ISSN:0003-2654    

DOI:10.1039/AN87803FP013

出版商:RSC    

年代:1878

数据来源: RSC

ISSN:0003-2654    

DOI:10.1039/AN87803BP015

出版商:RSC    

年代:1878

数据来源: RSC

摘要:

ON TWO ANALYSES OF WATER DRAWN FI1036 THE SANE WELL. By A. DUPBE’, Ph.D. F.R.S. Read before the Society of Public Analysts on 1st Hay, 1878. A SHORT time since I received from Mr. R. Field, the well-known sanitary engineer, two aamples of water for examination. Both samples mere drawn from wells situated close to the dwelling house which they supplied, at front and back respectively. Finding one of these waters to be very decidedly the best, I recommended that this only should be used for all culinary and other purposes.In reply to my report I was informed that the water I had recommended could not be used owing t o the bad smell it evolved on boiling. or in the boiler, and that probably some mistake had been made in marking the samples. Accordingly 1 had a second sample of water from the well I had recommended forwarded to me, of which I need here only say that it proved conclusiyely that no mistake had been made the first time.When, however, I took about two pints of this water and raised it nearly to boiling it evolved, more particularly on shaking, a very offensive smell. Testing the smell of the water in my usual way, i e . , by heating about five ounces of it to a temperature of looQ I?., shaking up briskly in a wide mouthed bottle, and at once applying the nose, I still failed to detect any smell. No trace of sulphurctted hydrogen was present.Here then was a water clearly unfit for domestic use, which analysis had never- thelees, as the figures given below will show, pronounced pure. This result puzzled Mr.Field not a little, the more so as he considered the whole surroundings of the well as exceedingly unfavourable. The case was also extremely unsatisfactory to myself, as266 THE ANALYST. in the face of my analysis, confirmed by the second sample, I could not do otherwise than pronounce the water to be pure, barring the offensive smell evolved on boiling. A few days later Mr.Pield, who had meanwhile again visited and carefully inspected the place, an inspection which confirmed all his previous misgivings, informed me t4hat the house to which the well in question belonged had not been inhabited for some months past, and that during such time little or no water had been drawn from the well. I therefore requested to be furnished with a third sample from the same well, which was, however, to be taken only after the well had been as far as possible pumped dry and then been allowed t o refill itself.The analysis of this water, also given below, shows a considerable degree of pollution, and indeed proves the water to be unfit for domestic use, The offensive smell evolved on boiling was however, if anything, rather less marked in this than in the previous sample.How then is this striking difference in the character of the water drawn from the same well t o be accounted for? It is, of course, well known that even very foul water left to itself, in tanks or barrels, becomes purified and fit for drinking in process of time, and I suppose that something similar had taken place in this case, The water, left undisturbed in the well for months, had undergone a gradual process of purification, aided perhaps by vegetation or by dilution with rain-water.Similar cases have, I believe, been observed by others, but I venture nevertheless to bring it before you as it emphasises far more strongly than any case I am acquainted with the absolute necessity of having a considerable quantity of water drawn from a well before the sample is taken for analysis. Had the water in the present case not possessed thi8, 80 to speak, accidental and minor character of smell, the well would have been considered good in spite of its surroundings and the misgivings of the engineer, and serious mischief might have resulted.I n conclusion, I may state that the well in question has a depth of seventeen feet with about eight feet of water.The upper part, down to within about half a foot of the water level, passes through vegetable mould, sand and gravel, the remainder is in the chalk. The chalk in the neighbourhood of the well is penetrated by innumerable rootlets, and when broken up gives out a very offensive smell. Round these rootlets, many of which are decaying, the chalk is colwred black by sulphide of iron.A cesspool, now about t o be filled in, is situated at a distance of about seven yards from the well, and a brick drain runs at about the same distance past the well, which latter I need scarcely add will also be filled up. Appearance . . . . . . . . . clear . . . . . . Colour . . . . . . . . . . . . pale greenish . . . . . . Taste .. . . . . . . . . . . tasteless .., * a , Smell . . . . . . . . . . . . inodorous" .I. .** Deposit . . . . . . . . . . . . none . . . . . . Nitrous Acid . . . . . . . . . none . . . . . . Phosphoric Acid . . . . . . very strong trace . . . . . . Hardness before boiling, ... 27'0 degrees (Clark) . . . . . . .. after . . . . . . . . 9.5 ,, ,? . . . . . . Oxygen absorbed from permanganate 0*014 . . . . . . 0.035 Total dry residue . . . . . . 37.80 . . . . . . Coneisting of volatile matter 1-40 . . . . . . Chlorine ... . . . . . . 2-24 ...... 3.29 Nitric Acid (Np. Ob.) . . . . . . 0'11 . . . . . . 2-66 Ammonia . . . . . . . . . o*ooo . . . . . . 0.013 Alhiirninoid Ammonia . . . . . . 0'004 . . . . . . 0.010 The well was closed in by a brick vault. First Sample. Last Sample. Grains per gallon, {fixed salts ... 36*40} ...... ,i This refers t o the usual-mode uf testing if,

ISSN:0003-2654    

DOI:10.1039/AN878030265b

出版商:RSC    

年代:1878

数据来源: RSC

摘要:

THE ANALYST. 267 ON THE COMPOSITION OF HONEY. Read 6efore the Xociety of Padlic Anakysts OP 1 s t May, 1878. TBEBE are so few analyses of honey on record that it seems desirable to bring before this Society a selection of analyses of authentic examples of genuine honey with which commercial samples may be compared. The only detailed analyses of honey with which 1 am acquainted are those published in Hassall’s But as they do not give the proportions of the different kinds of glucose, but only the total glucose, and are accompanied by the extraordinary statement (p.274) that starch sugar is the adulteration, which it is scarcely possible in many cases to detect, they will not be of much practical value to the members of this Society. The analytical determinations which are useful in the analysis of honey are the following :- BY J.CAMPBELL BROWN, D.SC. Food and its Adulterations,” 1876, p. 266. 1. 2. 3. 4. 5. 6. 7. 8. 9. Estimation of the water of solution expelled at a temperature slightly over looo c. Water of combination and other volatile matter expelled only at a higher temperature ; this may be sometimes safely estimated by difference.Insoluble matter ; pollen, wax, &c. Xicroscopical examination of the honey, and especially of the pollen. Estimation of the ash, if necessary. Qualitative examination of the ash when the quantity is great. Estimation by the polariscope saccharimeter of the action of a solution of known The same after inversion. Estimation of the total glucose by standard solution of copper salt.strength on the polarised ray. 10. A similar estimation after inversion is often useful as a check. The result of 7, 8, and 9 give, by an obvious calculation, the proportions of dextro- and laevo-glucose. The proportion of cane sugar is calculated from 9 and 10, or may be deduced by means of Clerget’s tables from 7 and 8. I have never been able t o satisfy myself of the occurrence of cane sugar in honey ; and I am by no means sure that the figures representing cane sugar in the following analyses, and in those of Dr.Hassall, do not really represent experimental error; my figures for cane sugar are calculated from observed results in which a very small observational error would give a difference of 1 or 2 per cent. RESULTS OF ANALYSES OF AUTHENTIC SPECIMENS OF GENUINE HONEY.English. Welsh. mz:&a German. Greek. Lisbon. Jamaica. fz:l. Mexicall. Water expelled at looo ...... 19.1 16.4 15.5 19.11 19.8 18.8 19-46 17.9 18.47 Water expelled at a much higher temperatureand loss] 7-6 6.56 4.95 11’ 7-8 6.66 7.58 8.13 10.03 Laevulose ........................ 36.6 37.2 36.88 33.14 40. 37.26 33.19 37.85 35-96 Dextrose .......................36.65 39.7 42.5 36.68 32.2 34.94 35-21 36.01 35.47 Cane sugar (?) .................. } d~::t-none. none. none. none. 2.2 none. ‘;$t- *05 ne$,, 2.1 f;:, trace. Wax, pollen, and insoluble) good trace, slight trace, Mineral matter .................. .15 ‘14 *17 *17 -15 -14 *26 *11 907 1.2 matter ........................ j trace. trace.268 THE ANALYST. The specific gravity of honey is about 1-41, but varies slightly with the proportion of water.The proportions of water are higher than might have been expected, but I have confirmed some of the above results by a combustion with oxide of copper. The rotation of a polarised ray, produced by a solution of 16-26 grammes crude honey in 100 C.C. water, is generally from - 3 O - 2 to -FjQ at 60° Fahr. The only one of the above samples which gare a higher rotation was the Greek honey, which gave nearly -54O. The rotation produced by a solution of the same weight of dried honey is generally not far from --4O-8 ; but some latitude must be allowed until a larger number of observations have been made.

ISSN:0003-2654    

DOI:10.1039/AN8780300267

出版商:RSC    

年代:1878

数据来源: RSC

摘要:

268 THE ANALYST. EXPERIMENTS ON TEE DETERMINATION O F THE FREE ACIDS OF VINEGAR. BY ALFRED H. ALLEN AND R. BODMER. Read before the Society of Public Analysts, on the 20th Harch, 1878. WITH the view of ascertaining the extent to which the known methods of determining the acids of vinegar could be trusted, we have instituted a series of experiments on repre- sentative mixtures of known amounts of the constituents of vinegar.As a starting point, we prepared a pure acetic acid by distilling the commercial acid after addition of a little soda. The distillate had a density of 1.0396 at 15” C. According to Oudemann, this number corresponds t o 28.67 per cent. of real acetic acid (C, H, 0,), or, according to Mohr, to 29.5 per c a t . The figures of the latter chemist’s table of densities are only carried to three placerr of decimals.Weighed (not measured) quantities of the above sample of acid were next titrated with decinormal caustic soda, using litmus as an indicator. The results shewed 28-54, 28.44, 28.49, and 28.59 per cent. of real acid, the average being 28.515. Another titration, in which a few drops of cupric sulphate were employed instead of litmus (a permanent turbidity being taken as the end of the reaction), gave 23-52 per cent.of acetic acid.” It will be seen, therefore, that the two methods of titration gave extremely close results, and that the amount of acid calculated from the density (by Oudemann’s table) was slightly higher than that found by titration. This result is in accordance with the general opinion that titration of acetic acid gives results slightly below the truth.A dilute acid was next made by mixing a quantity of the above sample with nine times its weight of water. A portion of it was then titrated, (using litmus), when it gave 2.853 per cent. of acid,-almost exactly one-tenth of the original amount. On the other hand the density was 1.0040, which corrcsponds t o 3.20 per cent.of acid according to Oudemann, or 3.0 according to Mohr. Hence, the two parts of Oudemann’s density tables are inconsistent. The fact that the part of the table referring to 28 per cent. acid gives results agreeing fairly with the titration method, while that referring to 3 per cent. gives discordant results, shews pretty clearly the direction of the error. It is, of course, impossible to ascertain the cause of the discrepancy with certainty, but it is worth * Another sample of acid gave 27.27 aa the mean of three titrations in which the end of the reaction was indicated by litmus, and 27-25 as the mean of three in which Cu SO4 was employed.Hence, if there be an error of deficiency introduced by the w e of litmus, the 8ame objection applies to sulphate of copper, and probably other indicators.THE ANALYST.269 notice that if one measure of acid at 29 per cent. were diluted with nine measures of water, the dilute acid would really contain 3.004 per cent., instead of 2-9 per cent. as might often be assumed. These considerations have no relation to, and are in no way affected by, the well- known abnormal density of strong acetic acid.On the whole, we considered that the real amount of acetic acid in the sample was represented most accurately by the result of the titrations, and therefore in the following experiments the acid used is regarded as containing 28-52 per cent. of real acetic acid (Q H, 0,). I n all cases in which acetic acid was to be determined, a weighed (not a measured) quantity of the sample was employed.A. The first process tried was the determination of free acetic acid in presence of free sulphuric acid, by adding excess of' carbonate of barium, boiling well, filtering, and precipitating the barium from the filtrate by dilute sulphuric acid. The amount of Ba SO4 found represents an equivalent amount of acetate of barium formed, and the weight multiplied by *515 gives the acetic acid.HX Taken. Ea' Found, Expt. 1. ,447 grms. . . . . . . . . . . . . . . . . . . *456 grm. Expt. 2. 9397 ,, . . . . . . . . . . . . . . . . . . '406 ,, These experiments shewed, as was to be expected, that free acetic could be readily determined in presence of sulphuric acid. Unfortunately the method is useless in presence of sulphates and many other salts.B. In this case, the above method was modified so a8 to render it applicable to the analysis of acetates, and to free acetic acid in presence of sulphates. A known weight of the sample of acid was neutralized with standard soda, and standard sulphuric acid added in twice the quantity necessary for the conversion of the soda into NaHSO,. The liquid was then distilled nearly to dryness, water added, and the distillation repeated.The distillate was treated with Ba CO,, as in process A. Expt. 3. *548 grms. . . . . . . . . . . . . . . . . . . $61 grms. Expt. 4. 1,126 ,, . . . . . . . . . . . . . . . . . . 1.118 ,, H r Taken. HX Found. If sulphate of silver were added before distillation, the method would be equally accurate in presence of hydrochloric acid and chlorides.Phospharic acid has some- times been employed instead of sulphuric acid, and would, doubtless, be preferable in presence of sugar, &c. C. The next process investigated was that for the determination of free sul- phuric acid in vinegar, by precipitating the sulphates with alcohol. An artificial vinegar was made by adding to dilute acetic acid some caramel, calcium sulphate, potassium sulphate, and a known quantity of standard sulphuric acid, in such quantity that the liquid contained about 6 per ceut.of Ha, and 1 per cent. of H,SO,. 50 C.C. of the (' vinegar" were evaporated to 10 c.c., and treated with 50 C.C. of rectified washed with alcohol, and H,SO, precipitated with results : - &SO4 Added. Expt, 5. -636 grms. Expt. 6.-536 ,, spirit. After standing, the precipitate was filtered off, the filtrate diluted, the alcohol boiled off, and the free barium chloride. By this process we obtained these HzS04 Found. . . . . . . . . . . . . . . . . . . ,655 prms. . . . . . . . . . . . . . . . . . . e53a ,,270 THE ANALYST. Hence, it appears that, provided sufficient alcohol be added, a very exact separation of free from combined sulphuric acid, can be effected.A sample of commercial vinegar treated by the above method, shewed no free sulphuric acid, whilst it contained sulphates corresponding to no less than -159 per cent. (= 111 grp. per gallon) of H2S04. The same vinegar contained 63 grs. per gallon of chlorine. These results, given by vinegar of unknown origin, present a curious resemblance to those obtained by Lethcby from the article manufactured by Messrs.Hill and Evans, of Worcester. No KHSO, is formed. These were :- H2SO4 (as sulphates.) GI. Two experiments were next tried by adding to 50 C.C. of the above sample of commercial vinegar a known amount of standard sulphuric acid, and proceeding as before. I n the Vinegar. ... 11 1 grs. per gallon ....... 50 grs. per gallon. In the Water. ... 119 ,, ,, ... ... 48 ,, 9 7 Expt. 7. For 0.268 grm., H2S04 added, *188 was obtained. Expt. 8. ,, 0.268 ,, 9 , -190 ,, Hence, a considerable and nearly equal loss occurred in both cases, the mean being -079 grms. Of this, -062 is accounted for by the reaction of the sulphuric acid added, upon the chlorides present in the vinegar. The remaining *017 grms.pro- bably reacted on acetates or phosphates. The conclusion to be drawn from the experiments is that the alcohol method will shew the true amount of sulphuric acid existing free in the vinegar, but that will probably be less than the amount added. By adding sulphate of silver before concentrating, the result would indicate the total free mineral acid in terms of sulphuric acid.The process thus modified would be applicable to the determination of free hydrochloric acid. This ie based on the fact that, while acetates are conv'erted into carbonates on ignition, and hence yield an alkaline ash, sulphates and chlorides suffer no similar change. Mr. Hehner further proceeds on the assumption that the presence of acetates in the vinegar is incompatible with that of free hydrochloric or sulphuric acid in the original vinegar, and hence any alkaline reaction of the ash of the vinegar, by proving the presence of an acetate, negatires the possiblity of the presence of a free mineral acid.It was to be expected that the evaporation to dryness and subsequent ignition of a solution containing acetic acid, free sulphuric acid, and a sulphate, would D.We next examined the very convenient process of Mr. 0. Hehner." produce a non-alkaline ash, but the same result seemed by no means certain if a chloride were evaporated with a comparatively large quantity of acetic acid. In this case it was thought probable that the effect of mass would be observed, and that the large proportion of acetic acid would effect more or less decomposition of the chloride, with volatilization of hydrochloric acid and formation of an acetate.To obtain information on this point we made the following experiments :-A solution of common salt, in which the chlorine had been determined by nitrate of silver, was evaporated with a large excess of acetic acid. In some cases the operation was concluded at dryness, in others the solid residue was ignited.In some cases burnt sugar was added. The chlorine in the residue was determined by nitrate of silver. * see ANALYST vol. 1, p. 135.THE ANALYST. 271 Expt. 9. ‘0504 grms. of Na GI, evaporated to dryness with a large excess of acetic acid, gave a Expt. 10. The same experiment repeated, gave absolutely the same amount of Na C1 before and Expt. 11.The same operation, with subsequent careful ignition of the residue, showed a loss of Expt. 12. The same operation as in the last experiment, but with caramel added, shewed a lose Expt. 13. Conditions the same. Loss = 00014 grms. Na C1. It appears from these experiments that the decomposition of the salt is practically nil, by mere evaporation, but that on ignition there is a loss of 2 to 3 per cent.of the total chlorine present. As there can be no free acetic acid present to account for this loss, it is probably due to unavoidable volatilization of the chloride, rather than to its decomposition. On the other hand, when chloride of sodium solution was evaporated with tartaric acid, and the residue ignited, 36 out of 54 milligrsmmes of salt were decomposed, or Q of the total quantity taken.We also evaporated common salt solution with excess of cream- of-tartar. This result was to be expected, as even acid szt&hate of potassium does not react on common salt at moderate temperatures. On igniting the evaporated mixture of sodium chloride and cream of tartar, slight decomposition occurred, in one experimeiit 3 milligrammes, and in another 4 milligrammea of common salt being decomposed, out of the 50 milligrammes added.When a solution containing 50 milligrammes of sodium chloride was evaporated to dryness (but not ignited) with excess of citric acid, the residue gave a weight of AgCl corresponding to only -036’7 grms. of Na C1, shewing a loss of 24.6 per cent. of the common sslt taken. These experiments have a bearing on the method of Mr.W. C. Young for the determination of mineral acids in vinegar.* His process consists in adding excess of Ba CI, t o a known measure of the vinegar. I n a portion of this liquid the chlorine is determined. The rest is evaporated, ignited, and the chlorine determined in the ash. The difference represents the free mineral acid expressed in terms of C1.Acid tartrate of potassium is, of course, a constituent of wine-vinegar, and its presence would cause the determination of mineral acid by the above method to be somewhat too low. residue containing -0496 grms. of Na GI. Loss *0006 grms. after evaporation with acetic acid. *0012 grms. Na C1. of -0014 grms. Na GI. By mere evaporation to dryness no decomposition of the chloride ensued.The presence of free tartaric acid would quite invalidate the results. As citric acid decomposes a chloride on evaporation of a solution containing it, it is clear that Mr. Young is in error in stating that his process is of course applicable to lime- juice or lemon-juice.” Mr. Eehner’s method of determining free mineral acids in vinegar, is dependent on the alkalinity of the ash of the vinegar as compared with the amount of alkali added to the original liquid.‘( I f we add to a measured quantity of the vinegar a known and exactly measured volume of decinormal soda solution, somewhat more than would be necessary to neutralise the total amount of free mineral acid present, evaporate and incinerate, the alkalinity of the ash gives the measure of the quantity of the free aulphuric or hydrochloric acid.” The author’s test experiments are very satisfactory.See ANALYST vol. 3, p. 163,272 THE ANALYST. It is evident that the amount of alkali added must be sufficient to combine with the fixed organic acids present, in addition t o the mineral acids. I f the amount of alkali employed be insufficient, it is necessary to recommence the experiment.For this reason, and from the desire to determine the free acetic and the mineral acid in the same portion of vinegar, we have made some experiments in which enough normal soda was employed to neutralize the whole of the acid, the subsequent manipulation being unchanged. As the amount of alkali used was about 20 times as great as that employed by Mr. Hehner, the tendency t o a slight error in the titration was greatly increased, but the following results show that this modification of the process is capable of all desirable accuracy.An artificial vinegar was made by mixing acetic acid, potassium sulphate, caramel, and a known amount of standard sulphuric acid. A slight excess of standard soda was added, the liquid evaporated, the residue ignited, the ash dissolved in excess of standard acid, and titrated back with alkali.Expt. 18. For -2735 H2S04 taken, . . . . . . . . . -2695 was found. Expt. 19. ,, -2735 ,, ,, . . . . . . . . . -2755 ,, The commercial vinegar already mentioned as containing sulphates equivalent to 11 1 grains per gallon of sulphuric acid, in addition to 63 grains of chlorine, when examined by this process, Ehowed a small minzcs quantity of free sulphuric acids-a result fully oonfirming the alcohol determination.Another experiment was made by adding a definite amount of standard sulphuric acid to 50 c. c. of the above commercial vinegar, and then proceeding a5 before, when we obtained :- H2S04 Taken. H2SOa Found. Expt. 21. . . . . . . . . . -1220 grms. . .. . . . . . -1157 grms. As, however, a small error in the amount of alkali and acid used causes a sensible difference in the result, it is preferable to add (as recommended by Mr. Hehner) only a fraction of the total alkali which would be required for complete neutralization. Under these circum- stances, decinormal solutions can be conveniently employed, and hence greater accuracy in the results obtained. It will be observed that in Expt.21 nearly the full amount of sulphuric acid added is accounted for. Of course the result is really a determination of the free mineral acids (actually existing in the Tinegar) expressed in terms of sulphuric acid, for theoretical considerations and the results of experiments 7 and 8 (made on the same vinegar by the alcohol process) show that a considerable proportion of the free acid was hydrochloric acid. In short, Hehner’s process determines the total amount of free mineral acid, while the alcohol process,-with the use of sulphate of eilver if necessary-enables the relative proportions of the free mineral acids to be ascertained. Hehner’s procesa is in our experience, decidedly the most convenient and accurate in general use, and furnishes a valuable solution of a somewhat difEcdlt problem. R. Warington has employed the Bame plan for the determination of free sulphuric acid in citric acid liquors, and the same principle has been frequently made use of. Hence the process gives fairly accurate results in actual practice. * A minus result is very common with vinegars containing no free mineral acid, and, when beyond the limita of experimental error, is clearly due to the presence of acetate8 or other organic adts (e.9, malatee, lactates, tartrates.)

ISSN:0003-2654    

DOI:10.1039/AN8780300268

出版商:RSC    

年代:1878

数据来源: RSC

摘要:

THE ANALYST. 273 REVIEW. MICROSCOPIC MOUNTING.” AFTER a careful perusal of Mr. Martin’s manual of microscopic mounting we find therein points for both praise and disapprobation. As it is always most pleasant to be able to approve of any portion of a work, we do the praising first. It is an excellent gathering together of useful mounting formuh, and gives a good description of manipulation, but there the praise must end, as the matter imported into the work on adulteration, &c., and the drawings illustrative thereof, do not partake of the useful nature of the portion already alluded to.Had the book been published simply as a collection of well-established formuh for mounting liquids, with the directions for use, it would have been a most convenient work, but the l C padding” in which the autho seems to sometimes get out of his depth, spoils the book in its present form.On page 2, et seq., we are git-en a list of apparatus required, and are told that “the student must also add, buy, or make, 8s convenient to him, the following articles”: Then follows a list, extending over two pages, of no less than 95 distinct articles (including chemicals), commencing with “ an air pump,” and ending with “ pill-boxee, small pins, cardboard, &c., &c.,” although what on earth the &c., &c., can stand for, we are at a loss to conceive, seeing that we find such sundries as “old knives” and ‘ l Liebig’s extract of Eeat jars” already enumerated.We fear that if an ordinary knowledge of the microscope could not be got without procuring all this formidable list of articles, students would be much alarmed at the prospect. Again, on page 51, we have a drawing which is supposed to represent the method of making a bottle in which insects can be killed by the exhalation from laurel leaves, but the artist cannot have carried out the author’s intention, as the quantity of leaves are so, ridiculously minute that tbey would be quite inoperative.On page 27 we have an illustration of a retort with a flask-receiver, in a basin, presented as a specimen of ‘‘ apparatus for making gaaes, distillation, &c.,” but as there is no appliance for keeping the receiver cool, the latter process would be somewhat difficult. On page 161, we find that some granules, (‘ by their globular character, are known t o be wheat starch.” Now, any microscopist knows that the special feature of the wheat granule is its flatness and want of globularity.Again, on page 175, when the author drops into chemistry, me find that the method of examining cayenne for the presence of vermilion and red lead, is to ignite it to ash on Let us justify these remarks by shortly glancing at a few matters.platinum foil, and test what remains on thought that vermilion was volatile by organic matter, suffered reduction when the foil, but perhaps it is the residue on the author meant to indicate. the foil for the metals. Now, we have always heat, and that an oxide of lead, mixed with heated, and then generally went right through the ceiling of the room, or on the table, that It is, however, when we come to the drawings of food adulteration that the worst point of the book appears, becauae they are really 80 out of proportion that comparison is simply impossible.In plate 10 we have pepper, with the particles representing the starch drawn as an almost imperceptible powder, while in plate 11 rice starch is figured with a diameter of nearly a quarter of.an inch in some * A Manual of Microscopic Mounting, by J. H. Martin. London : Churchill & Co.274 THE ANALYST. granules, the former being stated to be magnified 50, and the latter 450 diameters. Now, rice starch being simply twice the size of pepper, it follows that the relation of the drawings should be as 1 to 10, whereas here they are as 1 to 50 nearly. When we say that, as t o the rest of the drawings, they are made under such a low magnification as to be practically useless, even with the author’s direction to examine them by a lens, and that wheat starch is shown in plate 11 covered with highly-marked perfect rings, while in plate 10 it appear8 exactly like oil drops, we have said enough.I n conclusion, me say, let Mr. Martin, in his next edition, cut out all his ‘( adulteration ” and ‘‘ chemistry,” and pnblish simply his really good collection of recipes and directions for mounting, and all mill be well. We should also, in the interests of professional dignity, advise him to cut out the advertisement page in which he announces that “ h e has a great and varied experience, both in microscopy and. chemistry, and can be consulted, &c.” However great and varied Mr. Martin’s experience may be, he should not be the one to announce it in this way.

ISSN:0003-2654    

DOI:10.1039/AN8780300273

出版商:RSC    

年代:1878

数据来源: RSC

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274 THE ANALYST. N O T E O N A L U M I N B R E A D . By A. WYNTER BLYTH, M.R.C.S. Read before the Xociety of Pu61ic Analysts, 20th March, 1078. I HAVE found a small percentage of alum in the crust of certain bread, and only the usual minute quantity in the crumb. I understand from the trade that bakers use a strongly alumed flour technically called ‘‘ cones.” This flour is not made into bread, but is used as it mere tofGce the loaves. The hint may be valuable t o my brother analysts, as i t points to the advisability of making a separate analysis of the crumb and crust, I have not seen any mention of this in works I have access to.

ISSN:0003-2654    

DOI:10.1039/AN878030274b

出版商:RSC    

年代:1878

数据来源: RSC

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THE ANALYST. 275 CORRESPO NDE AT CE. [The Editors are not responsible for the opinions of their Correspondents.1 T H E S E L B Y F L O U R C A S E . To THE EDITOR OF ‘‘ THE ANALYST.” Sxa,--In March last I condemned a sample of flour for containing “ about half the usual quantity of alum.” Before the case was heard at Selby, the defendant induced the magistrates to order a portion of the remaining part of the sample to be sent to Somerset House.The result was that the gentlemen occupying the position of chemists at Somerset .House sent a certificate stating that they found the sample to contain an amount of alumina equivalent to 21 grains of ammonia-alum per 41b. of the flour, that their experiments on pure flour had shewn an amount of alumina natural to flour varying from an equivalent of 2 to 10 grains of alum, and that, with regard to the excess of alumina found, ‘‘ the results of their experi- ments did not enable them to affirm the existence of alum.” This certificate is interesting to chemists, as throwing light on the views of the Inland Revenue Chemists on a subject on which they had hitherto been silent.I n the sequel some further information was elicited.Mr. Bell received a subpcena to attend and explain himself, but sent his colleague, Mr. Bannister, instead. Mr6 Bannister explained that the alumina had been determined by DuprC’s method. The opinion that the excessive portion of alumina was not due to alum was based on an experiment made in some way with logwooG, Mr. Bannister shewing a residue dried up at the bottom of a porcelain dish276 THE ANALYST.in confirmation of his statement. I t also appeared that some of the Somerset House Chemists had made a series of experiments with pure flours with and without the addition of alum. On the other hand, I had found an amount of alumina corresponding to 19g grains of alum per 4lb., a result with which the determination at Somerset House agreed well.But there was this difference. As stated in evidence. I had dissolved the ash in HCl, and filtered, before evaporation to dryness to separate silica. By proceeding thus, and omitting the fusion with alkaline carbonate, I believe I leave any silicate of alumina insoluble. I have repeatedly analysed flours and wheat by this method, and have never obtained more alumina in solution than corresponds to 3 grains of alum per 41bs., although on fusing the insoluble matter with alkaline carbonate more alumina may be extracted.This view I expressed at a meeting of the Society of Public Analysts, an account of which appears on page 8, of vol. i., of the Prcceedings but my observa- tions are reported as if I were at the moment referring to Dr.Duprk’s process, whereas, in quoting these figures, I was referring to a process which I have had in frequent use before and since, and in which the fusion is omitted, I fully believe that Dr. Duprb’s method is the best for the estimation of the totalalumina, but by using acid alone, followed by filtration, I think it is possible to discriminate between added and natural alumina, or between soluble and insoluble, Such a plan has the disadvantage that incomplete solution of the alumina of the alum may cause an error of deficiency.In addition to the estimation of alumina 1 had observed the absence of excess of iron, and had determined the ash. I had also had a portion of the flour made into bread, and tested by the logwood and ammonia test. I t was a weak point that I had not been present when the bread was made, but the servant who made it was present ready in Court to swear that she used yeast and water only.(The water is a pure moorland water, containing 5 or 6 grains per gallon of solid matter.) The result of my logwood test on the bread was the production of a distinct, but not very well developed, blue colour. That the Somerset House Chemists failed on the flour, I couttnd, is due to one of two things-either faulty manipulation and inex- perience, or the occasional tendency of the test to fail when applied to flour.I t has certainly failed in my hands, and Hassall condemns it on the same account. Hence, as the Somerset House Chemists faii to obtain the logwood reaction, and ignore the teachings of the alumina, any sample of bread or flour, how- ever much alum it contains, is liable to get reported pure if referred to Somerset House.AB to the amount of alumina natural to wheat, Dr. Dupr6, L)r. Muter, Dr. Stevenson, Mr. Wanklpn, Mr. Wigner, and others agree in finding a maximum even less than that of Somerset House, thougb, pro- bably owing to differences of process, they found more than I have done.d Mr. Reynolds, a druggist, of Leeds, asserts that he found a considerable proportion of alumina in Egyptian wheat some fifteen yeara since, Without wasting time by criticking this statement, I may say that another recent case, in which a high amount of alumina was found, is undoubtedly to be explained by the process employed, Thus, if the calcium and magnesium phosphates are at once precipitated by soda, and the phosphate of aluminium merely recovered from the filtrate, the weight of the latter will be seriously in excess of the truth.If the analysis be conducted in that way the phosphate of aluminium ought always to be redissolved, and precipitated from a cold solution containing free acetic acid. The result of the Selby flour case was that the magistrates dismissed the summons but allowed no cosb.I may add that the same defendants were summoned for another sale of flour, in which I certified to 10 grains of alum per 4lbs., described this amount ia my certificate as insignificant, and wrote a letter to the authorities stating that they must not prosecute, for though my own opinion was decided as to the presence of alum, the proportion was too small for a conviction.I presumed this recommendation had been acted on, until I was informed that the sample had been sent to Somerset House. I write this letter chiefly with the view of raising a discussion on the detection of alum in flour and bread, especially with reference to the logwood test. I am, &c., ALFRED H. ALLEN. SHEFFIELD, May, 1878.T H E B R O M S G R O V E M I L K C A S E . To THE EDITOR OF THE ANALYST.” SIR,--T did not use porcelain dishes for (‘ economy ’’ as my report shows. I used platinum for total solids and ash, but porcelain for the determination of fat. The reason why I considered the use of platinum as an injury to the dealer was that the residue in platinum soon became very hard and dry, and I found I could obtain a larger percentage of fat by the more slow evaporation in porcelain dishes. The whole matter has been a great grief to me, but I have the satisfaction of knowing that the pub- licity given to the case (which cannot but be of injury to myself) has completely exonerated the milkseller from blame.THE ANALYST. 277 My laboratory is detached from my house and under lock and key, and no one is permitted to be there except in my presence.My friend, who unfortunately made the mistake in the tare of the dish had assisted me some time before in an extensive series of milk analyses, and I thought him quite competent in the use of the balance. I made two analyses which agreed with each other of the milk before I made my report, but unfortunately used the same tared dish. Yours faith fu I1 y, HORACE SWETE, M.D., May 23rd, 1878. Analyst, Worcestershire.

ISSN:0003-2654    

DOI:10.1039/AN878030275b

出版商:RSC    

年代:1878

数据来源: RSC

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THE ANALYST. 277 H O U S E O F C O M M O O S . May 23rd, 1878. SALE OF FOOD AND DRUGS ACT IN SCOTLAND. Mr. W. EOLMS asked the Lord Advocate if he was aware that by a recent decision of the High Court of Justiciary the Sale of Food and Drugs Act, 1875, had practically become inoperative in Scotland; and, if so, what steps he proposed to take to remedy that state of things. The LORD ADVOCATE said his attention had been called to the decision in ques- tion.The result of that decision was rather too strongly put in the question. It only affected the sixth clause of the Act, but he admitted that it would have the practical effect of stopping those prosecutions, The Act, however, was one which applied to England as well as to Scotland, and the same point which had been decided by the High Court of Justiciary had been raieed by an appeal from a decision of the magistrates of Sheffield.He understood that that appeal was now pending before the Courts in this country, and he thought it would be better before taking action in the matter to wait and see what the judgment in that case might be.-Times. May 27th) 1878. SELLING SPIRITS UNDER PROOF. Mr.SCLATER-BOOTH, in answer to Sir F. Perkins, who asked whether theatten- tion of the Government had been directed to prosecutions which had been instituted against licensed victuallers for vending spirits of different degrees of strength under proof and the conflicting decisions of local justices on the point, said : The attention of the Government has, from time t o time, been directed to the prosecutions which have been instituted against licensed victuallers for selling Rpirits of different degrees of strength under proof.The policy of the Sale of Food and Drugs Act was to leave it t o the local tribunals to give decisions in accordance with the evidence in each case, and, in order to provide against the inconvenience which might result from varying views among the locally-appointed analysts, it was provided that the opinion of the Commissioners of In- land Revenue might be taken in disputed cases.I have no reason t o doubt that in course of time, by this means, and by the decisions of the High Court of Justice on typical cases brought before them on appeal, greater uniformity of procedure will be arrived at. Mean- while I may say that the statements and facts submitted to me tend to show that there is a natural process of deterioration in the strength of spirits by lapse of time, which should caution local authorities against the institution of proceedings in doubtful cases, and that there is a margin between the degree of about 17 per cent.under proof, which may be taken to be the figure at which spirits are delivered over to the licensed victuallers, and the point or points at which the Superior Courts have supported convictions within which at present some uncertainty must be admitted to exist. There are difficulties in the way of fixing a specific standard, and Parliament has not thought it proper to insert any such in the Act ; but means are provided by which, in doubtful cases, retailers of these articles can protect themselves from prosecution, either by retailing under warranty or by labelling the article sold as of a particular degree of strength below proof.-nmes.

ISSN:0003-2654    

DOI:10.1039/AN8780300277

出版商:RSC    

年代:1878

数据来源: RSC

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278 THE ANALYST. LAW REPORTS. HAMMERSMITH.-ADULTER~TED BUTTER.-John Walker, a wholesale dealer, of the Goldhawk Road, Shepherd’s Bush, was summoned for eelling adulterated butter. Mr. Webb appeared for the defendant, who did not attend. Mr. Jones, clerk of the Fulham Board of Works, attended in support of the summons, and produced the certificate of the analyst, stating that the sample was composed of 75 parts of foreign fat.The inspector, who bought the butter, said he saw a tablet hanging in the shop stating in effect, that all butter sold there was pure. Mr. Webb produced a tablet which stated that all butter sold in the shop was not pure. The inspector said that was not the tablet he saw. Reference was then made to the wrapper of the butter, Mr. Webb stating that i t bore a stamp notifying that the butter was a compound.The paper was inspected, but it was found not to bear a stamp. Mr. Webb said the defendant used a stamp of that kind. Mr. Bridge said it was a bad case, as the defendant was a wholesale dealer. He fined th9 defendant $15 and 12s. 6d. costs. WUDSWORTE.-SHAM BuTTER.-Edward Gould, of Clapham Park Road, was summoned for selling to Samuel Hallen Smith, the inspector appointed by the Board of Worke for the Wandsworth District under the Adulteration of Food Act, butter which was not of the nature and quality demanded.I t was shown by the certificate of Dr. Muter, that the so-called butter was animal fat manipulated so as to resemble butter. George Nicholls, of Clapham Park Road, was summoned for a similar offence.The defendant, who said the stuff was not sold as butter, was fined €10 and 12s. Gd. costs, which he immediately paid. GREENUWX.-ADULTERATED BUTTER-Henry Alexander Thompson, of 4 5 7 ~ , New Cross Road, Deptford, was summoned by the Greenwich District Board of Works, for selling an article of food, butter, which was found to be adulterated. Evidence was given, showing that Mr.Maslen, inspector of the Deptford district, pnrchased a half pound of butter marked at 1s. 4d. per pound, On paying for it he asked the manager, who served him, to divide the butler into three parts, as it was bought for analysis. A certificate was now produced, received from Mr. Wiper, which set forth that the article analysed contained more than 90 per cent. of foreign fat, and rather less than 10 per cent.of butter, which was not necessarily injurious to public health. The defendant’s manager said he believed that on being asked to describe the butter sold he said it was not butter but “butterine.” The inspector said that no such intimation was given, and the entry he had made in a book at the time showed that he (the manager) was reserved, and did not say anything.f i e added that subsequent to tbe analysis being made, in passing defendant’s shop he told the manager the analysis was against the article, and “butterine” was then mentioned. Mr. Slade said the defendant had rendered himself liable to a penalty of $20. There mould be a fine of 40s. and 2s. cost of summons. MANCEESTER-LARD APPEAL CAsE.-An important case under the provisions of this Act was decided on Saturday last by the Lord Chief Baron and Baron Pollock.It was an appeal from the decision of the Manchester bench of magistrates, who declined to convict the respondent under the above Act for selling one pound of lard, which was found on analysis to contain 15 per cent. of water. The contention before the magistrate was that Hopley had sold Rook the lard in the same condition as he himself had bought it, and that under the 25th section of’ the Act he was entitled to an acquittal.The magistrates refusing to fix a fine, their decision was appealed against, hence the present trial. Both judges concurred in the following statement made by Barou Pollock. ‘( Is the thing sold prejudicial to the purchaser, and not of the nature demanded? I think both, though I do not mean that it is calculated to poison hlm, or interfere with his health.” From this it follows that it is not necessary to prove that the adulteration is injurious to health, but simply that the article sold is “ not of‘ the nature dernaEded.’’ The magistrates’ decision was, there.fore, reversed, and a fine infIicted.-MedicaZ Examiner.His neighbours sold the compound, and he was obliged to sell it, Defendant was fined $10, and 12s. 6d. costs.THE ANALYST. 279 THE ALLEGED ADULTERATION OF FLOUR AT SELBY. TEE adjourned hearing of summon~es against Messrs. John Croysdale and Sons, flour millers, Wbitley Bridge, near Pontefract, who also occupy four stores at Selby, for having sold flour alleged to be adulterated with alum, took place at the Selby Petty Sessions yesterday, before Mr.B. Hemsworth (chairman), Mr. W. T. Smith, and Mr. J. Adams. The defendants were summoned on two separate informatioxis under the Sale of Food and Drugs -4ct, 1875, for having sold. flour mixed with alum, in one sample equal to 18 grains of alum to four pounds weight of flour, and in another sample to ten grains of alum to four pounds weight of flour.Superintendent Gill, the officer appointed under the Act, prosecuted; and Mr. Heaton Cadman, barrister (instructed by Messrs. Arundel and Son, Pontefract), appeared for the defendants. The case was reported in the Yercury when before the Court a week ago, and it may be remembered that a certificate from Mr. A. H. Allen, county analyst, was read, giving tbe result of his analyses of two samples of defendants’ flour, as set forth in the informations.A report was also read from three of the analysts at Somerset House, giving the result of their analyses of the same samples, which was to the effect that the sample marked 29 contained alumina equivalent to 9-9-10th grains of ammonia alum, and the sample marked 30 contained alumina equivalent to 21-1-10th grains of ammonia alum per four poucds of flour, Sample 29 according to their experience contained no more alum than was found in genuine flour, and with regard to the excess of alumina in number 30, the results of their experiments did not enable them to confirm tbat it existed in the flour in the form of alum.Mr. Cadman said that at the previous hearing of the case, in course of conversation with respect to the report from Somerset House, it was stated by one of the magistrates that if Mr.Allen’s certificate had been sent to the analysts there they would have used the word alum distinctly instead of alumina. Mr. Smith remarked that what he said was that Mr. Allen’s certificate bad not been sent to the analysts at Somerset House, or they might have used another name.Mr. Cadman said that at any rate the gentlemen engaged in the prosecution of this case had not the common honesty to tell them that a copy of Mr. Allen’s certificate had been sent to the authorities at Somerset House, and he now asked for the letter that was sent to be read. Mr. Hemsworth deprecated any imputation against the prosecution, as he was sure that Superintendent Gill had no feeling against the defendants.Mr. Cadman : I ask again, was a copy of Mr. Allen’s certificate sent to Somerset House ? Superintendent Gill : Undoubtedly, in accord- ance with a letter which I will read to you. Mr. Cadman said that at the former hearing it was certainly the impression of the Bench that merely a sample of the flour was sent to London, with a request to the authorities there to make a report on it.Now it seemed that a sample had been sent, together with the report of Mr. Allen. The authorities at Somerset Houlre were either to corroborate Mr. Allen’s report or repudiate it, and they said, ‘‘ The results of our experiments do not enable us to confirni that it (the alumina) exists in the form of alum.” R e wished to know whether a letter had been received from Somerset House since Nonday last.He explained that he had sent to Bomerset House particulars of Nr. Allen’s analysis, in accordance with a request from the analysts there. Since the last hearing he also sent a letter to Somerset Bouse, to which he received the following reply :- “With reference to the preceding letter, me have to state :-First. We are of opinion that the samples did not coutain alum, and we intended this to be understood by the terms of our certificate.Second. Both samples were very limited in quantity, that marked No. 30 barely weighing five ounces. Although we were enabled, with the quantity at our disposal, to prove by duplicate experiments the presence of an excess of alumina in No.30, and to satisfy ourselves of the absence of alum in both samples, it would have been more satisfactory to us to have had a larger quantity, that we might have been able to determine and state in our certificate in what form the excess of alumina existed in No. 30 flour.-(Signed), J. BELL, R. BANNISTER, and 4. J. HELM.” ‘Mr. Cadman said that the defendants had been brought into court to answer a charge of adulterating their flour with alum, and the analysts at Somerset House had certified that there was no alum present in it.That being so, was it necessary longer to take up the time of the Court ? The defendants would not have been charged, but for a mistake on the part of Mr. Allen, and because of an inaccuracy in his tests of analysis.Mr. Smith thought they should hear further evidence. It seemed to him as if the analysts at Somemet House were persons who were not chemists, and were simply creating confusion. He thought, on the other hand, that Mr. Allen had given his evidence in a proper and straightforward manner. He stated that he first tested the bread he had made from the sample of flour sent to him by the logwood test, which told him that there was something wrong with the flour.Having found this, he then ascertained the amount of alumina it contained by a process he had already described. Mr. Cadman : To put it shortly, you found something wrong by one test ; by another test you found what you call an excess of alumina, and then you put the two together and calculated alum.Is that so 3 Yes. Mr. Cadman: Did you by any process you used find one speck or tittle of alum as alum ? No, nor nobody else. When the case was called on, Superintendent Gill said that he had got a letter on thc previous day. The cross-examination of Mr. Allen, the analyst, by Mr. Cadman, was then resumed. Sobody ever found alum in bread as such.280 THE ANALYST.Mr. Hemsworth : The analysts at Somerset House agree as to the alumina, but they don’t say in what form it is. There is a property in the flour which ought not to be in it. Mr. Cadman : That excess of alumina might arise from the process of manu- facture, and that being so, under the words of the section the defendants cannot be convicted. They had heard that Egyptian wheat was very dirty.Well, the defendants had special machinery for scrubbing and washing the wheat. They brushed it to take off every bit of clay, but if any specks remained it might be sufficient to account for the presence of alumina, Mr. Eichard Banuister, one of the analysts at Somerset House, waa then called by Mr. Cadman, at the request of the Bench. His evidence was to the effect that the result of his and his colleagues’ analjsis of the flour was the same as Mr.Allen’s, but they came to different conciusions as to the excess of alumina, Mr. Allen said it existed in the form of alum, but they found that it was not alum. We want to know their opinion as to what that excess is. Mr. Hemsworth : Then what is it ? I am sorry I cannot tell you. But there is something in the flour that ought not to be ? There is more alumina, but it may come from clay or dirt, or something which we are unable to say.Mr. Allen, i n answer to the Bench, said he still maintained his belief that there wtu alum present in the flour. At the same time Mr. Bannister was quite justified in what he had said, because he had failed to get the precise result which he (Mr, Allen) got, He had the authority of Dr.Hassall that the logwood test sometimes failed. Mr. Bannister said that at the time they tested the samples sent to them they also tested 20 other samples of what they knew to be pure flour, and the result in all the cases was the same. They then added alum to some samples, and the test showed when the alum was present; so that he thought they were justified in concluding that the test was a good one.After this evidence, the magistrates retired and consulted, and on their returning into court, Mr. Hemsworth said that they had thought the matter over, and found the evidence so conflicting that they had decided to dismiss the information. Mr. Cadman said that had the bench not thought it right to dismies the charge at that point, he would have called witnesses to prove that it was inpossible for a miller to put alum into the flour.Mr. -Hemsworth : Let’s say no more about it, Mr. Cadman applied for costs, but the bench would make no order .- Leeds Mercury, ARSENIC IN VIOLET PowI)ER.--dt Epping Petty Sessions, on May 24th, Henry George King, whole- sale chemist, of 14, Abbott Street, Xingsland Green, was charged with having killed one Eliza Sear, and also with having unlawfully sold and delivered to divers persons quantities of violet powder, containing large proportions of white arsenic and other ingredients, with the intent that it should be applied to the bodies of children of tender years.Mr. Poland opened the case on behalf of’ the Treasury, and John Nottage and Emma Grout, two grocers, were called to prove the wholesale purchase of violet powder, by them, from the defendant, and several women were called who proved having purchased packets of violet powder from the8e grocers, and using it to their children, several of whom died in consequence.Mrs. Sear lost two children, one in MSrch, 1877, and another in February, 1878. Her evidence, as to the latter child, was that it was born on the 13th February, and on the day of its birth she sEnt to Miss Grout’s shop for a packet of the powder, which was used, and the infant died on the 18th of the same month. I t was a healthy child at birth, but its face turned very red, the skin broke out all over the face and neck, and the more the redness and soreness increased, the more the powder was used, in the belief that it would do good. Soon afterwards the lower parts turned black ; this appearance rapidly extended to the body generally, ard on the day of its death it gave out from the nose and mouth a ‘* kind of black blood.” Its agony was awful, and during the night before its death it screamed continuously.-The inquiry was adjourned till the 31st.

ISSN:0003-2654    

DOI:10.1039/AN878030278b

出版商:RSC    

年代:1878

数据来源: RSC