheapness of the process and its comparative simplicity render it possible to treat,THE ANALYST. 67 ores of extremely low value, and the bulk of the mercury now produced has been obtained from ores containing an average of between 8 per cent. and 1 per cent.of the metal. It is true that ore as rich as 7 to 8 per cent. is worked at Almaden, in Spain, the oldest and richest mine in the world; but at Idria (Austro-Hungary), Nikitowka (South Russia), and Napa Consolidated Mines (California) respectively standing second, third, and fourth in order of production, the ore averages well under 1 per cent., as it does also in all other mines whose outputs are sufficiently large to count as factors in the world’s production, which is stated to have amounted in 1904 to 3,581 tons of 2,240 pounds. Cinnabar and native mercury usually occur impregnating or disseminated throughout limestones, dolomites, sandstones, etc. Copper and other ores frequently contain mercury, but not in quantity sufficient for extraction on the large scale.Bituminous matter commonly occurs in association with it, and in a few districts, as in Kweichow (China), antimony sulphide is met with, and seriously interferes with the extraction on account of the flouring of the mercury. The cinnabar and native metal, although frequently found in masses and occasionally in crystals, is practically all so mixed with the gangue and is so friable, and, notwithstanding its great density, so easily lost when “dressed,” that no dressing plant has been found capable of treating it profitably, and although hand-picking is occasionally practised, almost the whole of the ore is roasted exactly as it leaves the mine. The old method of assay consisted in heating a mixture of the ore with iron filings or litharge or lime to redness in a glass tube closed at one end and bent down at the other, whichlatter dipped into water.A length of magnesite or sodium bicarbonate at the closed end of the tube permitted the generation of a stream of carbonic acid gas to drive the remaining mercury vapour out of the tube after the ore had been decomposed. The mercury was collected, dried, and weighed as metal. This method is excallent for picked or rich material assaying, say, 20 per cent. or more, and, as stated later, is still probably the most accurate for such material, on account of the large amount of ore which can be taken for assay, but is absolutely useless for the ordinary ore, which probably accounts for 99 per cent. of the world’s output. The well-known Eschka process (Zeit. fiir Anal.Chm., vol. ii., p. 334), in which a small quantity of the ore was heated with iron filings in a small crucible, and the evaporated mercury was collected on a weighed disc of gold, was therefore introduced. The gold disc was cup-shaped, and was formed with a flange fitting on the crucible top. I t contained cold water, which was occasionally renewed during the progress of the test, The mercury became condensed on the gold, which, after being weighed, only required to be heated gently to drive off the mercury ready for the next test. As regards accuracy, Eschka’s process leaves little to be desired, and the use of a strip of gold foil placed at the open end of a small ignition tube of about +inch bore, in which a mixture of iron filings and a mineral or salt containing mercury is heated, forms a most delicate test for mercury.The presence of mercury to the extent of only i+G of 1 per cent. may thus be proved, and accurate estimations may be made when the total mercury only amounts to &th per cent. Wet processes are inapplicable to such ore.68 THE ANALYST. In 1898, R. E. Chism (Engifieering and Mining Journal, October 22, 1898, p. 486) introduced a modification in which the gold cup was replaced by a piece of silver foil pressed into shape into the top of the crucible, and his results appear to have been perfectly satisfactory. The modification about to be described differs from that of Eschka, or Chism only in the construction and arrangement of the apparatus, and is shown in the Itccom- panying drawing. Some difficulty is experienced in fitting the gold cup or silver foil “mercury- tight ’’ to the crucible top, and the cooling water requires frequent renewal, as the collecting power of gold or silver is much reduced when warm.The author therefore employs a flat sheet of “fine” silver, which may be purchased of any thickness at about 3s. 6d. per ounce troy, and which, after annealing by warming to dull redness for a few seconds in a flame, may be rubbed perfectly flat between two surfaces of glass or wood. The silver may conveniently be somewhat thinner than a visiting- card, and is cut into a circular disc, F, about 2 inches in diameter, weighing from 2 to 6 grams according to its thickness. If of the former weight, it can be con- veniently weighed on an assay balance, but it must be held up to the light and examined to insure absence of pin-holes, which often occur in thin foil, and which spoil the assay through escape of mercury.The crucible A may conveniently be of the deep form shown, and abopt 14 inches aide by 12 inches deep, and is ground down perfectly flat at the mouth on emery-paper. An ordinary Berlin porcelain crucible is used. A square plate, E, of silver foil about + inch wider than the plate F is used as a, cover. The plates E and F are kept cool by a round copper vessel, B, about 2 inches in diameter, with pipes, C , soldered in as shown for entrance and exit of the cooling water. The vessel B consists of a spun cap of copper soldered upon a flat copper disc with a turned up rim, D, which collects such water as occasionally condenses on the cooler.The copper may be about & inch thick. The top of a round tin box would serve equally well for the body, but it is advisable to have the bottom of copper on account of its high conductivity. A piece of tin, G, cut out to receive the crucible, localizes the heat around the crucible bottom and rests on an ordinary tripod stand. The ore to be assayed is heated with iron filings free from grease. The filings are best prepared by heating a quantity of several pounds in a covered crucible to a fair red heat for about an hour. All grease, etc., having thus been driven off orTHE ANALYST. 69 carbonized, the cooled crucible is opened; the top layer of the filings, if at all oxidized, is removed, and the filings are sifted.Those which pass through a 60-mesh sieve and those which pass a 30-mesh sieve are kept in separate stoppered bottles. The ore is prepared by grinding it very finely, and may be dried before assay if containing no free mercury; but if, as commonly happens, any native mercury is present in a finely-divided state, practically the whole of it may be lost in drying. In that case it must be assayed as received and calculated out on the dry weight. The loss of mercury in drying may be ignored in the determination of moisture in any ordinary ore, as it would scarcely affect the result even in the second decimal place. The amount of ore to be taken for assay depends on its richness, as the silver foil has only a limited power of retaining mercury. It is advisable to weight out : 2 grams if the ore contains under 1 per cent.of mercury; 1 gram if the ore contains between 1 and 2 per cent. of mercury; 0.5 gram if the ore contains between 2 and 5 per cent. of mercury; 0.25 gram if the ore contains between 5 and 10 per cent. of mercury. If the ore contains over 10 per cent., correspondingly less should be taken. The ore is carefully mixed in the crucible with about 10 grams (roughly weighed) of the 60-mesh iron filings, and the mixture is covered with about 5 grams of the 30-mesh filings, even when only so small an amount as 0.25 gram of ore is used. The crucible is placed in the holder G on a tripod stand, the cleaned, flattened, weighed silver disc F is placed on the crucible with the disc E above to keep it clean, the cooler B is placed over all, and a weight is placed on the cooler to prevent displacement. Water supplied through a rubber tube traverses the cooler.A small Bunsen or spirit flame is brought beneath the crucible, the flame being of such a size as to just make the crucible bottom red, but so that the crucible is not red more than inch up the side. The heat is continued for twenty minutes, draughts being carefully excluded, as a draught may easily deflect so small a flame and practically stop the distillation. The iron removes the sulphur and also conducts the heat so that the mercury distils off and is collected by the disc F. After twenty minutes, the flame is removed, and after fifteen minutes’ cooling the disc F is removed, dried by placing it in a water-oven for a few minutes, or by holding in tweezers and waving above a flame for a few seconds, cooled, and weighed.The assayer must decide for himself which method to use, and how long to allow for the drying. He should experiment on the disc from one of his assays by damping it, drying, and reweighing until he ascertains the conditions which insure drying without loss of mercury. When the ore contains bituminous matter, as sometimes happens, and as is shown by the smell or by a black or brownish stain on the foil, it is necessary to wash the foil with alcohol and dry as above before weighing. Until the operator is experienced, it is advisable to reheat the crucible with another weighed piece of foil to insure that all the mercury has been driven off, but this is not usually found to be necessary.If the assay has been satisfactory, the mercury will all be seen as a dull or bright perfectly circular film on the foil, exactly the size of the crucible rim. If it extends beyond, which may occur either from too much70 THE ANALYST. ore having been taken, so that the silver cannot properly retain the resultant mercury, or from careless flattening or adjustment of the foil, the assay must be repeated. When first using the apparatus, the operator should experiment by repeatedly assaying the same sample, varying the temperature and time until he finds the conditions which yield the highest result. Half a dozen such tests, occupying in all not over three or four hours, will suffice for gaining perfect control over the method. By coupling together a number of coolers with rubber tubes and arranging a row of the assays on a bench, one may easily carry on a dozen assays s t a time in a confined space.An inverted &-gallon Winchester, fitted up like an inverted wash- bottle, and having a regulating clip on its indiarubber discharge tube, will suffice for cooling a battery of a dozen assays. The water leaving the last cooler should not feel more than lukewarm. When the assayer is experienced, he can allow the distillation of one set to continue without watching, while weighing the discs from the previous set. The special precautions to be observed are : (1) Avoidance of excessive heating of the crucible. The edge of the covering foil E should never feel warm to the fingers. (3) Careful adjustment of the foil and coolers and of the weights on the coolers to insure contact all round the crucible top.(4) Careful drying of the foil. (5) Avoidance of draughts. (6) Allowance of the full time mentioned (fifteen minutes) for cooling before removing the foil, lest uncondensed mercury vapour be lost. Although gold has a greater affinity for mercury than silver possesses, and is therefore theoretically better, silver has a greater collecting power weight for weight, and a greater conductivity, and has been proved by comparative tests to give at least equally correct results. No comparative figures are given, because the results are identical within the limits of experimental error. Indeed, if anything, the new method gives slightly higher results. The silver can be used an indefinite number of times, and appears, on account of its greater porosity after prolonged use, to improve.When elaborate care is used, the method, as tested by diluting down a weighed small quantity of pure cinnabar or pure mercury sulphide or oxide, has been found extremely accurate, but under ordinary conditions a slight loss from leakage may be expected, and the difficulty of sampling such an ore as cinnabar renders the danger of error greater. The cinnabar is extremely heavy and the gangue is usually decidedly light, and the fact that cinnabar commonly occurs as little rich patches in the gangue even in the case of very low-grade ore, and is therefore practically freed during crushing, renders it extremely liable to settle, despite the most careful mixing, and to further accentuate the danger of inaccuracy through sampling.This danger is not great when the ore contains under 10 per cent. of mercury, and may be over- come with care ; but when the ore contains 20 per cent. or upwards, it is advisable to distil, say, 10 or 20 grams of the ore in a glass tube with iron filings by the old method already mentioned. The error due to sampling is, of course, then only one-twentieth or one-fortieth of the probable error on a 0.5 gram sample, and the loss from leakage is practically nil. Such ores, however, seldom require to be assayed, and, as already stated, the (2) Cleanliness and perfect flattening of the silver foil F.THE ANALYST. 71 old method is practically impossible on average ores. With such low-grade ores it yields the mercury in beads so small that they can scarcely be collected and dried without heavy loss, and it is extremely cumbrous and slow.On rich ores, the results by the author’s method are sometimes too high and sometimes too low, either result being attributable to difficulty in sampling. As, however, the results are usually slightly low on ores containing over 20 per cent. of mercury when done without excessive precautions, the loss is probably due to leakage. In the case of average ores, the total loss is so small as to be negligible, and duplicate results on a 1 per cent. ore should agree to within 0.05 per cent., a result which cannot be equalled by any wet method. Experiments have been made in which the iron filings are replaced by reduced iron, or by copper, or by litharge, lime, etc. ; but, apart from the extreme convenience of iron filings, the other materials have shown no advantage whatever, and litharge and lime are distinctly less effective. The author is informed that the method works well with salts of mercury, and there is no apparent reason why it should not do so, although the iron filings would in some cases have to be replaced by one of the agents mentioned above, or by some other decomposing agent.He has, however, had practically no experience on this point. The process has been employed in his laboratory for five or six years, and the apparatus has been sent to mercury mines in Russia, China, Italy, and British Columbia, where it has been in constant use. At two mines, the gold cup process which was then in use has been abandoned in its favour on account of its greater convenience and speed, and at all these mines it has been constantly employed for valuing, selling, or buying the crude ore, for assaying tailings, and for controlling the working of the furnaces, etc. The above description may therefore be taken as that of a proved rather than a suggested method of assay.DISCUSSION. The PRESIDENT (Mr. Bevan) asked if ths process could be used on a larger scale than Mr. Holloway had indicated, using a larger quantity of the ore. Mr. HOLLOWAY said that the use of a larger quantity of ore did not increase the accuracy of the method if one had a good balance ; in fact, the process worked better with the small quantities recommended in the paper. Mr. KITTO said that for many years he had used a gold cup having a fairly large cavity, and had found no difficulty in getting very accurate results without the addition of the ingenious apparatus which Mr. Holloway had described. He had been much interested in the device for automatically cooling the silver foil. Probably where, as in a mine, a large number of determinations had to be made, it would be very useful, but under ordinary circumstances he really did not think it necessary to complicate the very simple original apparatus. He had had no difficulty in getting the flange of the gold cup firmly fixed and accurately adjusted to the edge of the crucible. * + I + * % + B

ISSN:0003-2654    

DOI:10.1039/AN9063100066

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

72 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. The Detection, Determination, and Rate of Disappearance of Form- aldehyde in Milk. R. H. Williams and H. C. Sherman. (Journ. Amer. Chem. SOC., 1905, xxvii., 1497.)-The authors find that by means of the potassium cyanide method (ANALYST, 1904, xxix., 5) formaldehyde in milk can be approximately determined at any concentration greater than 1 part in 160,000. They find that aqueous solutions of formaldehyde containing from 1 : 5000 to 1 : 40,000 lose steadily in strength on standing, the loss being not merely due to polymerization, but to actual destruction of the formaldehyde. Within the same limits, formaldehyde added to milk disappears about ten or twenty times as rapidly as from aqueous solutions of the same strength.Stronger solutions are much more stable; thus, an aqueous solution of 1 : 1,000 showed no appreciable loss after five months. From milk containing 1 part in 1,000 the rate of disappearance was the same as for an aqueous solution of 1 : 5,000. Souring of the milk does not affect the rate of dis- appearance. The hydrochloric acid and ferric chloride test is sensitive to a dilution of 1 : 250,000. The test may be made more satisfactory by adding 50 to 75 CA. of cold water to the milk after keeping it just below the boiling-point for one minute as usual; the colour obtained in this case, however, is very fugitive. The gallic acid test is much more delicate than the ferric chloride test. Sourness of the milk does not affect the reaction. A.G. L. Composition of the Fat of Pigs fed on Foods Rich in Oil. K. Farn- steiner, K. Lendrich, and P. Buttenberg. (Zeit. Untersuch. Nab. Gemssm. , 1906, xi., l-S.)-The particular object of the present experiments was to ascertain whether the oily constituents of the fodder were deposited in the body fat of pigs fed on such fodder. The results show that the fat of pigs fed on cottonseed-meal gives a decided reaction with Halphen's reagent, but that the fat in no case contains phytos- terol, and is consequently thus distinguished from lard adulterated with cottonseed- oil. (Cf. ANALYST, 1904, p. 315.) w. P. s. On the Occurrence of Arsenio in Wines. H. D. Gibbs and C. C. James. (Journ. Amer. Chem. SOC., 1905, xxvii., 1484.)-The authors have exa.mined a total of 352 wines, some bottled and some in cask, and have found arsenic in 52 cases, in quantities ranging up to 1 part of arsenic in 2,500,000 of wine.Generally, however, the quantities found were much smaller than this. As probable sources of the arsenic they indicate the arsenical sprays used upon the vines, the sulphur burned for sulphuring the wine and receptCtcles, and, perhaps, also the lead-shot used in cleaning the bottles. The method used in testing for arsenic consisted in making the wine alkaline with milk of lime, evaporating to dryness, and igniting the residue a t a, low red heat. The ash was treated with sulphuric acid (1 to 3), the solution filteredTHE ANALYST. 73 and introduced into the generator of a Marsh apparatus. As generator a 250 C.C.Florence flask was used, Kahlbaum's zinc and pure sulphuric acid being used to generate the hydrogen. The action was started by adding a few drops of platinic chloride.':: Immediately after adding the sulphuric acid the air in the apparatus was swept out by a rapid current of carbon dioxide, and the solution to be tested was then added. The evolved gas was passed through a spiral of lead acetate paper and then through calcium chloride, after which it entered a Jena glass tube of 0-7 om. internal and 1.0 cu. external diameter drawn down to a constriction from 10 to 15 em. long and 2 mrn. external diameter. The tube was heated for a space of 10 to 15 cm., pro- tected by wire gauze, before the constriction, the heating being continued for one hour. The electrolytic generator of Thorpe was also tried, but discarded because in some eases it failed to reveal the presence of any arsenic in wines known to contain arsenic.A. G. L. Process for Determining the Quality (Fineness) of Flour. N. Wender. (Zeit. U?ztersz~ch. Nahr. Gem~ssm., 1905, x., 747-756.)-Wheat and other grains contain an enzyme capable of liberating oxygen from hydrogen peroxide, and upon the fact that this enzyme resides principally in the embryo and outer portions of the grain, the author bases a process for distinguishing between best white flour and other flours containing more of less bran or inferior flour. I t is recognised that;, taken by itself, the colaur of flour is no criterion in judging whether a sample is best quality, " seconds," '' thirds," etc.The process is carried out as follows : 25 grams of the flour are rubbed down with 100 C.C. of water until free from lumps and then rinsed into a flask with a further 100 C.C. of water. The flask is closed by an indiarubber stopper carrying a tapped funnel and a delivery-tube connected to a measuring-tube filled with water. Ten C.C. of hydrogen peroxide are then introduced through the funnel, and the action allowed to proceed for about thirty minutes at a temperature of 20" C. Tho volume of the liberated gas is then read off. The following examples are given, in which the results are calculated for 100 grams of meal : Wheat starch, 8 C.C. ; wheat flour, 169 C.C. ; wheat bran, 342 C.C. ; rye flour, 153 C.C. ; rye bran, 330 C.C. ; maize flour, 389 C.C. In a series of flours of decreasing quality, the finest flour gave 128 c.c., and the coarsest 486 C.C.The author admits that many more analyses must be made before any degrees of quality can be fixed by this method, but considers that the latter will be of use when the flours of different countries, mills, etc., have been examined and classified. w. P. s. A New Adulterant of Lemon-Juice. H. Matthes and F. Muller. (Zeit. Untersuch. Nahr; Genzhssm., 1906, xi., 20, 21.)-A sample of so-called lemon-juice gave the following results : Alcohol, by weight, 5.43 per cent.; total solids, 13.47 per cent.; total acidity, as citric acid, 8.19 per cent.; mineral matter, 0.205 per cent.; alkalinity .of ash, 0.49 C.C. acid ; phosphoric anhydride, 0.05 per cent. ; polarization after distillation, + 4.5" in 100 mm.tube. The sample contained starch-syrup, evidently * It has been shown that the use, in this way, of platinic chloride is inimical to the cosrect estima- tion of arsenic. cf. Chapman, this vol., p. Q.-EDITOR.74 THE ANALYST. Alcohol ... ... ... ... I 14.55 Total solids ... ... ... ... 10.11 Mineral matter ... .., 1.. 0.065 Total acidity, as tartaric ... 8.029 Sugar ... ... ... ... ... none added to imitate the pectinous substances of pure lemon-juice and the amount of phosphoric anhydride found was probably due to the addition of a salt of this aoid. w. I?. s. 19.40 19.91 27.84 11.60 18.54 9.74 11.56 15.57 9.38 0.174 0.082 0*119 none none none Composition of Lemonade Essences. Utz. (Zeit. ofentl. Chem., 1906, xii., l2-13.)-The liquids to which the following analyses refer are sold for the purpose of making lemonade and similar drinks by diluting the liquid with water, soda-water, etc.They consist essentially of an aqueous solution of tartaric or citric acid, to which an alcoholic solution of certain flavouring substances (esters) are added. The figures exprese grams per 100 C.C. : Raspberry 1 Raspberry 1 Lemon 1 Lemon Essence A. Essence B. Essence A. Essence B. All four samples were strongly coloured with coal-tar dyes, and two of them- Raspberry Essence B and Lemon Essence B-contained not inconsiderable quantities of saponin. w. P. s. On the Colourihg Matter of Saffron. F. Deeker. (Chem. h i t . , 1906, xxx., 18.)-Crocetin, the colouring matter of saffron, has hitherto only been isolated in an amorphous form, since the readiness with which it resinified prevented its being obtained in 8 crystalline condition.The author, however, has succeeded in obtaining crocetin crystals of constant composition by digesting the resin-free solution of the colouring matter in very dilute sodium hydroxide solution at 60" to 70" C., with an excess of ammonium carbonate solution. The ammonium compound of crocetin was deposited from the liquid on cooling, in the form of yellow needles, which dissolved readily in alkalies, but were only sparingly in water and alcohol. The addition of ammonium carbonate to any of these solutions reprecipitated quantitatively the crocetin compound. An elementary analysis gave the following results : Carbon, 64.60 ; hydrogen, 8-70 ; nitrogen, 8.06 ; and oxygen, 18.64 per cent.C. A. M. Separation of the Conium Alkaloids. J. von Brawn. (Berichte, 1905, xxxviii., 3108-3113 ; through Pharm. Jour., 1905, vol. 75,909.)-The separation of the alkaloids of the hemlock-namely, coniine, methyl-coniine, y-coniceine, conhydrine, and pseudo-conhydrine, may be effected as follows : The greater portion of the coniine, which forms the chief constituent, is separated by distillation and the residue then fractionated up to 190" C., whereby the conhydrine (m.p. 118" C.) remains as an undistilled residue. The lower fractions are next benzoylated in alkaline solution, and the resulting oil, after dissolving in ether, is extracted with acid to remove therTHE ANALYST. 75 methyl-coniine. The ethereal solution is then concentrated and treated with petroleum spirit (ligroin) to precipitate the benzoyl-amino-butyl-propyl-ketone, which is formed by the action of benzoyl chloride on y-coniceine.The mother-liquor is redistilled and yields benzoyl coniine (b.p. 203'to 204" C. at 16 mm. pressure), and some more of the benzoyl-amino-ketone. Starting with 104 grams of material, the author was able to obtain 1 gram of conhydrine, 7 grams of methyl-coniine, 52 grams of amiho-ketone corresponding with 26 grams of y-coniceine, and 124 grams of benzoyl- coniine, corresponding with 68 grams of coniine, total 102 grams. The coniine recovered from the benzoyl derivative proved to be a mixture consisting of t-coniine and a little d-coniine. The substance described above as methyl-coniine has [.ID 35.66 at 24' C., and appears to be a simple substance.I t yields a picrate melting at 114" C., a platinichloride melting at 195" C., and an aurichloride between 80" and 90" c. w. P. s. The Oleoresin of Pinus Longifolia. F. Rabak. (Pharm. Rev., 1905, xxiii., 229 ; through Phurm. Jour., 1906, vol. 76, 11.)-The oleo-resin of Pinus Zongijolia, a native of the lower Himalayas, is a white, opaque, tough substance showing a partially crystalline structure. A sample examined had a specific gravity of 0.866 and [a],, + 2" 48. I t yielded 18.5 per cent. of essential oil on distillation, the oil having a characteristic pinene odour, and a faint aroma of limonene. On fractionation, dextropinene and laevolimonene were isolated. The residual resin was whitish and brittle ; it had an acid value of 142 and ester value of 13.When dissolved in acetic acid the solution deposited crystals of a resin acid Its odour is lemon-like. melting at 138' to 140" C. w. P. s. A Distinctive Reaction for Euphorbium Resin. A. Tschirch and Paul. (Pharm. Zeit., 1905, l., 561 ; through Pharm. Joum., 1906, vol. 76, 35.)-About 0.01 gram of the resin is treated with 10 C.C. of petroleum spirit, and the mixture filtered. The filtrate is allowed to flow on to the surface of 20 C.C. of sulphuric acid, to which 1 drop of nitric acid has been added. A red-coloured zone is obtained at the junction of the two liquids; on shaking, the acid layer becomes red and, in the course of a day or two, turns brown. w. P. s. Estimation of Formaldehyde in Formaldehyde Pastilles (Trioxy- methylene).Ernst Rust. (Zeit, angew. Chem., xix., 138.)-The author claims the following method of estimating formaldehyde to be superior to the older ones : Two grams powdered trioxymethylene are added to a 250 C.C. Erlenmeyer flask, in the neck of which is fitted a funnel. The solid is washed in with 70 C.C. normal sodium hydroxide solution. To this mixture 9 to 10 grams of 30 per cent. hydrogen peroxide is added slowly at first to prevent undue heating. After standing for two hours the mixture is warmed gently to boiling, to decompose the excess of hydrogen peroxide. The funnel, after being carefully washed with water, is removed, a small excess of normal sulphuric acid solution added, and the mixture titrated back with normal sodium hydroxide solution, using phenolphthalein as indicator. One C.C. of normal sodium hydroxide corresponds to 0.03 gram CH,O. The original substance76 THE ANALYST+ must be tested for alkalies or acids before this method is applied, and these must be taken into account in the final calculation. H. D. L. The Detection of Iodine Compounds in the Dry Way. B. Merk. (Pharm. Zeit., 1905, l., 1022; through Chem. Zeit. Rep., lT5, xxix., 405.)-The substance under examination is rubbed with a little potassium persulpbafe and some soluble starch, the mixture becoming more or less blue in the presence of iodine compounds not containing oxygen : 2KI + K,S20s = 2K2S04 + I,. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9063100072

出版商:RSC    

年代:1906

数据来源: RSC

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76 THE ANALYST. ORGANIC ANALYSIS. Preparation of Pure Ethyl Alcohol. L. W. Winkler. (Berichte, 1905, xxxviii., 3612-3616 ; through Pharm. Joumn., 1905, vol. 76, 12.)-Acetaldehyde is removed from commercial absolute alcohol by allowing the sample to stand over finely-powdered silver oxide for several days, a little potassium hydroxide being also added. The amount of silver oxide required is never more than a few grams per litre, and about 1.2 grams of potassium hydroxide is sufficient to neutralize all the acetic acid resulting from the oxidation of the aldehyde. The mixture should be shaken from time to time. The water present in the alcohol is then removed by heating the latter for several hours over, and finally distilling from, metallic calciumTHE ANALYST. 77 filings, using about 20 grams of the metal per litre.The alcohol so obtained can be once more distilled from metallic calcium. The advantage in the use of calcium over sodium lies in the fact that calcium hydroxide is totally insoluble in alcohol, and therefore as long as the alcohol contains moisture a white precipitate will be formed. The author has made a number of determinations of the specific gravity of pure ethyl alcohol, and has deduced from them the following formula for calculating the specific gravity of alcohol at any temperature from 0" to 30' C. : Specific gravity 0"-30" = 0.80629 - 0*000838t - 0.0000004t~, where 0.80629 is the specific gravity of alcohol in vacuo compared with that of water at 4" C. The boiling-point of pure alcohol was found to be 78-37' C.at 760 mm. pressure. It was observed that absolute alcohol is not so hygroscopic as is commonly imagined ; 200 C.C. of absolute alcohol absorbed less than 0.1 per cent. of water after fifteen minutes' exposure to the air. w. P. s. The Determination of Traces of Benzaldehyde. H. He'rissey. (Joz~cr.12. Pharm. Chim., 1906, xxiii., 60-65.)-Phenylhydrazine reacts with benzaldehyde to form an insoluble phenylhydrazone- C,H,NH.NH, + C,H,.COH = C,H,.CH.N.NH.C,H, + H,O. The reagent used by the author consisted of 1 C.C. of freshly distilled phenylhydra- zine and 0.5 C.C. of glacial acetic acid in 100 C.C. of water. On treating an aqueous solution of benzaldehyde with an equal volume of this reagent, and allowing the mixture to stand for twenty-four hours at 15" to 20' C., there was formed an insoluble crystalline precipitate, which could be collected in a Gooch's crucible, washed with a known quantity of cold water, and dried in a vacuum over sulphuric acid until constant in weight.I t was found, however, that very faint traces of the aldehyde required a very long time for complete combination, and, on the other hand, the results were liable to be too high if the reagent was allowed to act for several days. But by heating the mixture on the boiling water-bath for twenty minutes, and then allowing the liquid to stand for twelve hours before filtration, washilig the precipitate in the Gooch's crucible with 20 C.C. of water and drying it in vacuo, excellent results were obtained, especially when the quantity of phenylhydraaone did not exceed 0.1 to 0.25 gram.C. A. M. On the Determination of Sugar with Fehling's Solution. F. P. Lavalle. (Chem. Zeit., 1906, xxx., 17.)-It is often difficult to determine the end-point of the reaction in titrating a solution of glucose, owing to the cuprous oxide subsiding but slowly, and reflecting its colour to the surface. The author obviates this by adding an excess of alkali, and thus preventing entirely the separation of the cuprous oxide. From 5 to 10 C.C. of Fehling's solution are placed in a 200 C.C. porcelain basin, together with 30 C.C. of sodium hydroxide solution (1 : 3) and 50 to 60 C.C. of water,78 THE ANALYST. and the liquid heated to incipient boiling, and then titrated with the sugar solution, the reaction being complete as soon as the last drop causes the blue colour of the Fehling's solution to disappear.Test experiments are stated to have given very satisfactory results. C. A. M. The Detection and Determination of Trehalose by Means of Trehalase. P. Harang. (Jourrt. Pharm. Chim., 1906, xxiii., 16-20.)-The method is based upon the fact that trehalose (a= + 197" 3 ) is inverted by the specific enzyme trehalase into two molecules of glucose, which will, of course, reduce Febling's solution. Thus, if a 1 per cent. aqueous solution of anhydrous trehalose giving in the polarimeter a reading of a = + 3" 57' be treated with trehalase, the liquid, after complete inversion of the hexabiose, will be found by means of Fehling's solution to contain a quantity of reducing sugar corresponding to 1.052 grams of glucose, and the deviation ( I = 2) will be + 1" 6', a, difference of 2" 51'.If, then, the difference between the rotations calculated from the amount of glucose formed under the action of the enzyme coincides with the polarimetric readings, the presence of trehalose may be inferred, and its amount may be calculated, provided that the enzymic action is complete. In order to obtain the specific enzyme trehalase the author incubates a cultiva- tion of Aspergillus niger on Raulin's fluid at 33' C. until the first signs of fructification (about twenty-four hours). The nutrient fluid is then decanted and replaced with water, and the cultivation allowed to stand at the ordinary temperature for five or six days until fructification appears, the water being renewed every twenty-four hours.The mould fungus is then pressed between filter-papers, finely divided, left for three hours in contact with a fourth of its weight of 95 per cent. alcohol, drained with the aid of a filter-pump, and finally dried in the oven at 33" C . and powdered. This prepara- tion has a strong enzymic action upon trehalose, 0.5 gram being sufficient to invert 1 gram of the sugar in 100 C.C. of water within forty-eight hours at 33" C. Before using the enzyme for the detection of trehalose in mushrooms, etc., it is necessary to eliminate substances such as glycogen, which can also be attacked by it. The fungi are twice extracted, as soon as possible after being gathered, for ten minutes with their own weight of boiling 90 per cent. alcohol, and the united extracts filtered.The filtrate is distilled under reduced pressure until the residue is only 100 C.C. (from 1 kilo of fresh mushrooms). On now adding 4 parts by volume of 80 per cent. alcohol to the residue there is an abundant precipitate, which is left to subside until the next day. The clear liquid is then decanted, and the residue mixed with a few C.C. of water, taken up with 4 parts by volume of 80 per cent. alcohol, and boiled for twenty minutes on the water-bath under a reflux condenser. It is then allowed to cool and the supernatant liquid decanted, united with the washings, and evaporated to dryness in oucuo. Finally, the residue is taken up with water saturated with thymol (100 C.C. for each 200 grams of mushrooms), and this solution treated with enzyme.C. A. M. The Charaeteristies of Certain Animal Fats. C. Schneider and S. Blumenfeld. (Chem. Zeit., 1905, xxx., 53, 54.)-The following physical and chemical values were obtained :ANIMAL. Vikare s e a l (Phoca fa- tida) Vikare seal (Phoca fa- tida) Porpoise (Pho- cans com- munis) Coot (Fulica atra) Crane (Grus cinerea) Lynx ( t y n z europczus) Glutton (Gzdo b o r e:alis) body fat Glutton (GuZo b o r e a 1 i s) kidney fat Bear (UTrsa arctos) 0.9321 0.9336 0.9334 0.9163 0.9222 0.9248 0.9153 0.9230 0,9156 FATS. 87.0 at 20" c. - 62.7 at 25" C. 62-9 at 25" C. 61.5 at 20° c. 70.0 at 20" c. 54.2 at 30" C. 45.2 at 45" c. 60.8 at 20" c. 0.48 1.08 1.2 1.66 9.33 On81 5-84 -- 50.6 188.5 189.0 224.8 192.6 191.2 190.22 193.3 193.3 191-0 191.35 193.3 111.2 87.13 75.25 110.6 54.36 50-82 80 *7 95.6 95.8 85.5 95.2 95 *7 95.8 95.4 95.8 94.5 1.55 0.96 12.1 0.35 0.13 0.43 0.12 - 0.33 FATTY ACIDS. 0,9172 - 0.9121 0-9151 0.9005 0.9412 0.9118 - 0.9347 74.1 at 20° c.- 54.3 at 25' C. 44.7 at 35" c. 40.8 at 30" C. 53.9 at 35" c. 31.9 at 45" c. 31.7 at 45O c. 43.0 at 40" C. 14.0 - - 33.5-34.5 31-0 35.5 40.0-41 *O 40*0-41*0 37.5 13.0-14 0 13.0-14-0 18.0 30.5 29.3 35.0 37.5 - 36.1 198.0 196.0 207.0 - 201.0 202 7 203.4 203.0 203.0 195.3 201.8 126.0 84.8 73.5 111.8 55.5 52.8 '76.580 THE ANALYST. The high Reichert value of the porpoise fat was due to the presence of a considerable quantity of the glycerides of valeric acid. The fat, which was derived from the body, was oily, and had a pale yellow colour. Of the other fats examined, that of the seal was a soft yellow semi-solid; the fats of the coot, crane, and lynx were soft white or light yellow semi-solid masses ; the fat of the glutton was a white, not very hard fat ; and the bear’s fat had the consistency of vaseline at 15O C.I t is pointed out that the iodine valueof the fat of the lynx is the highest yet recorded for land beasts of prey. C. A. M. Determination of the Total Organic Acids in Tobacco. J. Toth. (Ghem. Bit., 1906, xxx., 57,58.) -The method proposedis similar to the one describedpreviously by the author for the, determination of nicotine (ANALYST, 19q2, p. 12). Two grams of the dry powdered tobacco are moistened with 2.5 C.C. of 20 per cent. sulphuric acid, and then mixed with sufficient plaster of Paris to form a dry powder.This is placed in a well-corked cylinder and shaken for forty-eight hours with 100 C.C. of anhydrous ether ; 50 C.C. of the ethereal solution are then drawn off, evaporated slowly, and the residue dissolved in warm water. The solution is now titrated with $ sodium hydroxide solution, using alkanna tincture as indicator (ANALYST, 1903, p. 193), and the result calculated into anhydrous oxalic acid. In thirty-two samples of various tobaccos examined, the writer found from 3.6 to 8.7 per cent. of total organic acids (expressed as oxalic acid), and the quantity of organic acid was found to be propor- tional to the burning quality of the several tobaccos--that is, bad-burning tobaccos contained the most acid. w. P. s. Estimation of Tannin in Crude Products.A. Manea. (Chem. Zeit. Rep., 1905, xxix., 381,)-The principle of the method lies in the fact that when a certain quantity of a tannin solution is added to a mixture of a known quantity of glacial acetic acid and neutral lead acetate of known dilution, the tannin alone is pre- cipitated with the lead, whilst all other substances remain in solution. The author has obtained results which give not more than 0.5 per cent. difference in analyses of the same raw material. E. K. H. Estimation of Caoutchouc. T. Budde. (Chem. Zeit. Rep., 1905, xxix., 393.) -The process recommended, after many experiments, is as follows : A solution of bromine in carbon tetrachloride is used as a brominating liquid, iodine being added as a halogen carrier, the action being then continuous.The proportions used by the author are : 16 grams bromine (6 c.c.) and 1 gram iodine dissolved in carbon tetra- chloride and made up to 1 litre. For the estimation about 1 gram of the sample of caoutchouc is placed in a 100 C.C. flask, covered with carbon tetrachloride, and allowed to stand, with frequent shaking, until the caoutchouc has dissolved, or is evenly divided. The flask is then filled to the mark and well shaken. Ten C.C. are taken for each analysis. This is filtered, if necessary, in an Allihn’s tube and washed with about 50 C.C. CCl,. To the filtrate 50 C.C. of the brominating solution are added, when a jelly-like substance is soon precipitated. After the solution has become clear (quarter of an hour), half its (If the solution is too viscous, it must be diluted.)THE ANALYST.81 volume of alcohol is added ; the liquid is now clear yellow, and the tetrabrom-caout- chouc is transformed into the white form. I t can now be easily transferred to a weighed filter paper, washed first with a mixture of 2 parts carbon tetrachloride and 1 part alcohol, and then with pure alcohol, and dried to constant weight at 60" C. ; 456 grams of tetrabrom-caoutchouc = 136 grams of pure caoutchouc. Caoutchouc resin and oxidized caoutchoucs do not take part in the bromine reaction. The process recommends itself by its simplicity, and especially by the fsct that it give? fhe true content of pure caoutchouc. E. Ei. H. The Direct Determination of the Acetyl and Benzoyl Groups. R. Meyer and E. Hartmann. (Berichte, 1905, xxxviii., 3956.)-From 0.5 to 0.7 gram of the substance is heated with about 5 grams of pure sodium hydroxide and as small a quantity as possible of methyl alcohol which has been purified by distillation with potassium hydroxids. After about an hour the saponification is complete in the case of most acetates, and the solution is then mixed with 50 C.C. of phosphoric acid (specific gravity 1*104), and distilled in a current of steam, a little lime being placed in the vessel in which the steam is generated. In order to determine whether the distillation is complete, portions of the distillate are titrated from time to time after it is thought that the bulk of the acid has passed over. The distillation should be continued until 150 C.C. of the distillate consume not more than 1 or 2 drops of baryta solution, phenolphthalein being used as indicator. The determination of the benzoyl group is carried out in the same way, and gives equally satisfactory resul t s, C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN906310076b

出版商:RSC    

年代:1906

数据来源: RSC

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THE ANALYST. 81 INORGANIC ANALYSIS. Provisional Methods for Copper Lead and Zinc of the Committee .on Uniformity in Technical Analysis of the Western Association of Technical Chemists and Metallurgists. (Chem. Engineer 1905 ii. 287.) Copper.-The iodometric method is used the sodium thiosulphate solution (20 grams per litre) being standardized by dissolving 0.2 to 0.5 gram of copper foil in 5 C.C. of nitric acid and evaporating to 2 or 3 C.C. ; after adding 5 C.C. of hot water and 6 C.C. of ammonia the whole is boiled for a few minutes cooled and diluted to 75 or 80 C.C. After adding 8 C.C. of acetic acid and 10 C.C. of potassium iodide solution (30 per cent.) and well shaking the liquid is titrated with the thiosulphate, 4 or 5 C.C. of starch solution (1 gram per 200 c.c.) being added after the colour has been changed from brown to yellow.To determine copper in ores 0.5 gram of the sample is heated with 2 C.C. of nitric acid 3 C.C. of hydrochloric acid and 4 C.C. of sulphuric acid until white fumes are evolved. After cooling and diluting with 25 C.C. of water the whole is boiled with a piece of sheet aluminium; 10 C.C. of hydrogen sulphide water are then added to insure complete precipitation and the precipitate filtered off washing three times by decantation; 55 C.C. strong nitric acid are then poured over the copper and aluminium ; the aluminium is removed and washed with a little hot water and the filter washed with strong bromine water. The solution is the 82 THE ANALYST. evaporated down to 2 or 3 C.C. ; 5 C.C. of hot water and 6 C.C.of ammonia are added ; the whole is boiled acidulated with 8 C.C. of acetic acid and titrated as above. Lead. - The ammonium molybdate method is used. To standardize the soletion 0.3 to 0.5 gram of lead foil is dissolved in 10 to 15 C.C. of 1.2 nitric acid; 20 C.C. of 1.1 sulphuric acid are then added ; the whole is well stirred and allowed to settle. The liquid is then decanted off through a filter and the precipitate washed three or four times with 2 per cent. sulphuric acid and finally once with cold water. The filter is then washed free from lead sulphate by repeatedly passing 50 C.C. of a hot 20 per cent. ammonium acetate solution through it and finally washing with hot water. The solution is then heated with the main bulk of the precipitate until the latter is dissolved when it is diluted to 200 C.C.made just acid with acetic acid and titrated with ammonium molybdate solution (8.64 grams per litre) until a drop of the liquid gives a yellow colour with a drop of tannic acid solution (1 gram in 300 C.C. water). For ores 0.5 to 1. gram is heated with 10 C.C-of strong nitric acid and 10 C.C. of strong sulphuric acid until white fumes appear, when the liquid is cooled diluted to 50 c.c. boiled and treated as above. To standardize the solution 0.2 t o 0.3 gram of freshly-ignited zinc oxide is dissolved in 10 C.C. of hydrochloric acid and neutralized with ammonia ; 6 C.C. of hydrochloric acid are then added ; the liquid i s diluted to 180 C.C. with water boiled and titrated as follows The solution i s divided into two equal parts; one of these is titrated quickly after which the other part is added and the titration finished by adding nearly enough of the ferrocyanide solution at once to precipitate the zinc and then very carefully adding the solution until a yellow colour is obtained with a drop of uranium acetate solution containing 4.5 grams in 100 C.C.of water. The ferrocyanide solution contains 21.6 grams per litre. For ores 0.5 to 1 gram is dissolved in 4 to 8 C.C. of hydrochloric acid, and an equal amount of nitric acid. The solution is evaporated down to one-third its volume ; any gelatinous silica separated is filtered off and the filtrate evaporated to dryness with 15 C.C. of a saturated solution of potassium chlorate in nitric acid. Without any baking the residue is boiled with 40 C.C.of a solution made by dissolv-ing 60 grams of ammoliium chloride in 250 C.C. of water and 150 C.C. of concentrated ammonia. The precipitate obtained is filtered off and washed with the same ammonium chloride solution ; if much iron is present the precipitate is dissolved in the minimum of hydrochloric acid and reprecipitated with the ammonium chloride solution. The filtrate is neutralized 15 C.C. of hydrochloric acid and 15 grams of granulated lead are added and the whole is boiled until all the copper is pre-cipitated after which the titration is made as above. All the conditions should be the same in all titrations as far as possible. The temperature should always be near the boiling-point. Zinc.-The ferrocyanide method is used.A. G. L. The Volumetric Determination of Lead as Iodate. L. Moser. (Chenz-Zeit. 1906 xxx. 9.)-On treating a solution of a lead salt with potassium iodate in moderate excess there is formed a heavy crystalline precipitate of lead iodate which is nearly insoluble in water and only sparingly soluble in nitric acid but dissolves readily in hydrochloric acid with the formation of chlorine. This lead iodate is THE ANALYST+ 83 much more insoluble than the sulphate and good results can be obtained in analytical determinations based on the reaction. The solution of the lead salt which may con-tain acetic acid or a little nitric acid is treated with a measured quantity of standard potassium iodate solution made up to a definite volume and shaken and the lead iodate allowed to subside.An aliquot portion of the clear supernatant liquid is then titrated with thiosulphate solution after the addition of potassium iodide and dilute sulphuric acid. The excess of iodate thus determined is subtracted from that originally added and the difference corresponds to the amount of lead present, 2 parts of potassium iodate being equivalent to 1 part of lead. In examining commercial sugar of lead 1 gram of the sample is dissolved in wqter mixed with 70 C.C. of decinormal potassium iodate solution and made up to 200 C.C. An aliquot portion (50 c.c.) of the clear supernatant liquid is then treated with potassium iodide and the liberated iodine titrated with standard thiosulphate solution. The amount of iodine found corresponds to the amount of free acid in the sugar of lead.Sulphuric acid is now added and the main quantity of iodine titrated. When the original sample does not yield a clear solution a few drops of acetic acid are added to dissolve basic salts etc. C. A. M. The Rapid Precipitation of Antimony Electrolytically. Julia Lang-ness and Edgar F. Smith (Journ. Arner. Chem. Xoc. 1905 xxvii. 1524.)-In consequence of Fischer and Boddaert’s objections (Zeits. f. Elektrochemie x. 950), the authors have repeated Exner’e work on the deposition of antimony using the rotating anode (ANALYST 1903 xxviii. 330) and they find the method to give excellent results. They used an almost boiling solution of a total volume of 70 c.c. containing 0-24 gram of antimony in either state of oxidation as well as 15 C.C. of sodium sulphide solution (specific gravity 1-18> 3 grams of potassium cyanide and 1 C.C.of 10 per cent. sodium hydroxide. Only 2 grams of potassium cyanide need be added if only 10 C.C. of sodium sulphide solution are present. The current was 6 amperes per 100 sq. cm. at 3.5 to 4 volts the time being fifteen minutes. The method may be applied to the analysis of stibnite the ore being directly treated with sodium sulphide and to the separation of arsenic from antimony. I n six experiments in which 0.1268 gram of antimony and 0.2000 gram of arsenic were present the maximum error on the antimony was 0*0001 gram. A. G. L. The Determination of Bismuth and its Separation from other Heavy Metals. H. Salkowski. (Berichte 1905 xxxviii. 3943 3944.)-It was suggested by the author in 1868 that it would be preferable to determine bismuth in the form of a phosphate rather than as an arsenate and he has now worked out the details of the method.The precipitate can be ignited without fear of reduction and weighed as BiPO,. I t is essential that the solution should not contain hydrochloric acid or chlorides and that free nitric acid should not be present in any considerable quantity. Good results are stated to have been obtained in this way in the separation of bismuth from copper and lead but the details are not described. C. A. M 84 THE ANALYST. The Iodometric Determination of Copper. T. Brown Jun. (Chem. Engineer 1905 ii. 307.)-The method described consists in dissolving from 2.5 to 0.5 gram of the ore in aqua regia evaporating the solution with sulphuric acid, filtering from gangue and lead sulphate and precipitating the filtrate with sodium thiosulphate.In precipitating with thiosulphate the author recommends boiling the liquid for one half hour for high-grade ores and for one hour or even longer for low-grade ores ; if too much evaporation takes place water should be added. The preci-pitate is filtered off washed with hot water and roasted to oxide at a dull red heat. The copper oxide obtained may contain antimony bismuth and silver. It is placed in an 8-ounce flask nitric acid water and about 0.5 gram of potassium chlorate are added and the whole is boiled down to about half its original volume. Should any chlorate become decomposed a little water is added and the chlorine liberated boiled off.After cooling a little water and a slight excess of ammonia are added and the whole is boiled again for a few minutes; this treatment insures a more distinct end-point. The solution is then acidified with acetic acid the determination finished as usual with potassium iodide and standard thiosulphate solution. A. G. L. Analysis of Tungsten-Tin Minerals. Henri Angenot. (Zeit. angew. Chem., xix. 14O.)-On account of the extreme difficulty experienced in the estimation of stannic oxide and tungstio acid in presence of each other the author has introduced the following modification of the Borntrager method One gram of the finely powdered mineral is carefully fused with sodium peroxide in an iron crucible for a quarter of an hour. This is digested with water and made up to 250 C.O.If lead be present it must be separated with carbon dioxide and the mixture finally filtered. One hundred C.C. of the filtrate are treated with a mixture of 15 C.C. nitric acid and 45 C.C. hydrochloric acid and then evaporated to dryness. The residue is dissolved in a mixture of 100 grams ammonium chloride 100 grams hydrochloric acid and 1,000 C.C. water and filtered. The undissolved tungstic acid is dissolved in warm ammonia and the process repeated and the insoluble product finally ignited. Two to three grams of zinc are added and the whole allowed to stand for one hour at 60" C. then filtered from the precipitated oxide of tungsten and the filtrate treated with sulphuretted hydrogen to remove the tin which is weighed as sulphide. A second 100 C.C.is used for the estimation of the tin. H. D. L. The Separation of Iron from Zinc. V. Komar. (Chem. Zeit. 1906 xxx., 31 32.)-The zinc and iron salts are converted into sulphates dissolved in sulphuric acid (specific gravity 1*3) and the solution oxidized by the addition of a little nitric acid. The mixture is then evaporated at first on the water-bath then on the sand-bath and the residue finally heated over a free flame care being taken to avoid crepitation. After igniting at a dull-red heat the residue is dissolved in water and the ferric oxide collected on a filter washed and weighed Zinc sulphate does not decompose at a temperature of 700" C. or more. w P. s THE ANALYST. 85 Standardizing Potassium Permanganate for Iron Determinations. Richard K.Meade. (Chem. Engineer 1905 ii. 281.)-As a standard for permanga-nate solutions the author prefers to use pure electrolytic iron. This is obtained by electrolysing in a glass beaker a solution containing 0.5 gram of iron as pure ferrous or ammonium ferrous sulphate dissolved in 250 C.C. of saturated ammonium oxalate solution. The anode is formed of a centrally-placed piece of platinum wire the cathode consisting of two pieces of platinum foil 18 inches square. A€ter electrolysing for two hours with a current of from 0-5 to 0.7 ampere about 0.15 gram of iron will be deposited on each piece of foil. After weighing each piece is dissolved separately in a mixture of 500 C.C. water and 50 C.C. of sulphuric acid which has been previously boiled for some time whilst a current of carbon dioxide was led through it.The flask and the dissolved iron are allowed to cool in the current of carbon dioxide and titrated as usual. Proceeding in this way it is found that the iron value of apparently pure iron wire is often above 100 per cent. A. G. L. The Use of Ammonium Persulphate in the Determination of Chromium in Steel. Harry E. Walters. (Journ. Amer. Chem. Soc. 1905 xxvii. 1551 ; and Proc. Eng. Soc. West Pennsylvania 1905 xxi. 465.)-The method consists in determining chromium and manganese together after oxidation by ammonium persulphate by means of ferrous sulphate and determining the manganese separately by means of sodium arsenite 1.25 grams of the sample are dissolved in 35 C.C. dilute sulphuric acid (1 5 ) a small amount of ammonium persulphate being added to oxidize the iron and carbonaceous matter ; the liquid is diluted to 100 c.c.40 C.C. of silver nitrate solution (containing 0-16 gram of the salt) and then 5 to 7 grams of slightly moist ammonium persulphate are added and the whole is boiled for five minutes after which the liquid is cooled and made up to 500 C.C. On 100 C.C. of this solution the manganese is then determined by titrating in a porcelain dish with sodium arsenite solution made up according to Blair and standardized against a chrome steel of known manganese content. To the remaining 400 C.C. a measured volume of ferrous sulphate solution (22.5 grams of ferrous sulphate and 50 C.C. of strong sulphuric acid per litre) is added and the excess of ferrous sulphate deter-mined with standard permanganate solution (1.82 grams of the salt per litre).The latter may be standardized against iron or against a pure chromium salt ; it should be compared with the ferrous sulphate solution every day. Test results obtained in this way on pure solutions containing iron manganese and chromium and on chromium steels are excellent for both the manganese and chromium. If tungsten or molybdenum is also present a carbide of chromium insoluble in sulphuric acid, may be left which requires fusion with sodium carbonate. If vanadium is present, the manganese cannot be determined by sodium arsenite ; in this case the bismuthste or Ford’s method may be used. A. G. L. Estimation of Chromium and Manganese. A. Kleine. (Chem. Zed. Rep., 1905 xxix. 380.)-Five grams of steel shavings are dissolved in 500 C.C.HCl (1.12) by the aid of heat the solution is heated to boiling and all subchlorides converted into perchlorides by adding 3 C.C. of HNO (14) drop by drop. The solution is the 86 THE ANALYST. evaporated to a syrup and the iron extracted by shaking with ether. The iron-free solution is evaporated to dryness the residue taken up by 10 C.C. sulphuric acid (1 lo) the solution diluted treated with ammonium persulphate (60 grams per litre) and boiled for fifteen to twenty minutes. The precipitated manganese peroxide is filtered off and washed. The chromium is estimated in the filtrate by adding excess of iron sulphate solution (50 grams FeSO in 800 C.C. H,O + 200 C.C. H,SO,), and the excess titrated with standard permanganate solution.The iron titre of the permanganate x 0.31 gives the chromium titre. The washed manganese precipitate is then transferred to the precipitation flask 10 C.C. of sulphuric acid added and sufficient oxalic acid solution run in to completely dissolve the precipitate. The excess of oxalic acid after dilution with 200 to 300 C.C. of hot water is estimated by per-manganate. To obtain the manganese titre of the permanganate the iron titre must be multiplied by 0.501 (according to Ledebur) and not by the older value 0.491. For crude iron and difficultly soluble chromium steel 5 grams of the metal should be dissolved in 50 C.C. of HCl+5 C.C. HNO ; the solution is then diluted, filtered from silica evaporated and shaken up with ether and treated aB above.For steel with a high percentage of chromium the filtrate from the manganese pre-cipitate should be made up to 500 C.C. and the chromium estimated in an aliquot part . E. K. H. The Ford-Williams Method for High-grade Manganese Ores. J. James Skinner. (Chem. Engineer 1905 ii. 279.)-0.5 gram of the ore is digested with 20 C.C. hydrochloric acid until the residue is white after which the solution is evaporated down to a syrup. I t is then boiled with 110 C.C. nitric acid until the red fumes are almost wholly driven off when half a teaspoonful of fine asbestos fibre is added carefully and boiling continued for one minute more when 8 grams potassium chlorate are added and the whole boiled for another ten minutes. The precipitate is then filtered off as usual on an asbestos filter Precipitate and filter are then dropped into a beaker containing 0.750 gram of pure oxalic acid 50 C.C.of dilute sulphuric acid and 150 C.C. of warm water. After gently warming until the whole of the manganese dioxide has dissolved the liquid is titrated with standard potassium permanganate with which another portion of 0.750 gram oxalic acid is also titrated, the difference corresponding to the manganese. For ores containing manganese in a form insoluble in hydrochloric acid the insoluble portion is filtered off treated with hydrofluoric and sulphuric acids and, after evaporating off the hydrofluorio acid dissolved in hydrochloric acid and added to the main solution. A. G. L. A New Reagent for Potassium. E. P. Alvarez. (Gazx. Chim. ItaE. 1905, xxxv.463; through Chem. ,Yeit. Rep. 1905 xxix. 404 405.)-The reagent consists of a saturated (5 per cent.) solution of amido-naphthol sulphonic acid, C,H5$0H(2 N=,W SO,Na(G). It should be prepared with recently-boiled cold water shortly before it is requiredfo THE ANALYST. 87 use. It can only be kept in black bottles from which the air is carefully excluded. The precipitate of potassium amido-naphthol-sulphonate is given by all potassium salts including the iodide provided the solution be neutral. Ammonium salts and magnesium salts in the presence of ammonium chloride are not precipitated by the reagent. Solutions of potassium salts of the strength of 5 to 10 per cent. give the reaction almost immediately; those containing from 3 to 5 per cent. do not give a precipitate until after ten minutes; and those coGtaining 1 per cent.not until after several hours. C. A. M. Colorimetric Estimation of Selenium. J. E. Clenell. (Chem. Zeit. Rep., 1905 xxix. 392.)-The selenium must be brought into solution as selenite or selenate ; this can be effected by treatment with concentrated nitric acid and subsequent addition of hydrochloric acid ; the free chlorine must then be driven off. A white precipitate in the solution is of no account and may if necessary be produced in the comparison test by precipitating zinc chloride with potassium ferrocyanide. The solution is heated to boiling and a few C.C. of a 5 per cent. solution of sodium bisulphite added. In case of cyanide solutions 100 C.C. boiled with 10 C.C. HCl for five minutes give the precipitate of selenium without any addition of sulphite.The finely divided selenium remains some time in suspension and the tint it gives is compared with that of known amounts of a standard solution prepared by shaking 0.1 gram selenium with strong bromine water until dissolved adding bicarbonate gradually until a colourless solution is obtained and making up to a litre. The standard tests are boiled with 5 to 10 C.C. of sodium bisulphite as before. The only element which interferes with this process is copper which with potassium ferrocyanide gives a colour similar to that of the suspended selenium. The estimation takes about fifteen minutes. E. K. H. The Use of the Rotating Anode and Mereury Cathode in Electro-analysis. Second Paper. Lily G. Kollock and Edgar F.Smith. ( J o ~ ~ ~ . Amer. Chem. Soc. 1905 xxvii. 1527.)-Continuing their work the authors have applied the rotating anode and mercury cathode to metals other than those dealt with in their first paper (ANALYST 1905 xxx. 413). The apparatus used was the same as before except that the weight of mercury used was increased to 60 or 70 grams. For cadmium good results were obtained by electrolysing 5 C.C. of solution containing 0.9480 gram of cadmium as sulphate and & C.C. of concentrate sulphuric acid for fifteen minutes with a current of 3.5 amperes and 10 to 7 volts. For tin the best results were obtained with 10 C.C. of solution containing 0-8212 gram of tin as stannous sulphate and 0-5 C.C. of sulphuric acid using a current of 5 ampere and 5 to 4 volts for eight minutes.For silver the best results were obtained with 5 C.C. of solution containing 0.2340 gram of silver as nitrate and + C.C. of nitric acid, using a current of 4.5 to 3 amperes at 6.5 to 6 volts for five minutes and giving the anode the high speed of 1,200 revolutions per minute. No nitric acid was reduced and hence no ammonium was found in the amalgam. For mercury 5 C.C. of solution containing 0.3575 gram of mercury as mercurous nitrate and 0.02 C.C. of nitric acid gave the best results with a current of 3 amperes and 7 to 5 volts for three minutes 88 THE ANALYST, diluting the liquid to 25 C.C. increased the time necessary to eight minutes. For bismuth the best conditions were Volume 12 C.C. ; bismuth as sulphate 0.2213 gram ; 0.5 C.C.of sulphuric or nitric acid ; current 3 or 4 amperes at 5 to 5-75 volts ; time fifteen minutes for sulphuric and twelve minutes for nitric acid solutions. The platinum wire used as anode should be very smooth in order that the bismuth peroxide at first deposited on it may be readily dissolved. Experiments to determine halogens in metallic haloid salts by using a silver-coated rotating anode proved unsuccessful some of the deposit always becoming detached. It was found possible however to determine the metal in such salts the free halogen being suppressed by adding 10 C.C. of toluene to the liquid. The most favourable conditions found are summarized in the following table : Metal. A s Chloride : Cobalt Gold Ferric Mercuric Stannous Ditto As Bromide : Cadmium Amount taken (gram).- ._. 0.1050 0.1200 0.1030 0.2525 0.0800 0 1600 0.2212 Volume of Liquid (c.c.). ______ 5 5 5 5 5 10 5 AmpBres. 2 to 4 2 to 3 2 to 4 1 to 3 2 to 3 2 to 3 Volts. 5 10 9 10 to 7.5 7 to 6 7 to 6 2 5 Tinie (minutes). 7 5 12 10 10 15 10 Maximum Error (gram). t 0.0002 - 0*0002 - 0 0005 - 0*0001 + 0*0006 - 0*0005 + 0*0003 The anode was not attacked in these experiments ; xylene may be used instead of toluene which is probably converted into a mixture of 0- and p - chlortoluene. It was also found possible to separate iron quantitatively in this way from uranium aluminium thorium lanthanum praseodymium neodymium cerium and zirconium. The quantity of iron present was 0.12 to 0.18 gram and of the sulphate of the other metal 0.1 to 0.5 gram.The volume of the liquid varied from 6 to 10 c.c. the quantity of free sulphuric acid from 0 to $= c.c. the current from 2 to 5 amperes at 9 to 5 volts and the time from fifteen to twenty-five minutes. The maximum error in twenty-nine experiments was -0.0008 gram iron. The metals were used in the form of sulphates. A. G. L. Estimation of Vanadium. W. Heike. (Chem. Zed. Rep. 1905 xxix. 392.) -A comparison of four methods for purposes of technical iron works : 1. The ore is fused with sodium potassium carbonate extracted with hot water, filtered the filtrate acidified with H,S04 the vanadic acid reduced to vanadic oxide with zinc and the amount estimated by titration with standard permanganate.The vanadium titre =iron titre x 0.035. 2. The ore is dissolved the iron extracted by shaking out with ether the solution treated with H202 and the vanadium estimated by comparing the tint (yellow-red) with that of known vanadic solutions THE ANALYST. 89 3. Ledebur dissolves the iron etc. in diluted hydrochloric acid separates the chromium and vanadium from iron and manganese by neutralizing with the barium carbonate fuses the residue with sodium carbonate and nitre and extracts the chromates and vanadates with hot water. The solution is then reduced with alcohol and hydrochloric acid the chromium precipitated with ammonium phosphate and ammonia the vanadium transformed by ammonium aulphate into the sulphide and precipitated as sulphide with acetic add.4. Campagne extracts the iron with ether (as in a) reduces the vaaadic acid by evaporation with hydrochloric acid to V,O, displaces the hydrochloric acid by sulphuric acid warms to 60' to 70° dilutes to 300 c.c. and titrates with potassium permanganate. On heating vanadic acid is obtained. The vanadium titre here =iron titre x 0,914, The author obtained the following figures : I. 11. 111. IV. - 0.11 Iron ore . . Fresh slag . . . 1-40 - - 1.46 Steel with 0.02 Cr. . . - 0.24 0.27 0.54 Steel . . . . - 0.42 0.54 0.54 He concludes by stating that Campagne's method is very suitable for estimation of ferrovanadium especially where chromium is not present in large quantity, otherwise Ledebur's method is to be preferred. . 0.07 -Gray crude iron with 0.14 Cr.0.15 - 0.21 0.21 E. K. H. Moisture and Water of Constitution in Bauxite. H. Lienau. (Chem. Zeit. 1905 xxix. 1280.)-The view has often been expressed that the moisture in bauxites must be estimated by drying in the desiccator and not in the oven as the water of hydration begins to come off even at 100' C. The powdered bauxite was wetted with 14 to 15 per cent. of distilled water and five samples of 10 t o 15 grams were placed in stoppered weighing bottles and dried for ten hours at looo, allowed to stand overnight in a desiccator and weighed. They were then dried for ten hours at IIO' allowed to stand as before and again weighed. This was repeated for temperatures of 150" and 200". It might then be supposed that a characteristic gap would occur between the loss of the moisture and that of the water of constitu-tion.As a matter of fact for most kinds of bauxite no such gap could be dis-tinguished but the loss of water was continuous with rise of temperature until the whole of the water of hydration was evolved and a constant weight obtained at bright red heat. The term '' bauxite " includes materials of very different constitution but the French varieties at least (on which the experiments were performed) can be divided into two great classes (1) The diaspore group containing alumina monohydrate and (2) the true bauxite group containing alumina dihydrate. The author gives figures for both classes for which reference must be made to the original. The conclusions arrived at may be summarized as follows : For the monohydrate group which forms about 90 per cent.of commercial bauxites the weight alters evenly up to 200' c. but SO slowly that the loss in weight The author performed experiments to test this view 90 THE ANALYST between 100" and 200" is only 0.09 per cent. I t is not possible to say at what point the combined water begins to be given off but it is probably fair to assume that there is no more adherent moisture at llOo as the loss between 100' and l l O o = O 02 whilst loss between 110"snd 15O0=0*03'pr cent. This is further made more likely by the behaviour of the dihydrate group. One specimen of this class from Maussane near Arles showed a distinct gap between the two kinds of water the weight remaining constant between 110" and 150".The author considers this characteristic and thinks that in these bauxites the water of hydration only begins to come off after all the adherent moisture has been driven off. The author concludes that in all bauxites the total loss in weight up to 110" C . may be taken as adherent moisture. E. K. H. Volumetric Estimation of Sulphates in Presence of Thiosulphates etc. 0. Huber. (Chem. Zeit. 1905 xxix. 1227.)-The author investigated the process originally brought forward by Miiller and Durkes for the volumetric estimation of sulphates with benzidin hydrochloride and extended it to the estimation of sulphates when thiosulphates sulphites and sulphides were also present. The only modifica-tion made was the substitution of caustic potash for caustic soda. The author gives figur3s which show an error of about 2 per cent.in vahe for total sulphate and states that this process is inaccurate for the following reasons :-The use of so many titrations the errors of which may all lie in the same direction but chiefly in the author's opinion through the defects of the benzidin process itself. He concludes that the chief factor in rendering the process inexact is the great solubility of the benzidin sulphate whilst the absorption phenomena noted by Muller and Durkes are less important. For further details and the figures given reference must be made to the original. E. K. H. Estimation of Sulphuric Acid by Means of Barium Chloride in the Presence of Disturbing Substances. G. Lunge and R. Stierlin. (Zeit. nngew. Chem. xviii. 1921.)-The authors come to the conclusion that the precipita-tion of barium chloride as sulphate is by no means complete in the presence of many salts.Thus if sodium potassium or ammonium salts are present part of the barium sulphate is held in solution. Zinc and copper compounds may however be present without disturbing the reaction in any way. This undesirable influence is negligible however if the precautions suggested by Lunge (Zed. anal. Chem. 1881, Vol. xix. p. 149) are adhered to. H. D. L. The Determination of Nitrous and Nitric Acids. J. Meisenheimer and F. Heim. (Berichte 1905 xxxviii. 3834-3837.)-This method which is claimed to give rapid and accurate results in the simultaneous determination of nitrous and nitric acids is based upon the following reactions : HNO,+HI=NO+I+H,O HNO + 3FeC1 + 3HC1= NO + 3FeC1 + 2H20 THE ANALYST.91 The slightly alkaline solution of the substance (0.1 to 0.2 gram of nitrite) is placed in a round-bottomed 50 C.C. flask closed by an indiarubber stopper with three openings. One of these receives a thistle funnel with a stop-cock; the second holds a delivery-tube the outside portion of which dips into a trough containing a 12 per cent. solution of sodium hydroxide ; whilst the third receives a tube for the introduction of a current of carbon dioxide. The air is first swept out of the flask by means of this gas for about ten minutes after which a eudiometer filled with sodium hydroxide solution is fixed above the delivery-tube and then by means of the funnel the tube of which has previously been filled with water up to the stopcock there are intro-duced 10 to 15 C.C.of a 5 per cent. solution of potassium iodide followed by the same quantity of dilute hydrochloric acid added little by little. When the evolution of gas slackens the contents of the flask are heated to incipient boiling and the last portions of nitric oxide expelled by means of a current of carbon dioxide. The amount of gas contained in the eudiometer is then measured in the usual manner. For the determination of nitrates in the residue from 10 to 20 C.C. of a con. centrated solution of ferrous chloride acidified with hydrochloric acid are introduced into the flask and the gas collected as described in Spiegel’s modification of the method of Schulze and Tiemann (Berichte 1890 xxiii.1361). C. A. M. The Determination of Nitrous Acid. F. Raschig. (Berichte 1905 xxxviii., 3911-3914.)-The method described by Meisenheimer and Heim (see preceding abstract) has been applied by the author to the determination of nitrous acid in solu-tions containing also hydroxylamine but instead of measuring the nitric oxide in a eudiometer he titrstes the separated iodine a determination being made in five to ten minutes. The solution (about 100 c.c.) is placed in a 200 C.C. conical flask into which are then introduced 5 to 10 C.C. of a 10 per cent. solution of potassium iodide. A current of carbon dioxide is now admitted through a tube passing nearly to the bottom of the flask and after two or three minutes about 1 C.C. of sulphuric acid is poured down the side of this tube and the mixture allowed to stand for two minutesh and then titrated with the standard thiosulphate solution which is also made to run down the side of the tube.The bubbles of gas evolved cause the liquids to mix and thus the flask need not be shaken which would cause oxidation of the escaping nitric oxide. In the author’s opinion nitrosyl iodide (NOI) is first formed on adding the acid, and this is then decomposed so that it is necessary to wait for a time before hitrating the solution; otherwise the results will be too high. The author prefers the sul-phanilic acid and permanganate methods where possible but they cannot be employed in the presence of hydroxylamine. As regards the permanganate method he uses an excess of at least 20 per cent. of & permanganate solution into which the solution under examination is poured.The mixture is acidified ii required and allowed to stand for two minutes when the whole of the nitrous acid will have been oxidized to nitric acid. The liquid is then treated with 5 C.C. of a 10 per cent. solution of potassium iodide which dissolves any manganese peroxide and the liberated iodine titrated with, standard thiosulp hate solution. C. A. M 92 acid. In very dilute so-THE in acetic acid. ANALYST. of meta~hos~hate. Insol. The Reactions of the three Phosphoric Acids. C. Arnold and G. Werner. (Chem. Zeit. 1905 xxix. 1326 1327.)-The authors have tested all the reactions described in chemical text-books as means of distinguishing between the three phosphoric acids and have found that in nearly every instance they are unreliable.They have therefore made a new series of tests with the alkali salts of the acids and the principal results obtained are summarized in the following table : REAGENT. Barium chloride . Calcium chloride . . . Nagnesium sulpha te Magnesia mixture . . . Aluminium sulphate Chromium sulphate Ferrous sulphate . . . Ferric chloride . Manganese sulphate Zinc sulphate . Cobalt nitrate . . . Nickel sulphate . . . O~~THOPHOSPHORIC ACID. White ppt. Insol. in ex-cess of alkali phosphate. Sol. in acetic acid. Sol. in NH,Cl. White ppt. Insol. in ex-cess of phosphate. Sol. in acetic acid. Sol. in much NH,Cl. Whitc flocculent ppt. In-sol.in excess ofphosphate and in excess of MgSO,. Sol.in acetic acid. White crystalline ppt. In-sol. in excess ofphosphate and of reagent. Readily sol. in acetic acid. White ppt. Sol. in excess of phosphate and in acetic acid. Greenish ppt. Insol. in excess of phosphate. Sol. in acetic acid. Green ppt. Insol. in ex-cess of phosphate. Yellow ppt. Insol. in ex-cess of phosphate. Sol. in HCl. White ppt. Insol. in excess of phosphate. Presence of much pyro-phosphate prevents ppt. White ppt. Insol. in ex-cess of phosphate. Sol. in NH and in acetic acid. Metaphosphate does not prevent ppt. Blue ppt. Insol. in excess of phosphate. Sol. in acetic acid. Greenish-white ppt. In-sol. in excess of phos-phate. $ol.in acetic acid. PYROPHOSPHORIC ACID. White ppt. Insol. in ex-cess of alkali pyrophos-phate.Insol. in acetic acid. Insol. in NH,Cl. White ppt. Scarcely-sol. METAPHOSPHORIC ACID. White ppt. Sol. in excess of alkali metaphosphate. Insol. in acetic acid. In-sol. in NH,Cl. White ppt. Sol. in excess of metaphomhate. In-of py;iphosphate. Insol. in acetic acid. Dirty-white ppt. Insol. in excess of pyrophosphate and in acetic acid. White ppt. Sol. in excess of pyrophosphate. White ppt. Hardly sol. in excess of pyrophos-phate. Sol. in HC1. White ppt. Hardly sol. in excess of pyrophos-phate. White ppt. Sol. in excess of pyrophosphate. Sol. in NH,. Insol. in acetic acid. Metaphosphate does not prevent ppt. Rose mt. Sol. in excess in acetic aci& Dirty white ppt. Sol. in excess of metaphosphate.Insol. in acetic acid. White ppt. Sol. in excess of metaphosphate and in much HC1. White ppt. Readily sol. in excess of metaphosphate. Rose ppt. Sol. in excess of metaphosphate. Insol. in of pir'ophosphate. Insol. in acetic acid. acetic acid. Greenish-white ppt. Sol. in excess of pyrophos-phate. Sol. in acetic acid THE ANALYST. 93 REAGENT. Uranium nitrate Silver nitrate . W 0 2 ) (NO,), Lead acetate . . . Mercurous nitrate . . . Mercuric chloride . . . Alkaline bismuth so-lution Copper sulphate . Cadmium sulphate . . . ORTHOPHOSPHORIC ACID. Yellow ppt. Insol. in ex-cess of phosphate. Yellow ppt. Insol. in ex-cess of phosphate. Sol. in HNO and NH,. White ppt. Insol. in ex-cess of phosphate. Sol. in KOH and HNO,. Sol.in hot dilute HCI. SoLinmuch tartaricacid. Yellowish-white ppt. In-sol. in excess of phos-phate. Sol. in HNO,. Immediate yellow ppt. In concentrated solution yellow turbidity and deep violet-red ppt. after some hours. -Greenish-blue ppt. Insol. in excess of phosphate. Sol. in NH and acetic acid. White ppt. Insol. in ex-cess of phosphate. Sol. in NH and in acetic acid. PTROPHOSPHORIC ACID. White ppt. Sol. in excoss of pyrophosphate. White ppt. Insol. in ex-cess of pyrophosphate. Sol. in HNO and NH,. White ppt. Sol. in excess of pyrophosphate and in KOH HNO, hot dilute HC1 and much tartaric acid. White ppt. Sol. in excess of pyrophosphate. Sol. in very much HNO,. In concentrated solution red fluorescent turbidity after a few minutes.Then reddish-brown ppt. Bluish-white ppt. Sol. in excess of pyrophosphate and NH,. Insol. in acetic acid. White ppt. Insol. in ex-cess of pyrophosphate. Sol. in NH,. Insol. in acetic acid. METAPHOSPHORIC ACID. White. ppt. Sol. in excess of metaphosphate. White ppt. Sol. in excess of metaphosphate. Sol. in HNO and NH,. White ppt. Sol. in excess of metaphosphate in KOH HNO, and hpt dilute HC1. Insol. in tartaric acid. White ppt. Sol. in ex-cess of metaphosphate. Hardly sol in HNO,. White ppt. (also in presence of ortho- and pyrophos-phate). Sol. in excess of metaphosphate. White ppt. Sol. in excess of metaphosphate. Sol. in NH,. Insol. in acetic acid. For the detection of metaphosphoric acid in the presence of the other two acids the authors consider the reactions with alkaline bismuth solution (vide supra) and with cobaltamine solution particularly suitable.The latter reagent is prepared by mixing equal parts by volume of solutions of a cobaltous salt and an ammonium salt adding a few drops of ammonium hydroxide and shaking the solution until it becomes per-ceptibly brown. It gives a brownish-yellow precipitate with a metaphosphate even when only present in traces in ortho- and pyrophosphates. Pyrophosphoric acid in the presence of the other acids is best identified by its behaviour with copper sulphate and zinc sulphate in acetic acid solution. C. A. M. Estimation of Phosphoric Acid in Thomas Meal Bone Meal etc. 0. Bottcher. (Chem. Zeit. 1905 xxix. 1293.)-1.Estimatiort of Citric Acid Sohbk Phosphate an Thomas lWeaZ.-The author maintains against various critics that 8s agreed upon by the Union of Agricultural Research Stations (in Germany) the $0~-phate can be directly precipitated without error with magnesia mixture containing citrate without previous separation of silica by evaporation with hydrochloric acid, even in cases where a high percentage of silica is shown by a preliminary test. The process gives accurate results so long as the essential condition is observed that al 94 THE ANALYST. the operations are carried through successively without interruption. If the citric acid extracts or the precipitations with citrate-containing magnesia mixture are allowed to stand for hours considerable quantities of silica may come down with the phosphate precipitate and cause a too high result.The separation of silica is always indicated by the bad filtering property of the solution and this serves as a valuable check on the purity of the precipitate. The author has carried out analyses on over 800 samples of Thomas meal in the last year and in no ca6e encountered this complication. The author gives figures which show very exact agreement between the results obtained by this direct estimation and those obtained by first separating the silica. 2. Estimation of Total Phosphate irt Thomas Meal Bone Meal etc.-The author again defends the process prescribed by the Union of Agricultural Research Stations : (1) Against the criticism of V. Schenke who finding 0.3 to 0.4 too little phosphoric acid by this method as against the molybdate method recommended approximately neutralizing the strongly acid solution before precipitation ; and (2) against those analysts who consider that extraction with aqua regia gives less reliable results than extraction with sulphuric acid partly because the compensation in the aqua regia solution varies with the kind and amount of bases present and partly because all the organic acids are not decomposed by the aqua regia so that the calcium salts of these acids accompany the precipitate being insoluble in ammonium citrate solution, the author gives figures of comparative analyses which show that the modifications suggested by these criticisms make no appreciable difference and that the Union process is quite satisfactory.E.K. H. The Determination of Tellurous and Telluric Acids. A. Berg. (Bull. Soc. Chim. 1905 xxxiii. 1310-1312.)-The author’s method depends upon the facts that these acids are readily converted into tellurium chloride by the action of gaseous hydrochloric acid and that the chloride formed can easily be sublimed. The apparatus required is a combustion tube of hard glass the front part of which is bent at a right angle and drawn out to a fine opening which is directed downwards and connected with two small U-tubes containing water. The tube is placed in a combustion furnace and its other end connected with an apparatus giving 8 current of hydro-chloric acid gas. The substance to be analysed is placed in a porcelain boat whicZl is introduced into the tube. The air is swept out by means of a moderate current of the gas and the tube rapidly heated to a temperature below red heat.The tellurium chloride which sublimes on the tube is driven forward by the application of a Bunsen burner. If the process is properly carried out no white fumes should be seen in the absorption tubes and the liquid in the second tube should remain colourless. When the reaction is complete the yellow solution of tellurium chloride is transferred to a weighed porcelain crucible and after the addition of 5 C.C. of nitric acid evaporated slowly on a sand bath. The presence of this nitric acid prevents the volatilization of the tellurium chloride. When the evaporation has proceeded to dryness the residue must be cautiously heated so as to decompose all the tellurium nitrate without fusing the tellurous acid,,part of which would then escape with the nitrous vapours.The residue is then weighed as tellurous anhydride. When metallic tellurites or tellurates are to be With a little care this can readily be done THE ANALYST 95 analysed the residue of chloride left in the boat can be weighed directly. In a test experiment 58.66 per cent. of tellurous anhydride was found as compared with the theoretical 58.26 per cent. A barium tellurite containing according to theory 60.94 per cent. of tellurous anhydride was found to contain 60.28 per cent. The method is obviously only applicable in the absence of compounds of substances such as mercury or chromic acid which yield readily volatile compounds under these conditions.C. A. M. The Volumetric Estimation of Cyanates. A. C. Cumming and Orme Masson. (Chesn. News 1906 vol. 93 pp. 5 and 17.)-A known volume of the cyanate solution is first of all titrated in the cold with etandard acid using congo-red or methyl orange as indicator; the first end-point obtained should be taken. This gives the quantity of carbonate present carbonate being always contained in cyanate solutions. An excess of the acid is then added and the liquid boiled for a few minutes when the cyanate is hydrolysed according to the equation : KCNO+2HC1+H2O=KC1+NR,C1+CO,. The liquid is then cooled and the excess of acid titrated back with standard alkali the quantity consumed being calculated to cyanate. As a further check the ammonia formed may be determined by boiling the'liquid for some time with an excess of standard alkali and titrating back.The method appears to give good results. If cyanide is present it is determined by means of standard silver nitrate, and allowed for in calculating the results. Ferrocyanide in small quantities does not interfere. The solutions used should be rather dilute as otherwise the acid might act on the cyanate in the cold and render the first end-point indefinite. A. G. L. Determination of Cyanides in Crude Coal-Gas. (Chem. Trade JOUY. 1906, xxxviii. 72 73.)-In the proposed method the cyanides are absorbed by freshly precipitated ferrous hydroxide suspended in sodium hydroxide solution. This is prepared by dissolving 4 grams of crystallized ferrous sulphate in 500 C.C. of water a t a temperature of 80' C.adding 4 grams of sodium hydroxide dissolved in water also at 80" C. and boiling the mixture. The precipitate is allowed to settle washed by decantation,' and then mixed with 250 c.c. of 4 per cent. sodium hydroxide solution. Water is finally added to make the volume up to about 800 c.c. and the mixture transformed to an absorption apparatus which consists of a tall glass jar closed at the top with a caoutchouc stopper perforated by two holes. The central one of these carries a length of half-inch solid-drawn nickel tubing reaching to the bottom of the cylinder and upon which are brazed twelve perforated nickel cones. Ten cubic feet of gas are usually sufficient for one test and this volume is passed through the apparatus at the rate of 5 cubic feet per hour.At the end of the operation the contents of the cylinder are washed out into a litre flask and diluted to the mark, h known volume of this solution is then boiled to expel ammonia then treated with sodium plumbate to remove sulphide (in this operation free sodium hydroxide The liquid should fill the cylinder up to the base of the topmost cone 96 THE ANALYST. must be present) made up to the correct volume and the amount of ferrocyanide formed determined in it. w. P. s. Purification of Hydrochloric Acid from Arsenic. (German Patent Apoth. Zeit. xx. 932 ; through Pharm. Jozcr. 1905 lxxv. 910.)-Vanadous salts rapidly reduce arsenious cbloride to metallic arsenic which separates from the solution in the form of minute particles or as a flocculent precipitate which can easily be filtered off.On a large scale the hydrochloric acid gas is passed through earthen-ware vessels containing a concentrated solution of vanadous chloride which retains the arsenic and is simultaneously oxidized to vanadic chloride. The latter can be reconverted into vanadous chloride. w. P. s. A New Method of Determining the Strength of Iodine Solutions. Sig-mund Metzl. (Zeits. anorg. Chem. 1906 xlii. 156.)-The author proposes to standardize iodine solutions used for titrating antimony compounds by means of tartar emetic either as the crystallized salt KSbO(C,H,O,) + H,O or in the anhy-drous condition. The tartar emetic is dissolved in hot water containing tartaric acid, a trace of solid phenolphthalein and an excess of sodium carbonate are added after which GO is led through the liquid until the red colour is destroyed.The titration is then made as usual with the iodine solution to be standardized. The results obtained are in good agreement with those obtained by standardizing a thiosulphate solution with potassium bichromate in the usual way and titrating the iodine against the thiosulphate. The author also recommends the use of potassium hydrogen iodate which reacts with potassium iodide as follows in acid solution : KH(IO,) + lOKI + llHCl = 61 + KC1 + 6H20 and in neutral solution according to the equation : 6KH(I03) + 5KI = 31 + 11KI0 + 3H20, whilst its purity can be easily determined by titration with alkali. A. G. L. Tests and Reactions of Hydrogen Peroxide. C. Schmatolla. (Pharm. Zeit.1905 I. 641; through Pharm. Jour. 1905 lxxv. 910.)-Ten 9.c. of hydrogen peroxide should not require more than 0.25 C.C. of & alkali for neutralization using Congo red as an indicator. The presence of hydrochloric acid is very objectionable in samples intended for medicinal use and hydrogen peroxide containing more than 0.01 per cent. of chlorine should be rejected. To determine this impurity 10 C.O. of the sample are treated with 25 drops of dilute sulphuric acid 0.5 gram of ferrous sulphate and 5 C.C. of TV silver nitrate solution. The silver is then titrated back with The following test will detect hydrogen peroxide in a dilution of 1 1,000,000 : 200 C.C. of the solution to be tested are acidified with a few drops of dilute sulphuric acid and about the same quantity of a 1 per cent.cobalt nitrate solution is added. On then adding potassium hydroxide solution drop by drop a sharp brown colour-t hioc yanat e solution. reaction is produced if hydrogen peroxide be present. w. P. s THE ANALYST. 97 A Substitute for Hydrogen Sulphide. J. Ducommun. (Chem. Zed. Rep., 1905 xxix. 379.)-The acidified solution of the metal or metallic salt is treated with 2 to 5 C.C. of formalin solution and then with a moderately concentrated solu-tion of pure sodium sulphide. If a metal of the arsenic-tin group be present the corresponding sulphide is at once precipitated. On adding alkali to the filtrate the precipitate of the iron group is obtained. The addition of the formalin prevents any separation of sulphur E. K. H. Determination of Oil in Paraffin-Scale. L. Neustadtl. (Chem. Zeit. 1906, xxx. 38.)-In the method proposed advantage is taken of the insolubility of paraffin in acetone at a temperature of - 15" C. whilst the oil present is completely soluble. One gram of the finely-divided paraffin-scale is mixed with 10 C.C. of acetone and allowed to stand for two hours at the ordinary temperature with occasional shaking. The mixture is then cooled to -15" C. and the solid paraffin collected on a small plug of cotton-wDol contained in a filter-tube. The latter is surrounded by a funnel, and the space between the two filled with a freezing mixture. After washing the filter and its contents with acetone cooled to - 15" C. the filtrate and washings are evaporated the residue is dried at 100" C. and weighed The results obtained are, as was to be expected somewhat higher than those yielded by the older methods in which the oil was pressed out. w. P. s

ISSN:0003-2654    

DOI:10.1039/AN9063100081

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

THE ANALYST. 97 REVIEW. SELECT METHODS IN FOOD ANALYSIS. By Drs. LEFFMAN and BEAM. (London: Rebman. Price 11s. net.) Since the publication in 1901 of this very useful handbook considerable additions have been made to our knowledge of food chemistry, and many new processes have been devised. This progress, to which American chemists have contributed a very full share, has necessitated a revision of the work and the insertion of much new matter. Among the more important additicns are descriptions of useful distillation and extraction processes; new methods for the detection of natural colours used as substitutes for fruit colours ; improvements in the detection and estimation of form- aldehyde, boric acid, and other preservatives ; and some new information in connec- tion with the analytical chemistry of butter, oleo-margarine, and other fats.The arrangement of the book leaves nothing to be desired, and although the descriptions of analytical processes are invariably brief, in very few cases has compression been secured at the expense of clearness. The estimation of minute traces of arsenic in food products is a matter with which American chemists are perhaps no$ quite so in- timately acquainted as their English colleagues, and the section devoted to this subject is capable of being improved. On p. 62 the operator is told to use 3 grams of zinc in the Marsh-Berzelius flask, and to allow the action to proceed for one hour after the addition of the material to be98 THE ANALYST. tested, It is not quite clear how a sufficient supply of gas is to be obtained by the employment of so small an amount of metal in a test which, according to the authors’ instructions, is to last for rather more than one and a half hours.Nothing, moreover, is said to warn the analyst against the use of (‘ insensitive ” zinc. On p. 91 the size of the pepper-starch granules is curiously said to vary from 0 to 5.5 microns. Mention is made of the use of cocoanut oil as a direct or indirect butter adulterant, but it is to be regretted that the authors do not give more detailed and definite information as to the methods to be employed for its detection. The illustrations are as a rule good, the plate showing the microscopical appearance of certain of the starches being one of the least satisfactory. To the English eye such words as sirwp and analogs have a strange appearance, but the spelling may perhaps be defended on the ground of simplicity, and at least does no violence to the principles of etymo- logical science, The same cannot, however, be said for the word Zevulose. The work is described in the authors’ preface as being intended “for the practical worker in the detection of food adulteration,” and all such will welcome it as one of the best contributions to this important subject which has yet appeared. A. C. C.

ISSN:0003-2654    

DOI:10.1039/AN9063100097

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

98 THE ANALYST. INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND. ANNUAL MEETING. THE twenty-eighth Annual General Meeting of the Institute of Chemistry of Great Britain and Ireland was held at 30, Bloomsbury Square, on Thursday, March 1, Mr. David Howard, the retiring President, in the chair. The accounts for 1905 having been submitted by the HON. TEEASURER (Mr. A. Gordon Salamon), and duly received, Dr. JOHN A. VOELCKER moved the adoption of the Annual Report. He congratulated the Council on their work during the past year, and he specially alluded to the steps they had taken to protect the interests of professional chemists. Mr. ARTHUR E. EKINS seconded, and the Report was formally received and adopted. Scrutineers having been appointed to count the votes sent in for the election of the officers and members of Council, and ballot having been taken for the election of censors, the meeting proceeded to select the honorary auditors, and Messrs.Robert E. Alison, W. T. Burgess, and P. A. E. Richards were appointed. The PRESIDENT then delivered his address. After referring to the progress made by the Institute during his term of office as President, he dealt more particularly with the history of the third and last year. While the roll of Fellows and Associates has steadily increased, he noted with regret the death of some of the original Fellows, and he mentioned especially John Lloyd Bullock, largely to whose incentive was due the foundation of the Royal College of Chemistry and the invitation to Hofmann to come to London. How much that meant to not a few, including several past Presidents of the Institute, it would take long to tell.THE ANALYST.99 The Institute was examining over one hundred candidates yearly, and arrange- ments would be made from time to time for examinations in the colonies. Mr. HOWARD alluded to the improvement in the financial position of the Institute, and to the steady growth of the library. He paid a high tribute to the services of Professor Adrian J. Brown, who had held the appointment of Examiner to the Institute in Biological Chemistry since 1901, and stated that, as his term of ofhe had expired, the Counoil had selected Dr. Arthur Harden, of the Lister Institute, as his successor. He also referred to the new examinations in technical chemistry, the first of which will be held in October next.In this connection he expressed the hope that the Institute would in future have for its Presidents industrial chemists, as well a8 those eminent for educational and strictly professional work. The chief function of the Institute was to register competent consulting, analytical and technical chemists, and the Institute might safely claim to represent the profession. The Council regarded it as their duty to advance the interests of the profession, and, as far as they were able, to maintain it on a sound and satisfactory basis. They had lately been obliged to make representations to authorities whose actions appeared to be detrimental to the profession. With reference to the gratuitous performance of analyses at agricultural colleges, he mentioned that the Board of Agriculture had endeavoured to show that the performance of cheap milk tests had been arranged for educational purposes.At the same time the Board had stated that these tests were not seriously to be compared with the analyses made by public analysts and district aualysts. The Council had to complain of more than the milk tests : the colleges were undertaking all kinds of analyses at nominal fees-of soils, for instance, at half a crown. This was undoubtedly injurious to the profession ; but the Board, in its journal, stated that ( 6 the demand on the part of landowners for expert advice from the lecturera had been considerably in excess of what might reasonably have been anticipated.” In this matter the Council had not received a satisfactory response.He referred to the great advances in chemistry that had been due to the work of private practitioners, giving his opinion that any action which tends to interfere with the individual practitioners would be fatal to progress. It was with reluctance that the Council had to take up an attitude which might seem in any way antagonistic to the National Physical Laboratory, but they had been obliged to direct the attention of the Executive Committee to the fact that their test pamphlet indicated that they might undertake work which they were forbidden to undertake under the Treasury Report on which the laboratory was founded. The Executive Committee has recently given their assurance of their desire to avoid any cause for complaint.He was sure that the Council would be glad to see the laboratory placed on such a sound footing financially that its authorities would have no temptation to extend the work of the laboratory beyond its proper sphere. Mr. HOWARD thought the profession had reached a somewhat critical stage in its history. With greater facilities for training and, consequently, a larger supply of chemists, it was evident that only the most efficient could hope to be successful.100 THE ANALYST. He believed the demand for chemists was increasing, but authorities and manufac- turers were learning that they must have efficiency. After dealing briefly with the present position of the industrial chemist and the official professional chemist, he referred to the professors and teachers of chemistry.He objected to the practice, which had grown of late, of blaming the Universities for the loss of certain industries. He maintained that, while chemists were improving SO greatly in efficiency, it was absurd to blame the professors. Every decade does not bring a Hofmann, but there were many teachers at the present day under whom the bulk of Fellows and Associates were proud to say they had been trained. The Institute afforded a great benefit to the public by aiding its discrimination in the selection of competent chemists of acknowledged ability and professional integrity ; they could rely on each Fellow and Associate to further the reputation of the Institute by his character and conduct, the soundness of his work, and by the cultivation of professional feeling.Mr. HOWARD then referred to the new President, Professor Percy F. Frankland, who had long been associated with the Institute, and whose father, Sir Edward Frankland, was the founder and first President. He concluded by saying how much he had appreciated his position as President of the Institute, and he spoke in warm terms of the co-operation of the Councils with whom he had worked A vote of thanks for the address was moved by Mr. THOMAS TYRER, seconded by Professor J. MILLAR THOMSON, supported by Mr. R. J. FRISWELL, and carried unanimously. On the report of the scrutineers the result of the balloting for the selection of censors was submitted, and Mr. David Howard ; Sir William Ramsay, K.C.B., F.R.S. ; Thomas Stevenson, M.D. ; and Professor J.Millar Thomson, F.R.S., were declared elected. The officers and members of Council for the ensuing year were then declared elected, as follows : President : Percy Faraday Frankland, LL.D., Ph.D., F.R.S. Vice-Presidents : Edward John Bevan ; Edward Divers, M.D., D.Sc., F.R.S. ; David Howard ; Edmund Albert Letts, D.Sc. ; Edmund James Mills, D.Sc., F.R.S. ; Sir William Ramsay, K.C.B., LL.D., F.R. S. Hon. Treasurer : Alfred Gordon Salamon, A.R.S.M. Members of Council : Adrian John Brown, KSc. ; Lieut.-Colonel Charles Edward Cassal ; Arthur Crozier Claudet, A.R.S.M. ; John Norman Collie, Ph.D., F.R.S. ; James Kear Colwell ; Cecil Howard Cribb, B. SC. ; Henry John Horstman Fenton, M.A., F.R.S. ; Martin Onslow Forster, D.Sc., F.R.S. ; Richard John Friswell ; William Gowland, A.R.S.M. ; Arthur George Green ; Henry George Greenish ; Oscar Guttmann ; James Hendrick, B.Sc. ; Egbert Grant Hooper ; Herbert Jackson ; Arthur Robert Ling ; Henry de Mosenthal ; Henry Droop Richmond ; Alfred Smetham ; Arthur Smithells, B.Sc., F.R.S. ; John Edward Stead, F.R.S. ; David Alexander Sutherland ; Francis Napier Sutton ; Edward William Voelcker, A.R.S.M. ; William Palmer Wynne, D.Sc., F.R.S.; Sydney Young, D.Sc., F.R.S. On the motion of Lieut.-Colonel CHARLES E. CASSAL, seconded by Mr. P. GERALD SANFORD, a vote of thanks was accorded to the retiring officers and members of Council. The PRESIDENT having replied, the meeting terminated.

ISSN:0003-2654    

DOI:10.1039/AN9063100098

出版商:RSC    

年代:1906

数据来源: RSC