摘要:

THE ANALYST. SEPTEMBER, 1898. OBITUARY. THE LATE JOHN A. R. NEWLANDS. IT is with very deep regret that we have to record the death, on July 29, at Clapton, of one of our most respected vice-presidents, Mr. J. A. R. Newlands, who was in the sixty-first year of his age. Mr. Newlands’ memory will always be associated with the discovery of the “Periodic Law,” which was afterwards worked out more fully and boldly by Mendelkef, Lothar Meyer, and De Chancourtois. Mr. Newlands’ first comrnunication on that subject was made to the Chemical Society in 1863 in the form of a note, and in 1866 he presented to that Society a paper entitled (‘ The Law of Octaves, and the causes of the Numerical Relations amongst the Atomic Weights,” in which his ideas were further elaborated. His views were received at that time with sa much incredulity and even derision by the Chemical Society that they never found a place in its Journal, the subject being deemed of a too theoretical nature to merit publication.Nearly twenty-five years later, however, in 1887, Newlands’ work met with authorita- five, though tardy, recognition, for in that year the Royal Society awarded him the Davy Medal “for his discovery of the Periodic Law.” I n the region of applied chemistry he had for many years past devoted his energies mainly, in connection with his well-known brother, Mr. B. E. R. Newlands, to questions connected with the sugar industry. Mr. Newlands, whose ancestors on the father’s side were Scotch, and on the mother’s Italian, was of a genial and enthusiastic nature; he was an earnest supporter of reforins in his own country, and even went so far as to serve as an English volunteer under Garibaldi in the war for the liberation of Italy. We feel that we have lost in Mr. Newlands a remarkable and original man, and one whose affable and kindly disposition had endeared him to the hearts of all who knew him.

ISSN:0003-2654    

DOI:10.1039/AN8982300225

出版商:RSC    

年代:1898

数据来源: RSC

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THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. ON CHICORY, AND VARIATIONS I N ITS COMPOSITION BY BERNARD DYER, D.Sc. (Read at the Meeting, Jzini 1, 1898.) DISCBEPANCIES between analysts in estimating the proportion of chicory in mixtures of chicory and coffee appear to be unfortunately frequent, and these may be attributed to varying assumptions as to the composition of the chicory present. As there is no satisfactory mode of separating coffee and chicory, the analyst is driven to base his calculations mainly upon the proportion of soluble matter in the sample, and on the assumed average proportions of soluble matter in coffee and chicory. Most analysts experimentally deduce their estimate of soluble matter, and hence the proportions of coffee and chicory, from the density of 10 per cent.infusion of the mixture, and a great many data are on record of the densities of such infusions of coffee and of chicory, but most of them are old. Some analysts-E. W. T. Jones, for example- prefer to evaporate a meaeured portion of the watery extract and actually weigh the soluble residue. Alfred Smetham in 1883 (ANALYST, vii., 73) suggested thoroughly boiling out the sample with water, washing, drying, and weighing the insoluble residue on a counterpoised filter. It presumably makes but little difference which method is used, provided that the same mode of working is adopted for comparative purposes ; but, as since the publication of Mr. Smetham’s paper, I have myself always determined the insoluble matter directly, and the soluble matter by difference, it is in this forin that I now propose to record some results of a recent investigation into the composition of the chicory at present in the market.Mr. Bannister, in his evidence before the late Select Committee on Food Products Adulteration, in reply to a question froin Sir Charles Cameron, endorsed an experi- ence, attributed to Mr. Hehner, to the effect that the soluble matter in chicory appeared to have increased during the last ten or fifteen years, a fact which Mr. Bannister attributed to ‘‘ difference of growth.’’ My own experience confirms that of Mr Hehner and Mr. Bannister, but I think there is no reason to suppose that the difference is due to methods of growth. I t is more easily and probably accounted for by a custom of less highly roasting. I n 1883 I examined six samples of chicory obtained from various sources, with a view to their being representative of the chicory then in the market, and found that, calculated on the samples dried at 212” F., the mattek insoluble in water, after exhaustively boiling and washing, weighed on the average 33 per cent., the variations being from a little over 30 to a little over 36. I n 1895 I had occasion to examine a sample of chicory stated to be representative of that which was in use by a very large firm of wholesale grocers, and found only 23 per cent.of insoluble matter in the dried sample. During the present year I took steps to obtain from several thoroughly repre- sentative wholesale houses samples of the chicory in current use, in all cases requesting to be supplied with samples representing any different grades of roasting or colourTHE ANALYST.227 that might be in current use, I t may be stated that the percentage of moisture varied in extreme cases from 1 per cent. to 4 per cent., but the following results are all calculated on the dry substance. They show the total matter insoluble in water (inclusive of mineral matters), the ether extract, the nitrogen, the total ash, the ash soluble in water, and the sand. Chicory “ nibs,” described ... Chicory ( ( nibs,” described as “ medium roast ” as ( ( dark roast ” ... Ground chicory . . . ... 7 7 1 9 ... 7 ) 9 ) ... ,) 1 ) ... >, >, ... ... 9 , 7 9 ... > Y ,) ... ... 7 , 7 , ... 9 9 Y , ... ... . . I ... ... ... Total Matter Insoluble in Water.Per cent. 22.40 50.30 22-27 2 1.50 35-50 37.80 22.77 22.50 23.50 22-50 22-63 Ether Extract. Per cent. 2.57 2.43 2.17 1-90 3.43 3.87 3-17 3.67 2 960 2.60 2.57 Nitrogen. Per cent. 1.53 1.67 1.33 1.34 1.50 1.52 1.25 1-23 1.29 1-29 1.29 Total Ash, Per cent. 4 63 4-70 5.53 5.23 5-13 8-23 5-13 5.73 5-63 5-33 5.70 Ash Soluble in Water. Per cent. 2 30 2 99 2.43 2.07 2-57 1-60 3.30 3.23 2.97 3.20 2.60 Sand. Per cent. 0.70 0.30 1.43 1 *43 0-77 3.97 1.60 1.63 1.47 1-47 1.47 I t will be seen that in eight out of the eleven samples the matter insoluble in water ranged from 21.50 to 23-50 per cent. One sample contained 35.50 per cent., one 37.80, and one 50-30 per cent. of insoluble matter. I have myself made no experiments to ascertain what percentage of insoluble matter is indirectly indicated by the figures usually assumed to represent the specific gravity of a 10 per cent. infusion of chicory, but I believe they may be taken as roughly corresponding to about 70 per cent.of soluble matter and 30 per cent. of insoluble matter, corresponding to the 70 per cent. of soluble matter assumed by E. W. T. Jones as representing chicory in his direct method of determination. There is no doubt that, if the samples I have recently obtained fairly represent the chicory at present in the market-and I have everyreason to think they do-any estimates deduced from density determinations with the aid of the older data would result in too high an estimate of the proportion of chicory, since they assume a much less proportion of soluble matter than that which is present in the greater part of the chicory at present in use.I t is quite true, on the other hand, that with some kinds of chicory at present in use, reliance on the old figures might cause an error on the side of considerably underestimating the proportion of chicory ; but an underestimate of the inferior article is, from the public analyst’s point of view, obviously a matter of far less moment than an overestimate, which would reflect unjustly upon a seller of the article. I t is indeed remarkable that, after attention had been drawn to the matter, the old figures should have still remained in use. The following experiments were made with the sample marked ‘( chicory nibs, medium roast,” which gave originally 22.40 per cent. of insoluble matter.A portion22H THE ANALYST. of the sample, after grinding and drying, was placed in a platinum capsule over a very ~ Q W argand flame, and gently heated with thorough stirring until it had lost about 5 per cent. of its weight. A similar portion was similarly treated until it had lost about 10 per cent. of its weight. Calculating on the original weight taken, the proportion of insoluble matter in the first experiment rose 'from its original figure of 92-40 per cent. to 2850 per cent., and during the second experiment it rose to 41.50 per cent. Seeing that there was a loss in the two experiments of 5 and 10 per cent. respectively, the percentage of insoluble matter in the actual roasted chicories would be 30 per cent. as the result of the first experiment, and 46 per cent.as the result of the second experiment. I n neither case was there any appearance which could be described as that of burning. It seems clear, therefore, that the percentage of insoluble matter is mainly a function of the mode and duration of roasting. I t may be of moment to mention here that, on exhaustive boiling, Smetham, in 1882, found a number of coffee samples to contain about 75 per cent. of matter insoluble in water. Three samples of coffee of known purity which I examined in 1883 by this method gave from 72 to 73.3 per cent., averaging 72.9. In 1895 I made determinations in a batch of 16 samples of pure coffee, which showed a range of from 69.4 to 74.3 per cent., averaging 72 per cent. I n 1897, 27 pure samples ranged from 71.8 to 75.9 per cent., averaging 73.7 per cent.I have found a8 little as somewhat over 68 per cent, of insoluble matter (on the dry sample) in a ground coffee in which no chicory was discernible, and which on all other grounds appeared to be genuine; but it is quite possible that in this, 5\18 in some other cases somewhat approximating to it, sugar may have been used in roasting the coffee, though no evidence was obtainable that such was the case. DISCUSSION. Rfr. CASSAL said that quitefive years previously he had found as much as 79 per cent. of soluble matter in chicory, and had in consequence been in the habit of depend- ing upon the number 79, which almost exactly corresponded with the minimum figure now given by Dr. Dyer for insoluble matter, viz., 21-5 per cent.With regard to the samples yielding 50.3 and 37.8 per cent. of insoluble matter, it was evident that such cases were altogether abnormal, and that what could properly be regarded as chicory " was not being dealt with. I n a substance like chicory, continued roasting necessarily increased the proportion of insoluble matter. lfr. CHATTAWAY inquired whether the tinctorial power increased as the roasting was carried to a higher degree. A highly caramelized sample might be expected to yield a darker solution than one that has been less highly roasted. Mr. CHAPNAN observed that the relative proportions of soluble and insoluble matters would depend to some extent, not only upon the actual temperature, but also upon the conditions under which the roasting process was carried on.I n roasting a substance like chicory, containing all kinds of caramelizable bodies, soluble compounds would be formed up to a certain point, after which such soluble compounds would to some extent be decomposed, with the result that the soluble matter, after reaching a maximum, would diminish again. I n the manufacture of caramel from sugar, if the heating mere effected too quickly, or the caramelized sugar poured into water a tTHE AN.ALYST. aag too early a stage in the process, the maximum coloring power and soluble extract would not be obtained. It was, he thought, to be expected that considerable varia- tions from what might be called the normal extract should from time to time be observed. hlr. CASSAL added that he thought the figure usually taken for soluble matter in pure coffee, viz., 24 per cent., was sometimes. too easily accepted. He had himself found as much as 29 per cent. of soluble matter in genuine coffee. Dr. DYER said that he had once found 68 per cent. of soluble matter in a sample of coffee that was undoubtedly free from chicory. The sample, however, might have been roasted with sugar, and this was difficult to detect. Dr. VOELCKER asked how much oil chicory usually contained. Dr. DYER said that the oil was from 2 to 3+ per cent., but it did not seem to have any relation to the other constituents. In the sample containing 50 per cent. of insoluble matter the oil was 24 per cent. ; in the two lowest samples it was 2+ and 3& per cent. respectively. The highly roasted samples were somewhat darker than the others, but in the case of a mixture the colour of the coffee itself would also be liable to variation,

ISSN:0003-2654    

DOI:10.1039/AN8982300226

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

THE AN.ALYST. aag ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Detection of Annatto and other Coloring Agents in Milk. J. Froidevaux. (Ann. Chim. AmZyt., vol. iii. [4], pp. 110-114.)-0f the various coloring agents added to milk, annatto and O T C L ~ L ~ C III. Poirier impart a flesh tint, saffron a slightly orange yellow, carrot an orange-yellow, and turmeric a slightly greenish-yellow tinge to the liquid. The last-named may be detected by the change to brown-yellow ensuing on the addition of ammonia. Hydrochloric acid (5 per cent. by volume) deepens the shade due to vegetable coloring matters and produces a clear rose coloration in presence of orange III. The detection of these colorants is facilitated by coagulating the casein with a little rennet at 25" to 30" C.during fifteen hours, the colour lakes thus formed being more pronounced in shade-except in the case of orarzge III..-than when in solution. Saffron and turmeric will impart a yellow stain to white filter-paper immersed in the whey for four days, the former colorant being distinguishable by the yellow stain-turning to slightly orange-yellow in presence of very dilute (e.g., 2 per cent.) sulphuric acid-which it gives to filter-paper on immersion for four days in the liquid left after treating the niilk with an equal volume of Adam's reagent,* and removing the * This reagent, which is employed by Adam in his process for estimating fat in milk, consists of : Alcohol (specific gravity 0.96") . . . . . . . . . . . . . . 533 C.C. Ammonia (specific gravity 0,925) .. . . . . . . . . . . . 30 C.C. These are made up to a litre with distilled water, and then 1100 C.C. of ether washed with water added.230 THE ANALYST. upper ethereal layer of dissolved fat. Under the same treatment annatto gives an orange-red, changing to blue under the influence of 1 drop of strong sulphuric acid, and a bright rose colour in presence of a 2 per cent. solution of acid. c. s. Detection of Annatto in Milk. A. Leys. ( A m . Chim. Analyt., vol. iii. [ 5 ] , pp. 149-151. See preceding abstract.)-The presence of this substance in milk can be detected more rapidly than by the method proposed by Froidevaux, if, after treating the suspected liquid with Adam's reagent and removing the supernatant ethereal solution, the casein in the lower layer be precipitated by the gradual addition of 50 per cent.of a 10 per cent. solution of sodium sulphate, without agitation. This treatment leaves the coloring matter in solution, from which it may be extracted by agitation with colorless aniyl alcohol, the emulsion thus formed being dissipated by slowly heating the mixture to 80" C. The reddish alcoholic solution is evaporated to dryness and redissolved in hot, slightly alcoholized ammoniacal water, a strip of bleached cotton-cloth being immersed in the liquid, which is then concentrated on the water-bath. The cotton absorbs the coloring matter, and, after being lightly washed, is immersed in a weak acid (e.g., citric acid), which in the case of annatto immediately changes the colour to a clear rose.This reaction does not ensue in the case of saffron, turmeric, etc., or in uncolored milk, notwithstanding that the cotton is dyed. c. s. New Reactions for the Detection of Aldehydes in Alcohols. C. Istrati. (Bzdletiizzil Societatii de Sciinte, Bucuresci, vol. vii. [2], pp. 163-170.)-The method adopted by Barbot and Jandrier (ANALYST, xxi., 295) can be improved by taking exuctly 2 C.C. of the impure alcohol, adding thereto 0.2 C.C. of a saturated alcoholic solution of the reagent, and, after mixing the two, running in exactly 1 C.C. of sulphuric acid from a pipette, the tube being held at an angle of 45". The coloration produced at the moment of contact is noted, as is also the change after a lapse of half an hour. After partial agitation, to increase the surface of contact, the coloration is again noted at the end of half an hour, and once again half an hour after complete agitation.The liquid is then mixed with 10 C.C. of water, and examined half an hour and twenty-four hours later, the latter observation being estremely useful, as any precipitate formed will have had sufficient time to settle doym. Greater uniformity of conditions is ensured by the use of the alcoholic solution of the reagent, but such solution, being unstable, must be freshly prepared, I n the case of liquid reagents, such as guaiacol, 1 drop is used instead of 0.2 C.C. The reactions given by ten other substances than those examined by Barbot and Jandrier are tabulated below, those printed in italics referring to dilutions of 1 The remainder refer to iom and those in thick type to dilutions of -- 1 100,000 1 -- strength :Pyrogallol - - P-naphthol - - a-naphthol - .Phenylhydrazine - roquinone - i!2Lcol - - Orcine - - Vanillin - - Morphine - - Codeine - - Thymol - - P-orthonaphthoic acid - - Resorcin - - Protogallic acid - Phenol - - Phloroglncin - Gallic acid - - Camphor - - Brucine - - Methttnal. Orange-y ellow, with green fluorescence ; red pp. with water - Light brownish- green Reddish-yello w - - - Violet Violet -yellow - Brown-yellow ? - Greenish-yellow, disappearing with water - Grecjnish-yellow Golden- yellow Ethannl. Reddish- yello w Yellow Reddish- yellow Yellow Rose - yello w Brown-yellow Blackish-green ; grey-blue pp. with water - - Valeral. Orange-red Yellow Orange-red Golden -yell0 w - - - - YeUozu (slow) Acrolein.Brown-red Golden-yellow - Reddish -- - - Green. (1 drop of reagent) Golden-yellow, green Auores- cence - Furfurnl. Brown-yellow, turning to black Carm&e-red Red, nearly black Green, more characteristic than the othera - - Brown- yellow - - Broumkh-yellow (slow) Brown-yellow, turning to black Yellow B r o wiz-red, turning to black - Bcnealdehydc. Bro wn-red Crimson Idem. Brownish-red, better than with - Brown-red, changing to gree Orange- yello w - Yellow -. - Rose, browit,, violet (very slow Methylttl. Carmine-red Orange-red ; strawberry pp. with water Yellow, red above, green be- low with water - I Violet-red - I Heliotrope-violet - - Greenish -yellow, disappearing with water Acctnl. Orange-yellow Orange -yell0 w - Blackish-green ; blue pp.with water - cj w M c. 8. r23'2 THE ANALYST. Estimation of the Dry Extract in Wine, A. Cellerin. (Bull. du Ministhre de I'Agriczdture, through Ann. Clzim. AizaZyt. , vol. iii. [6], pp. 204-206.)-The period of evaporation may be reduced from the three days required for the Magnier vacuum method (ANALYST, xxi., 66) to seven and a half hours by employing a temperature of 80" C., and a U-tube apparatus with limbs of unequal diameter, the narrow one being connected with a bulb-tube containing sulphuric acid, and the larger one half filled with a piece of fine sponge, and fitted with an effluent tube for the condensation of the evolved vapour. This apparatus is dried by heating for about an hour over the boiling water bath until the difference between two weighings, at intervals of half an hour, does not exceed 1 milligramme.Ten C.C. of wine are then introduced by means of a pipette and absorbed by the sponge, and the tube is heated on the water- bath at 80" C.-a current of air being passed continuously through the apparatus- until found to be perfectly dry below the cork and of constant weight (with a latitude of 1 milligramme at half-hour intervals). The increase in weight represents the amount of dry extract in the wine. At 80" C. the loss of glycerol by evaporation does not exceed 0.05 per cent., but this temperature should not be exceeded. The results obtained by this method are fairly constant, and are only 0.5 gramme per litre inferior to those yielded by evaporation in vacuo. c. s. Action of Charcoal Decolorizers on Wines.H. Astruc. ( A m . Chim. A?znZyt., vol. iii. [6], pp. 183-191.)-As the result of experiments with ten kinds of charcoal decolorizers, comprising crude and purified bone blacks, lamp blacks, and vegetable charcoal, the author concludes that there is little difference between the crude and purified animal blacks so far as their orgauoleptic and colorimetric influence on wine 'is concerned, the purified kinds being, however, slightly preferable. Their decolorizing power is best preserved by storage in a moist condition after washing. All the decolorizers absorbed a little alcohol (0.4 to 1.5 per cent. out of a, total of 7.8) ; a small proportion of the total acidity; 0.5 to 2.65 per cent. of the glycerol (total, 4.5 per cent.), and 0.95 to 2.65 per cent.out of a total of 3-45 per cent. of tannin, besides extracting coloring matter.. The crude bone blacks are distinguished from the purified blacks and vegetable charcoals by removing almost the whole of the tartrates and a larger proportion of glycerol, and especially by increasing the amount of mineral matter in solution to double its original weight, the increase being entirely in insoluble ash-constituen ts (chiefly lime and phosphoric acid), whereas the soluble portion is diminished. The decolorizing power of the vegetable blacks is low, and necessitates the use of a twofold or triple quantity, the effect of which on the chemical constitution of the wine is greater than that of a suitable amount of animal black. The flavour of the wine is also moreseriously affected than by the latter.c. s. The Estimation of Oil i n Emulsions. Dr. Schneegans. (Jounz. Pharm. d'dlsace-Lorrai?ze, 1897, p. 323 ; through Rev. Clzinz. Analyt. Appl., vol. vi. [8], p. 130.) -Three hundred parts of the oily emulsion under examination are evaporated withTHE ANALYST. 233 30 parts of white of egg and coarse sand, 50 parts of anhydrous sodium sulphate being added and the evaporation completed, with continued stirring to prevent caking. The residue is pulverized and extracted with ether, the fat being recovered by evaporating the solvent in a tared beaker. c. s. Acid Glycero-phosphates. Adrian and Trillat. (Jounz. P ~ c L I Y ? ~ . Chim., 1898, vii., 527.532.-The acid salts of glycero-phosphoric acid can be prepared by decom- posing a normal glycero-phosphate with sulphuric acid : /O - Ba - 0- OP, 2PO-O/ /O\Ba + H2S0, = BaSO, + PO -OH ____--- ~ \OC,H,( OH), \OC,H5(OH), (OH),C,H,O/ ' or by double decomposition between a soluble sulphate and an acid glycero- phosphate : - - /'OH Ba[ OPO<~~H,(oH),] , + MgSO, = BaSO, + Ng[ OPO \OC,H,(OH), I, They are employed in the preparation of organic glycero-phosphates, such as those of quinine, cocaine, etc.The method of determination given by the author is to dissolve from 1 to 2 gramrnes in 50 C.C. of water previously boiled, and to titrate the filtered solution with normal potash, using phenolphthalein as indicator. The amount of acid salt is then calculated from an equation like the following for the barium salt : /OK . \ 0 C, H Ij ( 0 H ) 2 /'\Ba + PO-OK \0C:$x5( OH), ] +2KOH=H,O+PO O/ Cf.ANALYST (this vol., 45). c. A. 11. Estimation of Iodoform. G. MeillSre. ( 6 7 z n . Chim. Awdyt., vol. iii. [5], pp. 153, 154.)-The difficulties encountered in the estimation of iodoform in presence of organic substances may be overcome by the following method : The iodoform is placed in a flask where it is treated with 25 C.C. of pure nitric acid (free from chlorine), followed by a slight excess of silver nitrate (1.75 gramines per 1 gramme of iodoform), this order being observed in order to prevent the explosion resulting from the contact of iodoform and the silver salt in the dry state. The flask being connected with a Liebig bulb-tube containing silver nitrate solution, the contents are slowly heated, without actually boiling, for ten minutes, after which the temperature is raised to effect the decomposition of the iodoform.When nitrous fumes cease to be evolved, the liquid, after dilution to 150 c.c., is heated until clear, the precipitate is collected on a tared filter and washed, being finally dried at 100" C. Should the nitrate solu- tion in the bulb-tubes become turbid, it must be united to the contents of the flask. In two determinations made with 1 gramine of iodoform an average of 1-7835 grammes of silver iodide was obtained, the theoretical yield being 1.789 grammes. c. s234 THE ANALYST. TOXICOLOGICAL ANALYSIS. A Strychnine-like Alkaloid found in a Corpse, P. Mecke. (Phamz. Zeit., 1898, xliii., 300; through Chem. Zeit. Rep., 1898, 128.)-During the examination of a partially decomposed body the author met with an alkaloid which chemically might easily be inistaken for strychnine, but which physiologically did not injure frogs, had scarcely a bitter taste, and did not produce the least effect on animals when injected subcutaneously, With picric acid it gave a yellow crystalline precipitate, becoming violet on treatment with sulphuric acid and bichromate. Bichromate alone produced a yellow crystalline precipitate, changing to blue with sulphuric acid. Bichromate and acid together yielded a blue, afterwards a reddish, colour. Ferricyanide gave a yellow precipitate, turned violet by acid. On the other hand, chlorine-water gave (as with strychnine) a milky liquid, but when after evaporation the residue was treated with ammonia it became a dirty green. I t dissolved in sulphuric acid to a yellowish liquid, afterwards changing to cherry- and rose-red. Frohde’s reagent dissolved it, giving a dull violet colour, which finally became olive and then green. The substance is not the saine as that discovered under similar conditions by Amthor in 1887. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN8982300229

出版商:RSC    

年代:1898

数据来源: RSC

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234 THE ANALYST. ORGANIC ANALYSIS. The Examination of Semi-Woollen Textile Fabrics. S. KapK (If. Text, 1898,193. Through Zeit. c ~ q c z u . Chent., 1898, 452, 453)-In the author's opinion all the methods proposed for determining the proportion of cotton and wool in a inixture are inaccurate. He recommends the following process : Five grammes of the sample are extracted with ether for the determination of the fat. The residue is well stirred for thirty minutes in a mixture of 3 parts of hydrochloric acid with 100 parts of water, which is brought to the boiling-point before the introduction of the substance, and the flame subsequently withdrawn. It is then boiled with water for fifteen minutes, washed free from hydrochloric acid, dried for two hours at 100" C., and left exposed to the air for about twelve hours for the fibres to assume their original moisture.The loss in weight gives the amount of weighting material, coloring matter, etc. This treatment also removes certain natural constituents of the wool and cotton, whilst the fibres themselves are attacked, though but slightly. The residual fibres are separated by heating them to the boiling-point with 250 C.C. of water containing 5 grammes of sodium hydroxide. The cotton which is left is collected on a filter, washed first with a litre of water, then with half a litre of water slightly acidified with hydrochloric acid, and finally with water until free from acid. I t is then dried for two or three hcurs at 100" C., allowed to stand exposed to the air for about twelve hours, and weighed. The addition of 4.5 per cent.to the weight obtained gives the amount of cotkon-fibre in the mixture, this correction being based on the results of experiments which showed that pure cotton-wool on treatment with soda as described above loses almost exactly that amount. C. A. M.THE ANALYST. 235 Estimation of Nicotine in Tobacco. C. C. Eeller. (Ber. Pharm. Ges., 1898, viii., 145 ; through Clzenz. Zed. Rep., 1898, 159.)-Six grarnines of dried tobacco are repeatedly agitated during half an hour with 60 grammes of ether, 60 grainmes of petroleum spirit, and 10 C.C. of 20 per cent. aqueous caustic potash. After standing three or four hours, 100 grammes of the ethereal liquid (equal to 5 grammes of tobacco) are filtered off, a powerful current of air is driven through it for one or one and a half minutes to remove the free ammonia, 10 C.C. of alcohol, 1 drop of a 1 per cent.solution of eosin B, and 10 C.C. of water are added, and the whole' is well shaken. A slight excess of decinormal HCI is then run in, and the liquid is titrated with decinormal ammonia. One C.C. of :& HC1 equals 0,0162 gramme of nicotine. F. E.. L. Detection of Acetone in Urine. B. Studer. (Schzoeitz. Woclzenschr. Chem. Pharm., 1898, xxxvi., 149 ; through Clzcnt. Zeit. Re?., 1898, 127.)-The author's process is a combination of the Legal and the Lieben-Dragendorff methods. Fifty C.C. of urine and 5 C.C. of dilute sulphuric acid are distilled in a fractionating flask until about 3 C.C. have passed over. The distillate is mixed with 6 to 10 drops of a freshly-prepared 10 per cent.solution of sodium nitroprusside and 1 to 2 drops of caustic soda to make it alkaline. I n the presence of acetone the liquid becomes purple-red; in its absence, yellow or orange. If a pale red is produced, suggesting a, trace of acetone, 6 or 8 drops of glacial acetic acid are added, when an intense aine- red colour confirms the test ; while, if the liquid turns yellow again, acetone does not exist in the urine. F. H. L. Estimation of Uric Acid, based on the Insolubility of Ammonium Urate. 3. Triollet and J. Eury. (Union Pharmaceut., May 5, 1898; through Rev. Chinz. Analyt. AppZ., vol. vi. [lo], p. 166.)-The authors recommend the employment of the method proposed by Otto Folin, 100 C.C. of urine being rendered slightly alkaline by agitating with 10 grammes of ammonium sulphate, and the precipitate, collected after two hours' standing, washed with 50 C.C.of a 10 per cent. solution of the same salt. I t is then redissolved in (slightly alkaline) boiling water, the solution diluted to 100 C.C. after cooling, and treated with 15 C.C. of sulphuric acid, which causes the temperature to rise to 55" to 60" C. Titration is effected by the Hopkins method with 2G normal potassium pernianganate until a persistent rose coloration ensues, 1 milligramme being added to the result as correction for loss due to the solubility of the ammonium urate. c. s. Colorimetric Estimation of Aceto-acetic Acid in Diabetic Urine. F. Martz. (U~zion Phamzncez~t,, May 15, 1898; through Rev. Clrim, Analyt.Appl., vol. vi. [lo], pp. 165, 166.)-The reagent employed is ferric chloride, which gives a violet colora- tion with aceto-acetic acid in urine before, but not after, the latter has been boiled. In cases where the coloration is due to this acid alone 5 C.C. of officinal ferric chloride are added to 100 C.C. of urine, and the filtered liquid is placed in a test- glass, where it is compared with 20 to 50 C.C. of a solution of 1 gramme of aceto-236 THE ANALYST. acetic acid in 100 C.C. of water, plus 5 C.C. of the reagent, the test-liquid being made up with water until both liquids are of equal depth of colour. I n presence of other substances giving the same reaction two determinations are necessary, one previous to and the other after boiling the urine, the coloration due to the acid in question being calculated from the difference between the two results.c. s. Detection of Glucose by means of Litmus. A. M. Julhiard. (hzn. Chinz. Analyt., vol. iii. [5], pp. 154, 155.)-Litmus being (like indigo carmine) decolorized by glucose in an alkaline solution, the author recommends the following as a ready test for the detection of that sugar in urine. A little sodium carbonate and a few drops of litmus tincture being added to the suspected urine, the liquid is heated to boiling, whereupon if containing sugar it will assume a dirty yellow colour. The reaction is more apparent after the precipitate has settled down, but it is not permanent, the blue coloration gradually reappearing on exposure to the air. Litmus-paper is also decolorized under the same conditions, and may therefore be conveniently employed instead of litmus solution.c. s. The Estimation of Succinic Acid in the presence of Tartaric and Lactic Acids. (Joz~m. Pharm. Chim., 1898, vii., 417, 418)-This is based on the difference in solubility of the silver salts of the three acids. On adding a concentrated solution of silver nitrate to a solution of their neutral soluble salts, the succinic acid is precipitated completely, the tartaric acid partially, while the lactic acid remains in solution. I n the determination, the solution containing the three acids is exactly neutralized with decinormal potash, an excess of a concentrated solution of silver nitrate added, and the precipitate filtered off and washed free from silver.Only the silver succinate is left on the filter, for the washing removes the silver tartrate completely. The precipitate is washed into a flask, and two drops of a solution of potassium chromate added, which decompose the silver succinate with the formation of silver chromate. Decinormal sodium chloride is then added, until the precipitate becomes white and the liquid assumes a yellow tint, and finally the excess of'sodiuin chloride is titrated with decinormal silver nitrate. By subtracting the number of C.C. used in the last titration from the amount of sodium chloride taken, the volume of decinormal silver nitrate required to precipitate the succinic acid present is obtained. One C.C. of the silver nitrate corresponds to 0.0059 gramine of succinic acid. F. Bordas, Joulin, and Raezkowski.C. A. M. Quantitative Estimation of Paraffin in Petroleum and Lignite-tar Dis- tillates. D. Holde and L. Allen. (Mittheil. Kgl. Techn. Versuchsanst., 1898, No. 2 ; through Chem. Rev. Fett- u. Haw-Ind., vol. v. [6], pp. 112-115, 171, pp. 131-134.)- The present investigations were designed to ascertain the suitability of the alcohol- ether method for a wider series of oils than those previously tested therewithTHE ANALYST. 237 (I'llittJ~eiZz~?zgen, 1897, p. 211). The Aisinmann alcohol method was also critically examined. The apparatus for cold filtration was altered to the forin and dimensions shown in the annexed figure and acted well, enabling a constant temperature of -20" to - 21" C. to be maintained with one charging long enough for the performance of a complete quanti- tative determination.The practice of ascertaining beforehand the minimum quantity of alcohol-ether necessary for dissolving the oil, and of effecting the solution of the latter at room temperature, greatly facilitates the subsequent operations and the separation of the paraffin, 0.4 per cent. of which was by this means recovered from a paraffin-oil wherein it was ohherwise quantitatively undeter- minable. I n applying the method to oils rich in paraffin, from 0-5 to 2 grammes of substance were dissolved in a minimum quantity of sulphuric ether, the solution clarified by the addition of an equal volume of absolute alcohol, and after insertion in the cooling-apparatus and dilution (if necessary) until filterable by the aid of alcohol-ether (1 : 1), the paraffin was separated by filtration.The filtrates were then evaporated and treated as before, in order to recover any residual dissolved paraffin. I n all cases the paraffin was dissolved in petroleum spirit (b. p. 50" C.) and carefully re-evaporated, any moisture present being removed by evaporation with a little absolute alcohol. As regards the solubility of paraffin in absolute alcohol, this was found to be greater than assumed by Aisinmann, 100 parts of solvent taking up 0.10 to 0.19 part at 20" C., and 0.015 to 0.017 part at -15" C. I n alcohol-ether the solubility is greater (0.03 to 0.06 per cent. at - 19" C. to - 20" C.), and in both cases it varies inversely with the melting-point. The presence of oil in the alcohol-ether mixture, however, reduces the solvent power of the latter for paraffin, so that this source of error is counteracted when the method is applied for the estimation of paraffin in mineral oil distillates, the loss by solution ranging from 0.2 per cent.in oils containing 1 to 5 per cent. of hard paraffin, to an average of 1 per cent. in oils richer (30 to 90 per cent,) in that substance. For soft paraffins the results require to be compared with those obtained by treating mixtures of known paraffin content. The objection urged by Eisenlohr against methods employing a higher tempera- ture than 100" C. for drying the paraffin-on the ground that soft paraffin suffers loss by evaporation under such conditions-was investigated, but found to be baseless so far as the alcohol-ether lllethod is concerned, the abbreviated (quarter of an hour) exposure to 105" C.resulting in a loss so small as to be negligable in technical analyses. On the other hand, a sample of paraffin supplied by Eisenlohr was found to lose considerably by this treatment, and it is therefore proposed in such cases to dispense with the evaporation at 105" C., and merely heat on the water-bath until the odour of the solvent disappears, the drying being completed in the desiccator. Interesting results were obtained by applying the alcohol-ether method to lignite-238 THE ANALYST. tar distillates, the figures obtained showing a yield of paraffin (m. p. 26" to 53" C.) from 1 to 3 per cent. higher than actually furnished in the refinery ; and in one case the accurate characterization of the practical value of the material was shown by the recovery of 5 per cent.of worthless parafin (m. p. 26" to 27" C.) from a distillate from which none could be separated in the factory. These experiences controvert Eisenlohr's opinion that the method is unsuitable for lignite-tar distillates. An investigation of Aisinmann's alcohol method showed that accurate results are only obtainable when the paraffin greatly predominates (e.g., 80 per cent.) in the mixture, and even then the alcohol-ether is preferable on account of its greater ease in manipulation. c. s. The Reactions in Hubl's Method of Iodine Absorption. J . J. A. Wus. (Zed. angew. Chenz., 1898, 291-297.)-Ephraim (ANALYST, 1895, xx., 176) attributed the additive power of Hubl's solution to the presence of iodine monochloride, and described a method of determining the halogen absorption of fats by means of a solution of that substance.The author finds that the formation of the iodine chloride takes place in accordance with the equation and considers that the equivalence of these substances is proved by the fact that it is possible to prepare a solution giving the same results as that of Hubl, by dissolving mercuric iodide in an alcoholic solution of iodine chloride. The iodine chloride thus formed reacts with the water of the alcohol yielding hypoiodous acid and hydrochloric acid and this acid is continually being slowly decomposed into iodic acid and free iodine, which substances in the presence of hydrochloric acid in alcoholic solution again produce iodine monochloride, so that a complicated equivalence results.On adding the potassium iodide and water to the solution before titration, the following reactions take place : (1) HgC1, + 41 = HgI, + 2IC1, (2) IC1+ H20 = HCl+ HI0 ; (3) ICl+KI=KC1+21; (4) ( 5 ) HCl+ HI0 + K I = KCl+ H,O + 21 ; 5HC1+ HIO, + 5KI = 5KC1+ 3H20 + 61. Theoretically in a blank determination the whole of the iodine should be found on titration, and the solution should contain no free acid, but in practice this is never the case, for the older the solution the less the iodine titre and the greater the acidity, the deficiency in iodine being equivalent to the acid formed. The author explains the alteration which occurs in the solution on keeping by the fact that hypoiodous acid oxidizes the alcohol to aldehyde. and that this causes a disturbance in the equivalence of the solution.Ordinarily each molecule of hypoiodous acid gives on titration (4) two atoms of iodine, but when there is aldehyde formation only one atom is liberated and the titre is correspondingly smaller. On the other hand, for each molecule of hypoiodous acid reduced a molecule 2HIO + C,H,O = 21 + H20 + C,H,O ;THE ANALYST. 239 of hydrochloric acid is set free, which is not neutralized as in equation (4), and which therefore leaves the liquid acid. This hydrochloric acid the author terms ‘‘ excess acid.’’ The stability of Hiibl’s solution may therefore be increased by keeping the concentration of hypoiodous acid as low as possible, as in Welman’s method, in which alcohol is entirely or for the most part replaced by ether, ethyl acetate or anhydrous acetic acid.Waller (ANALYST, xx., 280) obtained the best results by adding strong hydrochloric acid, which acts not by combining with the water present, but by favouring the formation of iodine chloride and preventing its decomposition as in equation (2) Of the substances taking part in the actual addition, free iodine is so slowly absorbed that it need not be taken into account in explaining the reaction. Like Ephraim (Zoc. cit.) the author formerly regarded iodine chloride as the chief agent in the addition, but has now come to the conclusion that the hypoiodous acid must be regarded as the principal substance. He argues that if iodine chloride were the most important, Waller’s solution, which contains more iodine chloride, would act more rapidly than Hiibl’s solution, whereas experiments have shown the contrary to be the case.On the other hand, by shaking an alcoholic solution of iodine with finely divided mercuric oxide and filtering, the filtrate, according to Koene (Pogg. Ann., lxvi., 302), contains mercuric iodide and hypoiodous acid, and with this solution correct iodine values were very rapidly obtained. A number of determinations of the iodine value of earthnut-oil, by means of Hiibl’s solution, to which various substances had been added, showed that when these substances favoured the formation of hypoiodous acid (e.g. iodine, mercuric chloride, and water), the halogen absorption took place more rapidly, whilst the converse was the case with substances which tended to repress its formation, such as hydrochloric acid and mercuric iodide.In determinations of the iodine value there is invariably an increase in the excess acid.” The author considers that besides the addition of halogen, there is a further reaction with hydrochloric acid which, in the case of oleic acid, may be expressed thus : C0,H.C17H,I*OH + HCI = C0,H.C17H3,1CI + H,O. But this only occurs without further change in strongly acid solutions like that of Waller. With solutions containing less acid there is a considerable increase in the ‘( excess acid,” which is to be accounted for by a splitting off of hydrochloric acid. C0,H~C17H3,1Cl = C02H.C17H,,I + HCI. The conclusions which the author has formed on this point are : 1.The separated acid is, ceterisparibz6s, proportional to the amount of absorption. 2. Under the same conditions different fats all yield about the same quantity of But with substances of a different 3. The greater the acidity of the solution, the smaller the quantity of acid acid, proportional to the amount of fat taken. constitution (ally1 alcohol, cholesterol) different figures are obtained. separated.240 THE ANALYST. 4. The separation is most thorough in liquids which most readily dissolve hydro- Thus it is greater in alcohol containing water than in chloroform, and I n conclusion, the author summarizes the principal reactions which occur in the 1. In the preparation : chloric acid. in methyl alcohol than in ethyl alcohol. Hubl process in the following equations : HgC1, + 41 = HgI, + 21Cl ICl+ H,O = HC1+ HLO.2. On keeping the solution : 2HIO + C,H,,O = 21 + H,O + C,H,O. 3. I n the absorption (oleic acid) : CO,H.C,;H,, + HI0 = CO,H~C,;H,,I*OH. CO,H.C,;H,,I.OH + HC1= CO,H.C,;H,,ICl+ H20. &4nd in a part of the fat : CO,H.Cl7H3,IC1 = C0,H.C,7H,,I + HCl. C. 8. M. A New Method o f Determining the Iodine Absorption of Oils. J. J. A. Wijs, (Bericlzte, 1898, xxxi. [6], 750-752.)-1n a former paper (ANALYST, preceding abstract} the author gave his reasons for concluding that in the Hub1 process the substance chiefly concerned in the addition is hypoiodous acid, and he now suggests the more direct application of this acid as a means of improving the process. The fact, however, that it so readily decomposes (5HIO = HIO, + 2H,O + 41) prevents it being employed with any advantage at first hand.I t was therefore found best to obtain the acid by the action of water on iodine chloride (IC1 + H,O = HCl + HIO), choosing a solvent which only contained so much of the former as would decompose nearly the whole of the latter, and which at the same time would not be oxidized by the hypoiodous acid. Good results were obtained with a solution of iodine chloride iu 95 per cent. acetic acid. This was prepared by dissolving 13 grammes of iodine in a litre of the acetic acid, determining the (‘halogen content ” of the solution and passing in a current of chlorine (free from hydrochloric acid) until the ((halogen content” was doubled. With a little practice this point was readily hit by the change in colour.The solution thus prepared was more stable than that of Waller (AKALTST, xx., 280), and was employed precisely in the same way as Hubl’s solution, with the exception that the length of time required for the absorption was very greatly reduced. I n the case of oils with low iodine values, it was complete in three or four minutes, and with those with higher values not more than ten minutes was necessary, if too much oil had not been taken. The following table gives the results obtained with this solution, compared with those of the ordinary Hubl process :THE ANALYST. I. Value. 11 oil. I 241 Excess of Iodine. Per cent. Excess of Iodine. Per cent. 182.25 182.17 Time of Absorp- tion. I 57 17 9 ) 124.87 (Hiib1)ll- I Time of Absorp- tion. I Oil.I. 1 7 ~ i u ~ . Linseed 68 57 57 57 4 hours 5 min. 7 1 , 10 9 1 4 hours 5 min. 110.35 (Hubl) 111.87 111.75 108.76 (Hiibl) 110.07 109.83 Liver-oil 61 47 52 65 62 4 hours 5 min. 7 9 , 8 1 , 9 9 1 102.96 (Hiibl) 103-08 103.33 4 hours 3 min. 7 1 7 Maize ... 68 65 64 64 4 hours 3 min. 6 1 , 7 9 , 74 70 70 70 87.26 (Hubl) 86.89 87.13 87-25 127-55 ' 128.56 128.38 4 hours 2 min. 3 ) ) 7 9 , 4 hours 3 min. 7 1 , Poppy ... 69 69 57 4 hours 119*36(Hiibl)! - 3 min. ~ 119.66 Olive 7 ,, 119-67 70 70 70 83.27(HUblj 84.39 84-45 Sun- flower 70 69 63 In almost every case,the values given by the new solution were higher than the ordinary Hub1 values, but the author considered them the more correct by reason of the results obtained with purified ally1 alcohol. This has a theoretical iodine value of 435.By Hiibl's process Lewkowitsch obtained values varying from 349 to 376. Using an excess of 75 per cent. of iodine, the author found it to have an iodine value of 425 by Hiibl's process, whilst with iodine chloride in acetic acid (the excess of iodine being the same) his results were: after five minutes 434.1 and after ten minutes 436.8. C. A. M. Candle-Nu.t Oil. G. de Negri. (Oesterr. Chem. Zeit.," 1898, i., 202.)-The following particulars respecting this substance were derived from the examination of two small samples extracted from seeds by the author himself : one with ether, the other with petroleum spirit. The yield was 62-25 per cent. ; the product a bright, transparent, pale-yellow oil, which soon became rancid, and dried only a little more readily than tung-oil. I t was soluble in ether, petroleum spirit, and chloroform; insoluble in cold absolute alcohol, with which it yielded a turbid mixture, but slightly soluble in hot alcohol.I t did not dissolve in (? cold) glacial acetic acid ; a t the boiling-point it was soluble in equal volumes. It remained liquid at a temperature suchung, Hygiene, und Warenkunde ; ancl the corresponding reference is 1898. xii. [14], 202. * This is the same journal that was formerly known as the Zeitschrift fur Nahrnngsmittel-Unter-242 THE ANALYST. of - 18" C. I t was readily saponified by alcoholic alkali, the soap being easily soluble in water. Some of the constants are given herewith : Extracted with Extracted with Ether. Petroleum Spirit. ... ...... ... 0.920 Specific gravity at 15" 0.926 Saponification number ... ... ... ... 187.36 184-0 Iodine number ... ... 139.34 136.29 Melting-point of fatty acids ... ... 20-21" Solidification point of fatty acids.. . . . . ... 13" Iodine number of fatty acids ... ... . . . 144.13 142.71 ... ... - ... - Refractometer number at 15" (Zeiss-Wollny) ... - 76-75.5 With BrullA's test it gave no colour in the cold ; on warming, a red which was permanent for twenty-four hours, while the oil became thick. Baudoin's test pro- duced no colour. With Becchi's test the oil extracted by light petroleum yielded an intense brown; that recovered with ether only a faint brown. When exposed to the direct rays of the sun in sealed tubes for twenty-five days, both specimens of candle-nut oil, and also extracted tung-oil, remained perfectly liquid ; whereas expressed tung-oil polymerized and formed some solid matter.Candle-nut oil recovered by carbon disulphide remained fluid when treated as above ; tung-oil obtained by the same solvent solidified. The material described by Laach (Chenz. Zeit., 1890, 871) was probably a mixture of fatty acids from different kinds of alezwites, for his figures are very unlike those observed by De Negri. F. H. L. Improvements in Organic Combustion. F. Swarts. (Chem. Zeit., 1898, xxii., 474.)-This process was originally devised for the ultimate analysis of com- pounds containing fluorine, but it is equally well adapted for all classes of organic bodies. I n place of the ordinary glass tube, a seamless tube of copper is employed, about 1-5 metre long, 12 to 18 mm. in diameter inside, with walls 3 or 4 mm.thick. I t is first cleaned by being ignited in a furnace while a current of air is passing through it ; by which means also a coating of oxide is formed that materially assists in the combustion. In order to protect the corks at either end from being injured by the excessive heat due to the high conductivity of the metal, short jackets (about 12 to 15 cm. x 3 to 4 cm. in size) with corks and leading tubes are applied close to both extremities, and water is kept circulating through them. The com- bustion tube is charged much in the usual fashion; but instead of using copper oxide alone the author prefers a mixture of three parts of CuO with one of granulated PbO, the latter prepared by heating pure red lead to incipient fusion in a copper basin with constant stirring.The tube is laid in a Glaser furnace; the substance to be burnt in a boat. At the point where the boat stands, the bent iron bottom-plate of the furnace is removed, and its place is taken by a, somewhat more deeply curved casting having a hole and leading tube at its lowest point. Immediately over the tube at the same spot is a short piece of copper pipe closed at each end, perforated underneath with many fine holes, and connected to a water-supply. By the aid ofTHE ANALYST. 243 a tap a stream of water (which afterwards runs away through the hole just men- tioned) may be caused to play on the portion of the main combustion tube that surrounds the boat ; and, by regulating or stopping the supply, the substance can be volatilized in the current of purified air at any desired speed.I n this manner much time is saved, for the copper-lead oxide can be brought to a red heat while the weighings are in progress, and the organic body maintained cold when in position until the roll of oxidized copper gauze at the other end of the tube is also hot. When the combustion seems to be nearly finished, the rubber tubes for the delivery and exit of the water are disconnected, and the part of the copper tube round the boat is brought to a red heat for five or ten minutes in order to burn up the residual carbon. Some of the water from the oxidation of the material is condensed at the end of the tube by reason of the short condenser there fixed.This may be driven over into the absorbing vessel by stopping the current of water, emptying the jacket if necessary till the deposited moisture boils again ; but the amount retained within the tube may be reduced to a minimum by so regulating the current that the extreme ends of the copper are kept slightly warm all through the operation. Not only can the copper tube be raised to the working temperature almost instantaneously, but the speed of the combustion itself is under ready control. Com- pared with these advautages, the lack of transparency is not a serious obstacle, for the progress of the operation can be gathered by watching the potash bulbs. The coating of copper oxide in the tube prevents the deposition of very resistant carbon ; and the tube itself lasts for about sixty analyses before being worn out.F. H. 11. Kjeldahl’s Method and its Modifications. A. Atterberg. (Chenz. Zed., 1898, xxii., 505.)-Reviewing seven different modifications of the original Kjeldahl process in a recent work on chemistry, the author stated that Kellner’s seemed to be the best and quickest. The matter has now been further investigated, using as a test- substance a bog-earth containing 15 per cent. of moisture and 7 per cent. of ash, and conducting the oxidation as fast as possible in a, 250 C.C. flask. Gunning’s method occupies ninety-five minutes, and much frothing occurs; if a drop of mercury is added, the time is roughly halved ; if the potassium sulphate is not introduced till the material is dissolved (the proportion between the H2S0, and the K2S0, being kept as specified by Gunning), the process only takes about twenty-six minutes, and no foaming is noticed.Kellner’s method requires forty-five minutes, which may bs reduced to twenty-seven by the employment of potassium sulphate. The latter substance therefore is just as efficient as Kellner’s phosphoric anhydride-both raise the boiling-point of the sulphuric acid; and orthophosphoric acid itfielf might be used instead of the anhydride were it not for the separation of mercury phosphate, which interferes with the boiling of the liquid. Experiments have been tried with metals or oxides other than mercury, in order, if possible, to avoid the necessity for adding sulphide when distilling off the ammonia. Only molybdic acid ( c j .ANALYST, xxi., 267) has been found to work without frothing; but as the oxidation is made a trifle slower, the final solution is blue instead of colorless, and commercial speci- mens of the reagent often contain much nitrogen, it can hardly replace mercury.244 THE ANALYST. The author quotes some figures obtained with sulphate of quinine which go to prove that the best oxidizing solution is composed of 20 C.C. of strong sulphuric acid, 15 to 18 grainmes of potassium sulphate, and a little mercury. When frothing is expected, the sulphate should not be introduced till the nitrogenous body is dissolved, otherwise it may be added at the outset. Decolorization takes place (in a 250 C.C. flask) in about 30 minutes ; but the whole should be boiled 15 minutes longer.F. H. L. Detection of Sulphur and of Nitrogen in Organic Bodies by means of Phloroglucinol and Vanillin. (Chent. Zeit., 1898, xxii., 377.)- The red colour which is produced in a dried alcoholic solution of phloroglucinol and vanillin by the action of the halogens has already been described (ANALYST, xxiii, 99). A similar reaction is determined by sulphur, phosphorus, and arsenic ; and in the case of sulphur it is so general that the test is available for the examination of organic substances of whatever kind. I t shows the presence of thiophen in benzene, and it dis- tinguishes between the proportion of the impurity in German, Russian, and Pennsyl- vanian petroleum. Sulphuretted hydrogen does not yield the red colour ; it is derived from sulphurous oxide, and the test is so delicate that if methyl thiocyanate is diluted with alcohol, and a drop equivalent to 0*001 milligramme of sulphur is burnt, the coloration is still visible.As Becchi’s test for cotton-oil depends on the sulphur it contains, experiments have been made (and are still unfinished) on various oils with the present reagent. Sesamb, castor, walnut, olive, arachis, white cod-liver, and huile de Veillette, give no colour. The colour produced by linseed-oil is much fainter than that of colza or cotton-oil, and the degree of volatility of the compound which contains the sulphur varies largely in different oils, that in cotton-oil having such a high volatilizing point that the strength of the reaction is not diminished when the oil is treated with steam for twelve hours.All of these oils contain but little sulphur, and as many burn with a very smoky flame, the test is rather diflicult to carry out. The sample is best burnt in a glass tube bent at a right angle close to the end; in the bend is placed some long fibre asbestos to act as a wick, and the size of the flame is regulated by altering the posi- tion of the tube. If the flame be kept quite small and held very near the lid of the porcelain crucible which bears the dried film of reagent, the colour soon appears ; but if the soot is still troublesome the oil may be diluted with ether or alcohol. All kinds of albumin, fibrin and casein give a fine red colour, as do also all varieties of paper, even filter-paper. The behaviour of nitrogenous organic matter with the mixture of phloroglucinol and vanillin depends on whether the compounds evolve their nitrogen as acid, ammonia, or in the free state, when they are broken up.If a few drops of the reagent are mixed with one drop of nitric acid, and the whole set light to, an intense red colour is produced ; under similar conditions ammonia gives a bright yellow. No colour at all is formed when any nitrogenous substance is held in a loop of platinum- wire in a powerful Bunsen flame under the porcelain lid, because the nitrogen is set P. N. Raikow. Cotton, colza, linseed, rape, and seal, yield a more or less intense red.THE ANALYST. 245 free. No colour is produced if nitro- or nitroso-compounds or nitriles are allowed to burn by themselves; but amines and similar bodies give a yellow.Aromatic com- pounds in which the nitrogen is part of the closed chain as a rule give no yellow, q., quinoline, piperidine, etc., but antipyrin and isatin yield faint yellows. The test will show 1 per cent. of aniline in quinoline. When nitrogenous bodies which give the yellow reaction also contain sulphur or a halogen, the red colour is produced as well, e.g., thiourea, chloraniline, methyl violet, etc., also wool, hair, feathers, casein. But sometimes a faint red is to be found even in the absence of sulphur and chlorine, as part of the nitrogen has burnt to acid ; in this case the sample should be decomposed in the Bunsen flame, when no red will be observed. Raikow prefers to dissolve the phloroglucinol and vanillin in ether rather in alcohol, as the solution is more permanent, and also to use it much weaker recommended by Giinzburg.F. H. than than L. Remarks on the Estimation of Tannin, and on the Titration of Tannin and Gallic Acids. F. Jean. ( A m . Chim.. Analyt., vol. iii. [5], pp. 145-149.)-The author confirms the observation made by Raii (Jour. Amer. Chem. SOC., vol. ix., No. 4), that LIP to 50 per cent. of gallic acid is fixed by hide powder and other gelatin-yielding tissues, and also demonstrates that, in order to more closely approximate laboratory r-esults to those obtained in tannery practice, the Hammer method requires modifi- cation to render it suitable for the estimation of tannin and substances which can be fixed by the hide. With this object he proposed to replace the treatment with hide powder by forty-eight hours' maceration with finely-shredded rabbit-skin - the anatomical structure of which has not been destroyed-since he finds that by this ineans the fixation of gallic acid is reduced from 42 per cent. to 27 per cent. Similarly, the Hammer method is unsuitable for determining the tannin and gallic acid in astringent bodies, such as sumach. I n this case, albumin proves the best means of separating these two substances, a sumach that yielded 2.396 per cent. of gallic acid when treated with hide powder furnishing 13.4 per cent. of the acid by the albumin method. The loss of gallic acid observed when working with a mixture of known composition is reduced by this latter method to 2.2 per cent. c. s. Method of Preparing Pure Sugar. H. Pellet. (Bull. Assoc. Chim. de Sucr. et Distill., vol. xv., p. 813 ; through Rev. Chim. Aizalyt. Appl., vol. vi. [9], p. 143.)- Five hundred grammes of refined loaf-sugar are dissolved in 250 grammes of distilled water and filtered if necessary. To the clear solution 560 to 570 C.C. of absolute alcohol are added by degrees, the liquid being agitated to prevent crystallization, and afterwards covered up and set aside for several days to allow the excess of sugar to crystallize out. The supernatant liquid is then poured off, and the crystals-which are loosened from the walls of the vessel by immersing the latter in warm water- are collected in a tapped funnel, and washed with alcohol increasing in strength from '70 per cent. to 100 per cent. Finally, they are dried over sulphuric acid, and a246 THE ANALYST 10-gramme sample is incinerated to test the freedom from ash. If found impure, the crystallization process is repeated. c. s.

ISSN:0003-2654    

DOI:10.1039/AN8982300234

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

246 THE ANALYST I N 0 RGAN I C ANALYSIS. The Separation of Mercury and Bismuth. L. Vanino ani I?. Treubert. (Beg.., 1898, xxxi., 129, 130.)-This is based on the fact that on adding to a dilute hydrochloric acid solution of mercuric chloride and bismuth oxychloride a mixture of hypophosphorous acid and hydrogen peroxide (1 drop of the former to 1 C.C. of the latter), the mercury is separated quantitatively as calomel, while the bismuth remains in solution, and can be precipitated by the further addition of hypophosphorous acid. The details of the method are as follow : The solution of the mixed salts is treated with the reagent as above, and, after standing for about an hour, the precipitated calomel is filtered off, rapidly washed free from bismuth, first with dilute hydrochloric acid, and subsequently with cold water, and dried at 105" C.The filtrate is made slightly alkaline with sodium hydroxide, warmed over a naked flame, and hypophosphorous acid added until no more black precipitate is produced, and no turbidity occurs in the supernatant liquid on the addition of water. The pre- cipitate is pressed into a compact mass with a glass rod to prevent oxidation during the drying, collected on a Gooch's filter, washed successively with water and alcohol, and dried at 105" C. A table giving the results of the method applied to a test mixture shows that the figures obtained in this way are in close agreement with those required by theory. C. A. M. Qualitative Separation of the Metals of the Iron, Chromium, otc., Group, and of the Rare Earths. (Giowz.diFarm. di Trieste, 1898, iii., 70; through Chenz. &it. Rep., 1898, 135.)-The original solution is treated with ammonia and ammonium sulphide, and separated into a filtrate (A) and a precipitate (B) containing the hydrates of Fe, Cr, Al, Ce, La, Th, Zr, Y, U, Be, Di, the sulphides of Mn, In, Ni, Co, and the phosphates, etc., of Ba, Sr, Ca, and Mg. This is warmed with 1 : 5 HCI, which dissolves everything except the Ni and Co. The solution (C) is mixed with nitric acid, boiled for a time, then cooled, and made just alkaline with strong KHO. Only the Be is left unprecipitated, and it is thrown down on diluting the liquid with three or four times its volume of water and then boiling. The precipitate (D) is boiled in KHO to remove A1 and Zn, and the insoluble matter (E) is washed and digested in amnionium carbonate solution with occasional agitation for twelve hours, The filtrate (F) contains the carbonates of Ce, Th, Zr, La, U, Di, and Y ; the residue (G) Mn, Fe, Cr, and Ba, Sr, Ca, Mg as phosphates, borrttef3, etc.After the Mn, Fe, and Cr have been specially tested for in small quantities of (G), the main portion is boiled for ten minutes with sodium carbonate solution, which decomposes the bulk of the phosphates, etc., of the alkaline earths into carbonates, giving a solution (H) and a precipitate (L). The latter is dissolved in HCX, precipitated with ammonia and G. Posetto.THE ANALYST. 247 sulphide, the insoluble portion is thrown aside, and the filtrate, mixed with the first solution (A), is examined for alkaline earths and alkalies as usual.(3') is boiled till the carbonates are deposited and the liquid yields no residue on evaporation. The precipitate (N) is divided into different parts : (1) Is mixed with hydrogen peroxide-in presence of Ce the white powder changes to yellow-or it is boiled with excess of nitric acid and lead peroxide, when the liquid becomes yellow. (2) I s treated in a porcelain basin with a few crystals of iodine-La causes the mass to turn blue. ( 3 ) Is dissolved in water containing a trace of HC1 and subdivided into three, Turmeric paper is dipped into (3a) and dried at 100" C.-a red colour like that produced by boric acid indicates Zr. ( 3 b ) Is tested with potassium ferro- cyanide-U gives a red colour or precipitate.(3c) Is treated with sodium carbonate -Di forms a white precipitate insoluble in excess, A fourth portion of (N) is dissolved in weak HC1, neutralized with KHO, a few crystals of normal potassium sulphate added, and the whole boiled. Th, Zr, and Ce are thrown down as double sulphates (0). The filtrate is again boiled several times to ensure the removal of all insoluble matter ; but Y remains in solution, and may finally be recovered on addition of ammonia. The precipitate (0) is boiled in HCl and water-the double sulphates of Th and Ce dissolve, that of Zr remains unattacked. The solution is treated with oxalic acid to throw down the earths, and the Precipitate is boiled in strong ammonium oxalate till it dissolves. After cooling, the liquid is diluted with three times its volume of water, which deposits the oxalate of Ce.The Th is recovered from the filtrate by treatment with ammonia. F. H. L. Precipitation of Platinum from its Solutions. A. Atterberg. (Chem. zed., 1898, xxii., 538.)-Of the numerous substances which may be employed to throw down metallic platinum from its solutions, thiacetic acid, mercury, and magnesium are the most useful, The first yields a particularly voluminous precipitate, and it is therefore to be recommended when only traces of the metal have to be dealt with. When it is desired to estimate the sodium in the alcoholic filtrate from a potash determination mercury is the best reagent. The platinum solution is concentrated to 8 small volume on the water-bath in a deep porcelain basin, an excess of mercury is added, and the whole is well stirred till the reaction is complete.The by-product is mercuric (not mercurous) chloride, and can easily be removed by heat. The reduction only takes place in the warm; the platinum is deposited as a compact powder, but the operation must never be conducted in a platinum vessel, as the metal sticks firmly to the walls, If the platinum which is in solution has to be weighed, the best precipitant is magnesium ribbon. The liquid may be neutral, but it is better acidified with a little hydrochloric acid. The deposition proceeds slowly in the cold, more quickly on warming or on agitation ; but a trace of metal remains in solution for some time, giving it a grayish colour, so that the liquid should not be filtered until it is water-white.The platinum is heated with HCl, washed very thoroughly, and gently ignited. For working up alcoholic platinum residues magnesium ribbon is aIso most248 THE ANALYST. convenient. off, purified with acid, and washed. In twenty-four hours all the metal is thrown down, and can be decanted F. H. L. Separation of Nickel and Cobalt with Potassium Nitrite. Schlagdenhauffen and Fageot. (Bull. C O ? ~ L C ~ * C . , 1898, xxvi., 225 ; through Chenz. Zeit. Rep., 189S, 170.)-When describing this process, the books usually require that the solution of the metals shall be treated with an equal volume of nitrite and an exces? of acetic acid. The present authors find that this is not sufficiently explicit to ensure uniform results. The strongly concentrated liquid containing the metallic chlorides must be mixed with a cold-saturated solution of potassium nitrite, diluted with at least fiye times its volume of water, and 15 to 30 C.C.of acetic acid added for every 1 gramme of chloride present. The nickel remains in solution and the cobalt is completely precipitated, so that the method serves for their quantitative separation, or for the tletection of traces of either one in the other. F. H. L. The Colorimetric Estimation of Small Amounts of Chromium. W. F. Hillebrand. (Jow. Amc~. ClLcnz. SOC., 1898, xx., 454-460.)-The chromium is brought into solution as monochromate, the liquid rendered alkaline with sodium carbonate, and compared with a standard solution of chromate, also made alkaline with sodium carbonate. Two standards are prepared, containing 0.25525 and 0.5105 gramine of potassium chromate per litre respectively, a little sodium carbonate being added to each.One C.C. of the first solution corresponds to one-tenth of a milli- gramme of chromium oxide. I n testing the applicability of the method to the determination of chromium in rocks and ores, varying amounts of the standard solution were evaporated in a crucible with 5 granimes of an iron ore containing phosphorus and vanadium, and the residue fused with 20 grammes of sodium carbonate and 3 grammes of sodium nitrate. The aqueous extract was nearly neutralized with nitric acid after the reduction of the manganese with alcohol, and was evaporated so as to approximately separate the silica and alumina. I n order to recover any chroiniuin carried down with these, the precipitate was ignited, the silica removed by treatment with sulphuric and hydrofluoric acids, the residue fused with sodium carbonate, the alumina separated as before, and the filtrate added to the first filtrate.Mercurous nitrate was then added, and the resulting precipitate, containing phosphate, chromate, vanadate, and carbonate of mercury, was slightly washed and ignited. The residue was fused with sodium carbonate, extracted with water, filtered, the solution made up to 50 or 100 C.C. and the colour compared with'the standard, as in a Nessler determination of ammonia. A similar determination was made with a silicate rock. Chromic Oxide added. Chromic Oxide found. Milligrammes. Milligramines. 1. Five grammes iron ore .. . 7.03 7.18; 7.20; 7.25; 7.21 3. Two grarnmes silicate ... 1.6 1.53; 1.57 ; 1.59 2. Y , ), ... 2.99 3.08; 3.13THE ANALYST. 249 When the percentage of chromic oxide in an ore exceeds two-tenths per cent., and a vanadium determination is not required, the colour of the original extract of the carbonate fusion may be matched after reduction and removal of the manganese, but when much less than that quanfity is present the precipitation with inercurous nitrate is necessary to obtain a sufficiently colored filtrate in a small bulk. c. A. ni. The Volumetric Determination of Vanadium in the Presence of Small Amounts of Chromium. W. F. Hillebrand. (Jow. Amer. Chew. Soc., 1898, xx., 461-465.)--When chromium and vanadium occur together, and the former has been estimated colorimetrically (see preceding abstract), the vanadium can in man>- cases be determined without separation from chromium by reduction with sulphurous acid and titration with permanganate in sulphuric acid solution.The one limitation to the method is that too much chromium must not be present, since it interferes with the end-reaction ; but satisfactory determinations of as little as 1 or 2 milligrammes of vanadium pentoxide can be made in the presence of 30 milligrammes of chromic oxide. The method is not applicable in the presence of molybdenum, and arsenic, if present, must be removed by precipitation with sulphuretted hydrogen. The rock or ore (free from arsenic) is fused with sodium carbonate and nitrate, the melt extracted with water, the manganese reduced, the silica and alumina removed, and the chromium determined colorinietrically, as described in the preced- ing abstract.After the colorimetric determination, sulphuric acid is added, the chromiuin and vanadium reduced by means of sulphur dioxide, and the excess of the latter expelled by boiling the liquid in a rapid current of carbon dioxide. When cooled to about 70" or 80" C., the solution is titrated with a very dilute standard solution of potas- sium permanganate, of which 1 C.C. corresponds to about 0.001 gramme of vanadium pentoxide as calculated from its equivalent in iron. The subjoined table gives the results of test analyses of an iron ore and silicate rock to which known amounts of chromium and vanadium had been added : Chromic Oxide Vanadium Pentoxide added.added. Milligrammes Milligrammes. Iron ore, 5 grammcs . . . 7 6-76 Silicate, 2 grammes ... 1-6 1-87 9 9 $ 9 ... 3 3 Vanadium Pentoxide found. Milligrammes. 6.81; 6.48; 6.43; 6.37 3.08; 3.13; 3.03 1.86; 1-97; 2.07; 1-86 C. A. M. The Iodometric Estimation of Tellurium. J. F. (Awzer. Chem. Jour., 1898, xx., 278-283.)-Attempts were Norris and H. Fay. made to employ the volumetric method found satisfactory in the case of selenium (ANALYST, xxii., p. 82) in the estimation of tellurium. One molecule of tellurous acid reacts with four of sodium thiosulphate in the presence of dilute acid, but the end-point is not sharp, since the addition of the thiosulphate produces EL yellow solution, and the reduced tellurium compound is slowly oxidized by iodine.A more successful method mas found in the oxidation of tellurous acid to250 THE ANALYST. telluric acid by means of potassium permanganate, and determination of the excess of the latter by adding potassium iodide and sulphuric acid, and titrating the liberated iodine with thiosulphate. The reactions involved in the process are : (1) 2KMn0, + 3Te0, = K20 + 2Mn0, + 3Te03, in which the manganese is not precipitated, but remains in solution probably as a manganite or in combination with the telluric acid. On adding to such a solution potassium iodide and sulphuric acid, the following change occurs : (2) 2Mn02 + 4KI + 4H,SO, = 2MnS0, + 2K,S04 + 4H,O + 41. (3) 2KMn0, + lOKI + 8H,SO, = 2MnS0, + 6K2S0, + 8H,O + 101. Any excess of permanganate reacts thus : Combining equations (1) and (2), the oxidation of tellurium dioxide may be thus expressed : (4) QKMnO, + 3Te0, + 4KI + 5H,S04 = 3TeO3 + 3K2S0, + 2MnS0, + 5H,O + 41.The precautions to be observed are that the oxidation must take place in the presence of a large excess of alkali, and that the solution must be dilute and cold in order to prevent the reduction of the telluric acid by the hydriodic acid. A sample of pure tellurium dioxide analyzed in this way gave eight results varying from 79.80 to 80-15 per cent. of tellurium, as against 79.94 per cent., the theoretical amount, The accuracy of the method in the presence of halogen acids was proved by the analysis of the double bromide of tellurium and potassium with which four consecutive results (18.58 to 18.64 per cent.) were obtained, the theoreti- cal percentage of tellurium being 18.61.Experiments proved that this method is also applicable to the determination of selenium, but it offers no advantages over the simpler method proposed before. c. A. &I. Estimation of Various Sulphides by Titration with Permanganate. J. Hanus. (Zeits. c~norq. CJzem., 1898, xvii., 111.)-The sulphides of antimony, lead, and bismuth are oxidized by treatment with ferric sulphate, and the reduced ferrous salt can be titrated with permanganate in the usual way. Tin and cadmium behave similarly, as mentioned by Mohr ; but the reaction with copper is not complete, and the sulphides of mercury and arsenic cannot be determined in this manner. About 0.2 or 0.3 gramme of precipitated antimony trisulphide is washed into a beaker and boiled for 15 minutes with excess of powdered ferric sulphate ; after cooling, sufficient strong sulphuric acid (15 c.c.) is added to dissolve the precipitate, and when this is effected the clear liquid is made up to 200 c.c., filtered through a dry filter, and 100 C.C.taken for titration with the permanganate. Free sulphur does not affect the process ; but the precipitate must be entirely dissolved in the sulphuric acid, and it must not be exposed to air, or some inert red oxysulphide may be produced. The reaction is as follows : Sb,S, + 5Fe,(SO,), + 8H20 = 2H,SbO, + 10FeS0, + 5H,SO, + S,.THE ANALYST. 251 With lead the process works satisfactorily, provided not more than 0.3 gramme of PbS is taken. Two molecules of ferrous sulphate result from the oxidation of one of lead sulphide. In the case of bismuth sulphide, which is attacked with great ease, the proportion is Bi,S, = GFeSO,. F. H. L. Solubility of the Bicarbonates of Calcium and Magnesium. and M. Reuter. (Zeits; nizory. Chenz., 1898, xvii., 170.)-This an account of various experiments on the bicarbonates of the F. P. Treadwell article contains alkaline earths which were carried out to determine whether these compounds actually exist as such, and also to estimate their solubility in water in the presence or absence of free carbon dioxide. The results given briefly are : Calcium bicarbonate does exist as such in aqueous solution, its solubility at 15" C. and average atmospheric pressure being 0.385 gramme per litre. The solubility of calcium bicarbonate is not appre- ciably affected by dilute (decinormal) solutions of common salt. Magnesium bicar- bonate does not exist in solution except in the presence of free carbon dioxide; in the absence of the gas it breaks up into a mixture of normal carbonate and bicarbonate, until the liquid, at the above temperature and pressure, contains 0.715G graniiiie of the former and 1.954 gramme of the latter per litre. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN8982300246

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

THE ANALYST. 251 APPARATUS. An Apparatus for the Analysis of Calcium Carbide. H. Bamberger. (Zeit. angew. Chem., 1898, 243.)-This is recommended for the simple aud accurate valua- tion of calcium carbide by a method combining the author’s graviinetric process (ANALYST, this vol., p. 167) with the gas-volumetric process of Fuchs and Schiff (ANALYST, this vol., p. 25). The flask A, which serves a s 8 gasometer, c o n t a i n s 20 litres, and is graduated into decilitres. It is connected with a similar flask, B, and is nearly filled with a concentrated solu- tion of sodium chloride, satu- rated with acetylene at the ordinary temperature. The gas is generated in the gravimetric flask, C, and drives the brine forward into 13. When the reaction is over, the liquids in both flasks are brought to the same level, and the amount of acetylene read off and corrected for temperature and pressure (cf.ANALYST, this vol., p. 25). The apparatus can be obtained from Max Kiihler and Martini, Berlin, W. c. A. M.352 THE ANALYST Apparatus for the Delivery of Small Quantities of Mercury (for Nitrogen Determinations). R. Meyer. (Chem. Zeit., 1898, xxii., 331).-As shown in the accom- panying illustration, this apparatus serves for the storage of about 250 grammes of mercury in the bulb a, and also for the delivery of a definite amount of the reagent such as is required in a Kjeldahl nitrogen estimation. When the hemispherical depression in the stopcock o is in a vertical position it fills with mercury from the reservoir, and when it is rotated till opposite the exit tube d the mercury runs out, its place being taken by air entering through e and the groove in the cock.e also catches any drops that may escape out of the groove while the hole is being filled. F. H. L. An Improved Analytical Balance. (Chew&. Zed., 1898, xxii., 540.)-This apparatus consists essentially of a short-beam analytical balance, which, in order to gain an approximate idea of the weight of any substance placed in the pan, can be tem- porarily put in con- nection with a spring- balance by means of the knob seen project- ing from the top of the case in the accompany- ing illustration. When the spring-balance is in gear, the long lever shows the weight of the substance on the curve scale t o t h e nearest deci- or centi- gramme; end, after it has been thrown out, the correct weights can usually be placed at once on the opposite pan, leaving only the rider of the balance proper to be manipulated. The convenience of this arrangement is apparent, and it will be specially appreciated in weighing out exact quantities of things, for during the whole process the arresting-gear of the true balance need not be used at all (see also ANALYST, xxi., 248). F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN8982300251

出版商:RSC    

年代:1898

数据来源: RSC