摘要:

THE “ SOCIETY OF PUBLIC ANALYSTS.” PUBLISHED XONTHLY. Organization amongst Chemists . 19 On the Determination of Quinine. By i. H: Allen, F.C.S. , . , , . . 19 Discussion on ditto . . . . . 23 25 Persian Opium, By W. D. Howard . . 25 The Detect.ion of Colouring Matters in Wine. By A. DuprB, Ph.D., F.K S. . . . 26 Accuracy in Dispensing , . . . 27 LiquorAmmonae Acetatis. By J. Thresh) F.C.S. Potassium Iodide.By F. F. Best, F.C.S. . 27 The Preparation of Dextrine-Maltose. By W. G. Valentin, F.C.S. . . . . 28 Prosecutions under the Sale of Food and Drugs Act . . . . . . . 3 3 Note on the Estimation of the Gravities of Fats. By G. W. Wigner, F.C.S. . . 35 Meeting of the Society of Public Analysts . 35 Paragraphs . , . . . . 35 A. H. ALLEN, F.C.S. J. FALCONER KING. A.WYNTEB BLYTH, N.R.C.S. R. H. HARLAND. C. A. CANERON, M.D. E. W. T. JONES, F.C.S. C. H. PIESSE, F;C.S. F. J. LLOYD, F.C.S.THE “ SOCIETY OF PUBLIC ANALYSTS.” PUBLISHED XONTHLY. Organization amongst Chemists . 19 On the Determination of Quinine. By i. H: Allen, F.C.S. , . , , . . 19 Discussion on ditto . . . . . 23 25 Persian Opium, By W. D. Howard . . 25 The Detect.ion of Colouring Matters in Wine.By A. DuprB, Ph.D., F.K S. . . . 26 Accuracy in Dispensing , . . . 27 LiquorAmmonae Acetatis. By J. Thresh) F.C.S. Potassium Iodide. By F. F. Best, F.C.S. . 27 The Preparation of Dextrine-Maltose. By W. G. Valentin, F.C.S. . . . . 28 Prosecutions under the Sale of Food and Drugs Act . . . . . . . 3 3 Note on the Estimation of the Gravities of Fats. By G. W. Wigner, F.C.S. . . 35 Meeting of the Society of Public Analysts . 35 Paragraphs . , . . . . 35 A. H. ALLEN, F.C.S. J. FALCONER KING. A. WYNTEB BLYTH, N.R.C.S. R. H. HARLAND. C. A. CANERON, M.D. E. W. T. JONES, F.C.S. C. H. PIESSE, F;C.S. F. J. LLOYD, F.C.S.

ISSN:0003-2654    

DOI:10.1039/AN8760100017

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

ON THE DETERMINATION OF QUININE. By A. H. ALLEN, F.C,S. Read at a Neetiny of The Society of PzchGc Anazylsts, Fee6. 16th) 1876. BEING desirous of testing the accuracy with which prescriptions were dispensed in Sheffield, I recently had some mixtures made up of which Sulphate of Quinine was the principal constituent, solution being effected in the usual way by the addition of dilute sulphuric acid, and the mixture being sweetened by an admixture of simple syrup.One of the prescriptions was arranged to contain 2 grains, and another 5 grains per ounce, of Sulphate of Quinine. The method adopted for the estimation of Quinine in the above mixtures, has no claim to novelty, but experience having shown it to possess certain advantages, and to be susceptible of very considerable accuracy, besides being applicable to the estimation of quinine under a variety of circumstances, I have thougbt it worth while t o record my results in detail.In brief, the method employed consists of the concentration of the solution to a small bulk, addition of ammonia in moderate excess, agitation of the liquid with ether, and removal and evaporation of the etherial solution.The concentration of the solution appears to be of secondary importance except with regard to the economization of ether. As a rule, I prefer to manipnlate on 200 to 350 fluid grains (12 to 15 c.c.), of solution, concentrating the liquid to about that bulk if necessary. The concentrated liquid is introduced into a long tube or cglinder, of a capacity of about 800 or 1000 gr., furnished with a tightly fitting cork or stopper.20 THE ANALYST.Enough ammonia is then added to leave a distinct odour of the gas, and then a volume of ether about equal to that of the liquid already in the tube. The cork or stopper is inserted, and the tube vigorously agitated for a minute or two. When brought to rest, the ether and aqueous liquid usually separate rapidly.(Separation is often facilitated by cooling the tube in a stream of water. I n warm weather this precaution should always be taken, to prevent loss of ether from the ebullition which sometimes occurs spontaneously on opening the tube). I f the separation is difficult or imperfect, it may be induced with certainty by a further addition of ether and subsequent agitation. When the separation of the ether and waters is complete, the former is removed by a pipettet to a small weighed beaker, and the latter is shaken up with a further quantity of ether in a similar manner.It is seldom necessary to agitate with ether a third time, the amount of Quinine thus extracted being rarely weighable. The etherial solution of the Quinine when evaporated to dryness on a water-bath, leaves the alkaloid in a solid weighable state.I at first supposed that the Quinine obtained by the evaporation of the etherial solution, would exist as trihydrate (C22 H*2 N2 02 + 3 H2 0) ; the precipitate by ammonia being stated t o possess that composition. Further research, however, has conclusively proved this assumption t o be erroneous, as the following experiments show.A sample of Howard’s Sulphate of Quinine was completely analysed. The water was determined by drying at 110 deg. C., the sulphuric acid was precipitated as Ba SO , and the quinine was determined by the above described process, vie. : addition of ammonia and agitation with ether. It was conclusively proved that agitation of the ammoniacal solution with ether removes the whob of the Quinine, the aqueous liquid showing no fluorescence when strongly acidified with sulphuric acid, and giving no green colour with the bromine and ammonia test.For convenience of comparison, I have also stated the percentage composition of cryetalliced sulphate of quinine, containing 7 H20, and 8 H20. The freshly prepared salt is said to contain 8 H20, but practically that amount of water is not met with, owing to the rapid efflorescence which occurs.It will be seen that the sample in question gave results agreeing very closely with the composition of the 7-atom hydrate. The mean of the indirect estimations of Quinine, obtained by subtraction of the sum of the percentage of water and sulphuric acid from 100.00, is 3.31 per cent., less than the mean of the direct estimations by agitation with ether.The known hydrates of Quinine have the following percentage composition as compared with the residue from the ether. The Sulphate of Quinine in question gave the following results. (See Table foot of next page.) Quinine, Water. Trihydrate (C2oH24N 20 2+ 3 H2 0) 85.71 per cent. 14.29 per cent, Monohydrate (C20H24N 2 0 2+ H2 0) 94-74 ,, 5826 ,, Ether Residue ...... ... ... 95.72 ,, 4-28 ,, * Cinchonnia and other alkaloids insoluble in ether, are indicated here at the junction of the two fluids, as described by Mr. W. W. Stoddart. Magnesia partially remains as a flocculent precipitate in the aqueous solution. t The pipette should be furnished with a piece of narrow india-rubber tubing, so as to allow the eye t o be brought into a convenient position for observing the progress of withdrawal,THE ANALYST.21 It will be seen, therefore, that the ether residue contains about one per cent. less water than corresponds to the monohydrate. In two of the above estimations of Quinine, the alkaloid was determined by ooncen- trating the filtrate from the sulphate of barium precipitate, adding ammonia and shaking with ether.In the other cascs the quinine was determined in separate portions, cane sugar being added in two instances. Of the three experiments giving upwards of 77.9 per cent. of residue, one was made in the Bas04 filtrate, and two in separate quanti- ties, of which one contained sugar. It appears, therefore, to be fully established that the etherial residue is of constan- composition, approximating to that of the monohydrate of quinine.Crystallized sulphate yielding '77.59 per cent. of residue, the amount of the former can always be found by multiplying the weight of the residue by 'E0- 77.59-1'289. I f the quinine sulphate has undergone efflorescence of course the amount will be over-estimated. The crystallized salt is liable to lose water till it approximates to the cornposition of a 4-atom hydrate.I f the salt used have really this composition, and the ether residue be multiplied by the above factor, the calculated factor will be 106.6 per cent. of the true amount. It is evident, therefore, that the results are liable t o be in excess of the truth. As an example of the accuracy of which the process is capable in practice, I may quote the following results obtained from the analysis of a sample of sulphate of qui- nine which had been very much exposed to the air, and which, therefore may be assumed t o have possessed a composition approximating t o that of the 4-atom hydrate.Unfortu- nately neither the water nor sulphuric acid was actually determined. It will be observed that most of the estimations were made on very small quantities, and that the substance obtained is of less weight than the substance sought, instead of greater weight, as is umal in analysis. The addition of a large excess .of ammonia was not found to affect the accuracy, and equally good results were obtained by the use of soda.A considerable quantity of cane sugar was added to the solution in each case.(CZoH24N2 0 2 ) 2H2 SO4 + 8H2 0 (C20H24W 0 2 ) *H2 SO4 + 7H2 0 Experimental Results :- (=890) ... (=872).., 1 . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . 6 . . . . . . . . . . .. . . . . . . . . . 7 . . . . . . . . . . . . . . . . . . . . . Mean . . . . . . . . . I I Water. HZSO4 16'18 11.01 14'45 11-24 14-18 11-35 14'41 11.30 ... ... ... ... ... ... ... ... ... ... 14'395 11.325 Calculated. Found. 74-31 ... ... ... ... ... ... ... 74.28 77-93 77-92 77'14 77'45 77-05 77'73 77-91 77.5922 X 1.289 = 7 atom hydrate. THE ANALYST. )( -938 = 4 atom hydrate.DETERMINATIONS OF SULPHATE OF QUININE IN SOLUTIONS CONTAINING MUCH CANE-SUGAB. L Mean. Quinine Sul- phate taken. ...... Ether Extract. 1-61 grains 1.66 ,, 2.49 ,, 8.21 ,, 2.47 ,, 2.49 ,, 2.51 ,, ...... = per cent. 80.5 83'0 83.0 82.1 82-3 83.0 83 -6 ...... 103.7 per cent. 107'0 ,, 107.0 ,, 105.9 ,, 106.2 ,, 107.0 ,, 107.7 ,, 97.3 per cent. 100.4 100.4 101.0 106-36 per cent. I 99.71 per cent.I The above are all the determinations of quinine which were made on the sample in question. Experiments 1, 2, 3 and 5, were made with a very large excess of ammonia ; experiment 4 with a slight excess. In experiment 6 soda was substituted for ammonia. I n experiment 7 a large excess of sulphuric acid was employed to dissolve the Quinine, and the solution was evaporated until considerable charring of the sugar had occurred.The ether residue was somewhat coloured. The above results clearly show that the method is fairly accurate, and the results remarkably constant, considering the small amounts employed in each experiment. Of six mixtures containing sulphate of quinine and simple syrup, which were made up by druggists in Sheffield from a physician's prescription in the usual way, four were found by the above process to contain the prescribed amounts within reasonable limits af variation, while in two, the amounts of sulphate of quinine found were respectively about 6 and p of the prescribed quantities.I next tried if the process was applicable to the estimation of the quinine in the citrate of iron and quinine. This preparation is stated in the British Pharmacopceia to yield on addition of ammonia, a precipitate of quinine amounting to 16 per cent.of its weight. There is no mention made of any washing t o which the precipitate is t o be subjected, and no directions are given as to the mode of drying. As a matter of fact an exceedingly gentle heat causes agglomeration of the precipitate, and prevents its removal from the filter.In consequence of the solubility of quinine even in cold water, even careful washing causes a perceptible difference in the result. On this account, I estimated the total quinine in a sample of Howard's citrate, by precipitating the solution with a slight excess of ammonia, rinsing the precipitate off the filter and evaporating the rinsings and drying the residual quinine at 100 deg.C. The filtrate from the ammonia precipitate was concentrated, and the quinine extracted by agitating with ammonia and ether. I n one experiment, the precipitated hydrate of quinine was washed with cold water, in the other it was left entirely unwashed. I n fine, the Pharmacopceia instructions are very imperfsct. The results were :- Unwashed.Washed. Precipitated Quinine ....................................... 17.71 per cent. 15.13 per cent. ................................ 1.32 ,, Ether-residue from filtrate -83 9 , t? ,, washings none .............................. - -- 18.54 16.45THE ANALYST. 23 According t o the above results this sample of citrate comes up to the British Phar- macopoeia standard of yielding 16 per cent.of precipitated quinine, if the precipitate be left unwashed, but washing brings it below the proper amount. Twa experiments were made by treating a strong solution of the citrate with excess of ammonia, and then agitating with ether in the usual way, when I obtained 16.35 and 16-40 per cent. of ether residue, a result which shows a very close accordance with that previously obtained.The ether process is remarkably easy of execution in the case of the citrate of iron and quinine, not requiring more than some twenty or thirty minutes for its completion, and I think it would advantageously replace the present unsatisfactory and badly-detailed Pharmacopoeia process. I have also tried the applicability of the ether process to the determination of the Quinine in the official wine and tincture, but the results were somewhat in excess of the truth, owing t o the presence of foreign matter of the orange taken up by the ether." On the whole, it is evident that the ether process is capable of giving results which, under favourable circumstances, are strictly accurate, and in others it leaves the quinine in a convenient and nearly pure state for further examination.As my object was pri- marily to effect the accurate determination of quinine in the presence of sugar only, I have not worked out exhaustively the problem of estimating it in complex liquids, and have rather aimed at the determination of the total aZJeaZoid present than that of the actual Quinine, as distingnished from other cinchona bases.My acknowledgments are due t o Mr. L. N. Lean who has given me valuable assistance throughout the investigation, and has personally performed many of the manipulations. DISCUSSION. Dr. Muter said that certainly the process employed by Mr. Allen was a good one, and he had had considerable experience of it. It was a process invariably taught in the South London School of Pharmacy, as the best method of separating the alkaloids from scale preparations, with this difference, that there chloroform is preferred to ether ; be, cause with ether quinine and quinicine only are extracted, whilst with chloroform you also get cinchonine and quinidine.This is important, as the chemist might have used unwittingly quinine containing cinchonine. Instead of weighing the ether residue in estimating quinine he considered it preferable to either get it as a definite neutral sul- phate, or to precipitate it as herapathite, the latter being veiy constant in composition, one part dried at 212 representing -565 of quinine.I n the examination of orange wine for quinine, the acid liquid should be first washed with ether, which removes matters soluble in that liquid other than alkaloids.He had frequently applied this process to the detec- tion of quassine and gentianine in supposed pure quinine bitters. The agitation of the acid solution with ether or chloroform, as a rule, separates bitter principles and glucosides, and as far as he knew only one alkaloid, viz. colchicine, comes out to ether in the pre- sence of an acid. A process of titration for the estimation of emetine in ipecacuanha is given in his (Dr.Muter's) book on Pharmaceutical Chemistry, which is very rapid and simple, and might be easily applied also to quinine in a mixture. * The discussion on the paper having elicited valuable suggestions from several chemists, respecting the determination of the alkaloid in the wine and tincture of quinine, I think it better to reserve the further description of my experiments till I have had the opportunity of supplementing them.-AH.A,24 THE ANALYST. Dr. Stevenson said that some time ago when investigating the strength of quinine wine, he had successfully used the process of precipitation by ammonia, and extraction with ether, as described by Mr. Allen. The wine was merely boiled so as to drive off, the alcohol, and not concentrated to mch an extent as the author of the paper had described; but four or five shakings with ether were practised.Dr. Stevenson had found that by using a quinine salt of known composition, and calculating on the assump- tion that the ether residue was a monohydrate, satisfaciory results were obtained. Indeed, he thought he had seen it stated on good authority that the ether residue was a monohydrate of quinine.There was some doubt respecting the true formula of di- sulphate of quinine. The B.P. assigns to the salt 7 molecules, the French codex, 73 molecules, and the U.S. Pharmacopeia, 8 molecules of water. It was doubtful whether the salt contained usually 7 or 7% molecules of water, and it appeared to be pretty certain that it did not contain 8 molecules.The commercial article is perfectly dehydrated by exposure in the water bath, andcontains about 14 per cent. of water as stated in the B.P., but being a very efflorescent salt, the percentage of water might be very much less than the above quantity. Dr. Dupr6 enquired if Mr. Allen had tried the volumetric estimation of quinine by means of a standard solution of the double iodide of potassium and mercury, which was said to give excellent results? He congratulated Mr.Allen on the courage he had dis- played in raising a discussion on such a subject, remarking that his own experience showed that a considerable amount of adulteration was practised in relation to drugs and medicines ( i e . , if the leaving out of an appreciable proportion of the active agent is to be considered adulteration).He had noticed, moreover, that chemical compounds, such as sulphate of quinine hydrochlorate of morphia, iodide of potassium, &c., &c., were nearly always found to be pure wherever purchased, whereas all compound drugs and medicines which should con- tain a certain definite proportion of an active ingredient, were frequently deficient in that ingredient, and must therefore be looked upon as adulterated.Mr. Wanklyn made a few remarks. Mr. Thomson drew attention to some of the results which he had obtained in the I n replying, Mr. Allen said that he made no claim to having originated the process, though he believed the extent to which it r a s capable of giving accurate results had not been pre- viously investigated.With regard to Dr. Muter’s valuable suggestion that accurate results might probably be obtained from the wine and tincture of quinine, by agitating first in an acid solution, he might say that he had observed that quinine was absorbedby ether, from acid solutions (probably as sulphate), to a sufficient degree to vitiate the results; but if chloroform be substituted for the ether, as suggested by Dr.Muter, he had no doubt the de&ed object would be effected. Mr. Wanklyn’s suggestion, that the actual quinine in the ether residue, could be ascertained by titration with standard acid, seemed admirable, especially if some acid soluble in alcohol were employed.* As to the temperature of dehydration of quinine sulphate, he had employed 110 deg. C for the pur- pose, but it was interesting t o learn from Dr. Stevenson, that the salt became anhydrous at 100 deg. C. Mr. Allen did not at all contend for the presence of eight, or even seven and a-half atoms of water in the crystallized sulphate. He had been merely interested analysis of compound medicines.THE ANALYST. 25 in the water indirectly, and quite agreed that more water than corresponded to seven atoms was not met with in practice. As far as he could ascertain, the existence of the monohydrate of quinine had previously been doubtful, and the dihydrate was apparently entirely new.?- For the estimation of the iodide of potassium in the medicines he had recently condemned in Sheffield (and which merely contained aromatic spirits of am- monia in addition), Mr. Allen said he had precipitated one quantity as iodide of silver, after acidifying with nitric acid, and another in the original solution, by ammonio-nitrate of silver. The agreement in the weight of the two precipitates proved the freedom of the iodide of potassium employed from any sensible admixture of chloride, bromide, or iodate.

ISSN:0003-2654    

DOI:10.1039/AN876010019b

出版商:RSC    

年代:1876

数据来源: RSC

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THE ANALYST. 25 in the water indirectly, and quite agreed that more water than corresponded to seven atoms was not met with in practice. As far as he could ascertain, the existence of the monohydrate of quinine had previously been doubtful, and the dihydrate was apparently entirely new.?- For the estimation of the iodide of potassium in the medicines he had recently condemned in Sheffield (and which merely contained aromatic spirits of am- monia in addition), Mr. Allen said he had precipitated one quantity as iodide of silver, after acidifying with nitric acid, and another in the original solution, by ammonio-nitrate of silver.The agreement in the weight of the two precipitates proved the freedom of the iodide of potassium employed from any sensible admixture of chloride, bromide, or iodate.LIQUOR ANMONIB ACETATIS, B.P., BY J. THRESH, F.C.S., (Pharmaceutical Journal, 3rd Series, No. 301, 1876, p . 787.) MR. THRESH comments upon the varying strength of Liq. Amm. Acet. ; he analysed seven samples, three of which were purchased from wholesale, and four from retail chemists, with the following results (No. 1 was prepared by himself, Nos. 5, 6, 7 and 8 were concentrated preparations labelled as stated)- 4 6 (1.5) 7 (1.7) 8 (1.7) 5 (1.2) Re-action.Neutral . . . . . . Str&gli Alkali& Alkaline.. . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sp. Gr. 1.016 1-016 1-015 Not taken 1.018 1.014 1.011 1.015 Action of S€12. No Colour ... Slight C olour Wone ... Slight Colour Deep Colour Slight Colour 9 9 9 9 Per Cent. of Ammon.Acet. 6.9 7-0 6'5 4.6 7.9 5.8 4.9 6.5 Mr. Thresh thinks that in the next edition of the B. P. the solution should be made with solution of ammonia instead of with carbonate, that the characters, tests, &c., should be added, and that it should be directed to be kept in green glass bottles to avoid contamination with lead. A. W. B. PERSIAN OPIUM. Mr. W. D. Howard [Phmmaceut. Journal, 1876, No. 298, p. 720,) has recently analysed a. sample of Persian opium. The andried substance yielded- Per cent. Morphine Crystallised from aicohol ... 10.40 Codeine (anhydrous) ... ... 0.29 Narcotine ... -.. ... 2.50 Thebaine ... ... .. 0.57 Cryptopine ... ... .I. 0.09 Papaverine ... ... ... trace A. W. B. ~- - 0 Since the above paper was read I have obtained very encouraging results by titration.-A. H. A. t The description of the elements proving the existence of these hydrates is omitted from the present paper.

ISSN:0003-2654    

DOI:10.1039/AN8760100025

出版商:RSC    

年代:1876

数据来源: RSC

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26 THE ANALYST. THE DETECTION OF THE COLOURING MATTEkS OF LOGWOOD, BRAZIL WOOD, AND COCHINEAL I N WINE, BY A. DUPRE, PH. D., F.R.S. Read at the Animal Jfieting of the (I Society of Public Analysts,” held January 26th) 1876. LOGWOOD, Brazil Wood, and Cochineal are said to be frequently used for imparting colour to wine, though I must confess that I have never found them in any wine I have examined.It is however but fair to add that until recently I knew of no, fairly reliable, method for detecting the presence of two at least of the above colouring matters, sup- posing them to have been added for the purpose of modifying the colour of a naturally red wine. Sorby’s experiments have been made with fresh solutions of the colouring matters experimented on, and as these matters when in solution change t o some extent in process of time, his experiments cannot be safely used for the examination of a wine without some further investigation. The following simple process, based on experiments made mith solutions about a year old, will however, I believe, answer all requirements.The natural r ed colouring matter present in wine% is incapable, or almost incapable of dialysis, whereas the above colouring matters dialy se, comparatively speaking, readily I n order therefore to test a wine, we simply set it to dialyse for two or three days when, if it be pure,? a trace only of the colouring matter will be found t o have passed through the dialyser, and what little has passed will have the colour of the wine rery much diluted.If, however, the wine contains any of the above mentioned colouring matters the water outside the dialyser will be found of a marked yellow or brownish yellow colour, very different from that of the wine inside the dialyser.This solutiou may now be used for obtaining the chemical, and optical reactions of the colouring matter free or almost free, from the interfering influence of the natural colouring matter of the wine.I n the case of logwood and brnzil wood, these tests do not yield the same marked and characteristic results in the old, which they yield in the fresh solutions. I will therefore, not attempt to describe them, but would rather advise everyone who intend making such examinations to keep some infusion or tincture of the woods, of known age, in his laboratory, so as to be able to compare their respective reactions directly with the inspected colouring matter obtained from the wine.The colouring matter of cochineal yields however, three well marked absxbtion bands when its ammoniacal solution is examined by the spectroscope, and by means of these bands the presence of even a small proportion of this colouring matter may be recognized in the wine itself.The portion dialysed, yields these bands however somewhat more sharply. Other colouring matters said to be sometimes employed in the manufacture of wine, may perhaps be separated by similar means, and I hope some members of this Society may be induced to try experi- ments in this direction. I n conclusion, I would remark, that the parchment paper to be used in these experiments, should be of good substance, and that great care should be taken in fixing it over the dialgser so as t o prevent the setting up of capillary action between the folds of the paper, by means of which, portions of the contents of the dialyser pass over into the outer vessel producing effects which may be mistaken for true dialysis. * I have examined Clvaret, Red Rhine Wine, and Australian Wine, and Port Wine, and have no doubt t.The natural colouring matter of a pure wine will not dialyse, from this however it does not follow The colouring matter most other natural Red Wines will behave in a manner similar to these. that a wine, the colouring matter of which does not dialyse, is therefore pure. from Rhataiiy Koo; fur example I find does not dialyse.

ISSN:0003-2654    

DOI:10.1039/AN8760100026

出版商:RSC    

年代:1876

数据来源: RSC

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THE A4NALYST. 27 ACCURACY I N DISPENSING. The panic created By the investigation into the manner in which Dispensing Chemists “make u p ” the prescriptions presented to them, which, in the course of his official duties, Nr. Allen, the Analyst for the Borough of Sheffield, recently instituted, will be fresh in the memory of our readers, but the sequel may not be so widely known. Mr. William Thornson, of the R,oyal Institution, Manchester, determined to extend the range of the examination which Mr.Allen had commenced, and, with that view, had two pre- scriptions made up in a large number of towns and cities in different parts of England and Xcotland. The results of this investigation, which were necessarily of considerable interest, Mr. Thomson proposed to communicate in the form of a Paper, “ On the degrees of Accuracy displayed in the Dispensing of Physicians’ Prescriptions by Druggists in different Towns throughout England and Scotland.” I t was intended to be read at a Meeting of the Pharmaceutical SocietS on the 1st of Harch, and an explicit announcemmt$hat it would be so read appeared in the Pharmaceutical Journal of February 26th, but notwith- standing such official notification, the Paper mas not read before the Pharmaceutical Society either on the date named or on any other occasion.The reason for the rejection of the Paper mas given, somewhat tardily, in the Pharmaceutical Society’s Journal of March 11th. It appears that ( L when the nature of the Paper became known the trivial “ and insufficient nature of the grounds upon which conclusions were drawn was so manifest, that it was decided not to accept the Paper,” even though the acceptance of the Paper had been already officially announced.Mr. Thomson, however, found an audience if not in Bloomsbury Square, and read his Paper before the Manchester Philosophical, Society just a week after it was intended to be read before the Pharmaceutical Society.The strangest point in the affair is, how- ever, that whilst Mr. Thomson’s Paper was rejected by the Pharmaceutical Society, and ignored by its organ, the Chemist and Druggist ” published it in extenso, having received the manuscript a t its own solicitation. It should be a matter of congratulation t o the trade that they possess in the I ‘ Chemist and Druggist ” an organ which does not fear a fair discussion, but honestly opens its columns t o both sides.This Paper has rather a curious history. POTASSIUX IODIDE. Mr. Thos. F. Best, F.C.S., [Pharrnaceut Journal, 1876, No. 298, p. 7201 has ana- lyzed some samples of commercial iodide of potash, and calls attention to the presence of an excess of alkali, chiefly in the state of carbonate. per cent. No. 1 contained ... ... 5.44 ... ..~ 5.35 ... ... 2.32 ... ... 1.76 t.. 1.. .53 ,f 2 ? I ?7 3 ’ ?’ ?, 4 ,9 11 5 ?, From the author’s practical experience he considers that commercially pure iodide should not contain more than from 15 to 20 per cent. A. W. B.

ISSN:0003-2654    

DOI:10.1039/AN876010027b

出版商:RSC    

年代:1876

数据来源: RSC

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28 THE ANALYST. THE PREPARATION OF DEXTRINE-MALTOSE (MALT SUGAR) AND ITS USE IN BREWING. BY WM. GEO. VALENTIN, F.C.S., ROYAL COLLEGE OF CHEMISTRY, SOUTH KENSINGTON. A6stracted from ‘( Journal of Society of Arts,” Nwch 24th) 3 876. THE author describes some improvements made by himself and Mr. Cornelius .O’Snllivan, in the preparation of a sugar for brewers’ use. I n order to show the advantage of dextrine-maltose, the author first dwells upon the composition of malt, showing that by a study of the constituents contained in malt before and after infusion, in connection with those contained in the fermented beer, much additional insight into the brewing process may be gained.The published analysis of malt are, upon the authority of Mr. O’Sullivan, not to be relied upon. Oudemans states that malt contains 8 per cent.of dextrine, O’Sullivan cannot find any ; again, the amount of sugar is usually set down at from -4 to 1 per cent ; O’Sullivan finds from 16 to 20 per cent. About half of this is due to the transformation during the malting process of starchy matter, the remainder of the sugar is ready forrned in barley, and differs from the one produced by malting.The starch of barley contains a carbohydrate of the type having a laevo-rotatory action on polarised light. Kiihnemann calls this body ‘‘ Sinjstrin,” but from its general charac- ter, O’Sullivan is inclined to think that it is ‘ I Inulin.” The following table gives the detailed composition of two samples of pale malt, every item of which has been estimated directly and not by difference :- Malt No.1. Malt No. 2. Starch ... ... ... ... 44.15 45.13 Other Carbohydlates (of which 60 to 70 per cent. c&sist of fer- mentable Sugars) Inulin (a), and a small quantity of other bodies soluble in cold water *.. ... ... 21-23 19.39 Cellular matter ... ... ... ... ... 11.57 10-09 Fat ... ... ... ... ... ... 1-65 1.96 Albuminoids- water ... ...... -63 -46 (a) Soluble in alcohol of sp. gr. *820 and in cold (c) Insoluble in cold water but soluble a t 68O to 70° C 2.37 1.36 (a) Insoluble a t 68d”io 70Q C; but s o l h e in cdii (e) Insoluble in cold water and at 70” C ... 6.38 8.49 (a) Soluble in cold wkkr and at, 68“ C ... 3.23 3.12 water (albumin proper) ... ‘.. -48 ‘37 - 13’09 - 13.80 Ash ... ... ... ... ... ... 2.60 1.92 Water ...... ... ... ... 5.83 7.47 100.12 99.76 - When ground malt is submitted to the mashing process, certain of the albuminiod bodies contained in the malt act upon the starch, and the latter is dissolved. The wort, therefore, contains the transformation products of the starch, principally dextrine maltose of the other carbohydrates, the soluble albuminoids, the soluble portion of the ash, and a little soluble fat. Boiling with hops removes a portion of the albuminoids, but the starch products are but dightly altered.THE ANALYST.29 When the boiled hopped wort is suhsequently submitted to the action of yeast, the carbohydrates, other than those derived from starch, yield alcohol first, and the portion which is fermentable (60 to 70 per cent.) disappears almost altogether, aEd there remains in the beer, when the first stage of the fermentation is over, and when it is fit to go into the casks, the alcohol and a portion of the carbonic acid derived from the carbohydrates other than starch, and also from a portion of the products of the transformation of the starch itself, ieffected by the ferments. Hence the whole of the dextrine, a considerable portion of maltose, the remainder of the aibuminoids, the soluble matter of the hop, and a few other constituents are left for after fermentation.In order t o understand the part which the dextrine and maltose play in the after history of the beer, the author examined the constitution of a typical Burton Pale Ale, when the principal fermeutation was finished.The sample showed an original gravity of 1063, and gave when finished and ready t o be put into casks a distillate of spirit grains -993, equal t o 33.7 degrees of gravity lost. The unboiled wort of this beer, supppsing it had been brewed from No. 1 malt and reduced to the above specific gravity, viz. 1063, after allowing for concentration on boiling, would contain in every 100 parts by measure the following solid constituents :- Maltose ... ...... ... ... 6.66 Dextrine ... ... ... ... *.. ... 3.44 Ditto nnfermentable , . . ... ... ... 1.48 Albuminoids ... ... ... ... ... 1.45 ... ... Other Carbohydrates, fermenLible ... ... ... ... 3.30 Ash, Phosphates, Suiphatea, &c. ... ... ... ... 0.17 Total ... ... 16-50 - - After boiling with hop (and correction for loss by evaporation, so as to keep it at the normal original gravity of 1063) it was composed as follows :- Maltose ...... ... ... ... ... ... 6.66 per cent. Dextrine ... ... ... ... ... ... 3.44 Ditto unfermentable . . ... ... ... 1.00 Albuminoids ... ... ... 1-05 Hop extract .. , ... ... ... ... ... 0.33 Ash ... ... ... ... ... ... ... 0-27 Other Carbohydratls; fermentable ...... ... ... 3-80 ... ... Total ... ... 16.55 Hence it follows that the fundamental constituents of the hopped wort had under- gone but little change, when the principal fermentation with yeast was finished and the ale ready to be put into tshe cask, the beer contained :- Alcohol and solide in 100 parts. Alcohol ... ... ... ... 4-48 sp. gr. -992 Maltose ... ... ... 1.52 Dextrine ... ...... ... 3.44 Carbohydrates fermentable ... ... trace. Ditto, unfermentable ... ... 1.00 Albuminoids ... ... ... . -66 Hop Extract ... ... ... ... -33 Non-volatile Products of the Fermentation.. . -47 Ash ... ... ... ... ... -24 7.66 - - = If we examine the malt analyses given above, and suppose that during the mashing process the malt yielded an extract of 74 per cent., we perceive that the starch amounts to little more than 59.6 per cent.; the maltose and dextrine in the wort to a little more30 THE ANALYST. than 61 per cent. of the extract, the increase Seing due to the binding of water. This very closely corresponds t o the theoretical percentage of these bodies, obtainable, if starch splits up, according to the equation :- ClSH30015 + OH2 = C12H2011 + ~ 6 ~ 1 0 0 5 - '- - Starch.Maltose. Dextrine. that is, 32'15 per cent. of dextrine and 67%5 of maltose. If the composition of the boiled wort given above be examined, it will be found that about 64 per cent. is fermentable matter. I n all well conducted brewing operations, at the time of racking the beer, if the original gravity be determined, few instances will occur in which the amount of matter fermented is more than 64 per cent.of the original solid matter before fermentation. There may be cases in which this number is exceeded, as in old beers, in which the after-fermentation had taken place, or badly brewed beers, in which proper attention had not been paid t o the mashing opera- tion. It is pretty well understood that if a pale ale, the worts of which had, say a specific gravity of 1063-1064, can be got into the cask when it is reduced by fermenta- tion down to 1020-1021, things are going on rightly.The meaning of this is not far to seek. The wort would contain in every 100 parts, by measure, 16-5 parts by weight, or thereabouts of solid matter of the composition already referred to. The specific gravity of the finished beer being taken at 1021, the specific gravity of the spirit contained in the finished beer would be 992, or 8 less than 1000.The specific gravity of the finished beer, taken at 1021, the specific gravity of the beer without the alcohol would amount t o 1029 (1021+8). This represents 7.6 per 100 of solid matter, or 16.5-7*6=8-9 of converted matter, and when expressed in percentage numbers=53.9, say 54 per cent., thus leaving still in the beer, as shown above, about 10 per cent.(on original extract) of fermentable matter. This matter is maltose, and it serves to keep up, by its slow and gradual fermentation, the condition of the beer in cask. Malt being sweet, and it not being understood t o what the sweetness was due, cane sugar, invert sugar, and glucose, or so-called saccharines of various kinds have been pro- posed as substitutes.I f cane sugar be submitted to the action of yeast, it will be found, if sufficient yeast be added, and the temperature of the mixture be maintained at from 20° to 30° 0. that the whole of it ferments in four or five days, and yields 51 to 51.5 per cent. of alcohol, together with a certain proportion of succinic acid, glycerine, and other products. The residue left on fermenting ti portion of the cane sugar always tastes acid and '' thin ; " the acid taste is no doubt due to the succinic acid, and the thinness t o the peculiar sharp bodiless taste of the sugar.I f one-third of the malt extract in the pale ale mentioned above be replaced by cane sugar, the wort before boiling would then have the following composition :- Per 100 parts by measure, Cane Sugar ...... ... 6.67 ... 3,. ... 4-63 Maltose ... Dextrine ... ... ... ... 2014 Other Carbohydrates, fermentable ... 2.20 Ditto, non-fermentable ... ... 0.99 Albuminoids ... ... ... 0.98 Ash ... ... ... ... 0.11 16.62THE ANAliYST. 31 No. 1. No. 2. 1 No. 3. Glucose . . . . . . . .. 80.0 58.85 67.44 Maltose . . . . . . . . . None. 14.11 10.96 Dextrine None. 1.70 None. Neutral carb%ydrai&, with‘ Ash . . . . . . . . . . . . 1.3 1.40 1.60 Water . . . . . . . . . 10.5 14-56 15.70 ---____- a little albuminoids ] 8.2 9.38 4.30 Total ... ... 1100.00 100*00 100~00 Total solid matter . . . . . . 1895864484.3086.8284.80 74-66 78.40 Percentage of matter of use 1 I 80.0 to the brewer ...After boiling with the hop it would contain- Per 100 parts by measure. Cane Sugar ... ... ... 6.57 Maltose ... ... ... ... 4.53 Dextrine ... ... 2.14 Other Carbohydrates;’fermeniible . . , 2.53 Ditto, non-fermentable ... ... 0.66 Albuminoids ... ... ... 0.70 Hop Extra2t ... ... ... 0.39 Ash ... ... ... ... 0’21 No. 4. No. 5. 63.42 61.46 13.50 13.20 None.None. 8.40 8.60 1.50 1.60 13.18 15.20 ________-- 100~00 I 1co.00 76.92 74’60 16.73 The analysis is of a beer in which the same amount of hops was used as in the previous case. The numbers are before fermentation. It contains- Cane Sugar ... ... ... 5.57 Maltose ... ... ... ... 4.53 Fermentable Carbohydrates ... ... 2.53 12-63 in 16.73 parts, i.e., ’75 per cent. of fermentable matter.Cane sugar can never be used as a substitute for malt in the brewing of keeping beers. Keeping, even for a short time, attenuates them so much, that all body and flavour are gone. The analysis of two samples I have before me. They appear as semi-solid, straw-coloured, honey- like substances. No. 1 gave 85 per cent., and No. 2, 86.88 per cent. of solid matter. Hence 85 parts of cane sugar would go as far as 100 parts of No.1 ; and 86-88 of cane sugar as far as 100 parts of No. 2 ; but 100 parts of cane sugar yield 105.26 parts of invert sugar. The next substance t o be dealt with is the so=caUed ‘; invert sugar.” Per centage composition of two samples of so-called Invert Sugar. No. I. No. 11. Cane Sugar ... ... ... 13 26 Invert Sugar ... ... ... 87 74 - 100 100 - - Their value as substitutes for malt can be easily estimated from what has been said above upon cane sugar, and from the fact that invert sugar only yields from 48 to 49 per cent. of alcohol, by fermentation.The next set of bodies are the so-called ‘; saccharines,” or glucoses, &c., produced by the action of sulphuric acid upon starch or starchy substances. The following are analyses of five samples of saccharinas from different makers :- Sample KO.1.-Rather brown ; very hard ; English manufacture. Sample No. 2.-Pale straw coloiir ; softish ; French manufacture. Sample No. 3.-Rather white ; somewhat hard ; English manufacture. Sample No. 4.-Rather white j somewhat hard ; German manufacture Sample No. 5.-Whiter ; somewhat hard; German manufacture.32 TEE ANALYST.These analyses require little explanation, and very little comment of any kind. The glucose is of the C6 "12 06 type, and yields only 48 to 49 per cent. of alcohol, on fermentation. The neutral carbohydrates are useless to the brewer, for although they increase the specific gravity of the beer, they are devoid of taste and '' body-giving " properties.They, under no condition, yield alcohol, and cannot be converted like dextrine by the slow and gradual action of the beer into bodies capable of yielding this substance. If the analyses of these saccharines be examined and compared with that of the malt- wort, it will be seen that they have only one constituent in common, viz., maltose, and this exists in the saccharines in such small quantity as to be of little consequence.A slight consideration of the composition and properties of dextrine-maltoae will show at once its great superiority over all other malt substitutes offered t o the brewer. It contains in 100 parts in round numbers :- Maltose ... *.. .*. ... ,.. 67 Dextrine.. . ... ... ... ... 33 - 100.0 Maltose yields the same proportional quantity of alcohol as cane sugar does, and the alcohol it yields is, in flavour, as far superior to the raw alcohol of the glucose of the saccharines, as that of fine malt whiskey is t o potato spirit.In fact, the fine flavour of malt spirit is due to the fermentation of maltose, and that of the so-called potato spirit, to that of glucose. This is another reason why the saccharines have not come into more general use.There is far more yeast forming albuminoid matter in malt-wort than is required to ferment its saccharine constituents, aad an addition of dextrine-maltose in varying proportions will have the additional effect of removing a further quantity of this yeast-forming matter from the beer before it goes into the casks. I n the manufacture of dextrine-maltose, when rice is employed it should be husked and finely ground.The rice-meal is first steeped in from 1 to 14 times its weight of cold acidulated water, or in water not higher than 404 C, and thoroughly agitated by mechanical means. I t is then gradually introduced into acidulated boiling water, in the proportion of 100 parts by weight of rice to 250 by weight of the latter, care being taken not to allow the temperature to fall much below 90Q C.The amount of acid-by preference sulphuric-may vary. A dilute acid is preferable, for although the converting action is not quite so rapid, it pro- ceeds much more regularly. The vessel in which the rice-meal is converted consists of an ordinary mash tun, lined with sheet lead and provided with steam coils and a stirrer.As soon as the rice has become thoroughly diffused throughout the boiling water, a rapid conversion is ob- served. The liquid boils up briskly, and the steam has to be checked for a while to prevent its boiling eyer. The rice-paste becomes rapidly thinner, when kept at a boiling temperature for about an hour or an hour and a-quarter. It is best and most expeditiously tes ed by neutrdising a sample with baryta-water or chalk, filtering and examining the clear solution by means of the polariscope.We employ from 16 t o 2 or 3 parts per cent. This action is evidently owing to a chemical change.THE ANALYST. 33 The conversion may be considered complete when the rotatory power is + 1710 or thereabout, indicating two parts of maltose (rotatory power -!- 150") and one part of dextrine (rotatory power -k 213*), L e .2 X 150° + 213Q = 171' 3 By always infusing the same quantities of rice-meal and keeping up the same temperature, it is possible, after a few experiments, to dispense with the polariscopic determination altogether, and to obtain a liquor containing the proportionate quantities of dextrine and maltose, as they are found in malt-wort.The acid liquor is then carefully neutralised with good chalk to the extent of about 90 per cent., finishing off with milk of lime. It is preferred to leave the liquor, however, rather a trifle acid than alkaline. The strength of the liquor, after filtering off the grains, and the gypsum through Taylor's filtering bags, usually amounts t o 1,115 to 1,125, or 30 to 32'5 per cent. of solid matter, i.e., about double the strength or original gravity of malt-wort required for brewing strong ales. It is next evaporated either in an open pan, or with greater advantage in a vacuum pan, to a concentration of about 1,200, or about 52 per cent. of solid matter. A little more gypsum and a little flocculent albuminoid matter are at this stage best separated by filtration, and the concentrated liquor finished off in a properly constructed vacuum pan, or in an open steam-jacketed pan, provided with an agitator, till it acquires a stiff viscidity: It is then run off hot Pato forms, and cast into cakes of convenient weight, which on cooling, set hard, and are ready to be sent to the brewery. 78 to 80 per cent. of the starch in rice, in fact every particle, can be converted into dextrine-maltose. This operation can be carried out with the greatest delicacy. It is of a light amber coloin and filters very readily. The cost of manufacture is not more than 25s. to 30s. per ton. R. H. H.

ISSN:0003-2654    

DOI:10.1039/AN8760100028

出版商:RSC    

年代:1876

数据来源: RSC

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THE ANALYST. 33 PROSECUTIONS UNDER THE SALE OF FOOD AND DRUGS ACT. At Alfreton Petty Sessiona Mr. Alfred Schofield, grocer, Market-place, Alfreton, was charged with selling +lb. of caper tea, on the 15th March, which was adulterated with minerd matter.-The prosecutor went into the shop of the dcfendant, and asked the assistant for 2lb. of caper tea, which was supplied to him, for which he paid 1s.2d. He divided it in three equal parts, and sealed the parcela. One he left, one was for- warded to the public analyst, A. H. Allen, and one he kept.-It was deposed by the analyst that he examined the tea, and found that it was adulterated with 8 per cent. of mineral matter, 6 per cent. of which was small stones rolled up in the leaves.-Mr. Schofield stated in defence that the tea was old stock, and was sold precisely as he bought it.It was not kept in the shop, and was only supplied when customers asked for it. He had learned since the information that it was often adulterated, but did not know that when he sold it.-Fined in the mitigated penalty of $ 5 , which was paid. THE FOLLOWING IS THE FIRST CASE FBOX SCOTLAND, of milk adulteration, which has been remitted to Somerset House.On the 11th of March James Mathie, Tnverkip, was charged before Sheriff Smith, at Greenock, with having sold a quantity of milk of the quality known as skim, which was not of the quality demanded by the purchaser;34 THE ANALYST. Mr. William McCowan, Public Analyst, deposed that he had analysed the milk referred to, and found that it contained at least 21+ per cent.of added water, and also 122 grains per gallon of added salt. After hearing agents for both parties, the Sheriff expressed his opinion that it would be well to have another analysis of the milk, since the analysis was disputed; it would be desirable that the public should know whether they could rely upon their analyst. The sample was then ordered to be sent to the Commissioners of Inland Revenue.The case was again called before Sheriff Smith, on the 6th of April, when the Inland Bevenue Chemist’s report was read, which was to the effect that considering the amount of decomposition which had taken place, they were of opinion that the milk had been adulterated with 24 per cent. of added water. They also found an excess of s a l t over and above that ordinarily found in genuine milk, to the extent at least of 80 grains per gallon.The Sheriff said, that as the evidence of Mr. McCowan had been fully borne out by the London chemists, he would impose a fine of S 2 2s. with $3 3s. for expenses. TEE PXACTICE OF ADULTERATING BUTTER -Prederick Dobell, butterman, of 68, Wellington-road, Kentish Town, was summoned by the vestry of St.Pancras for selling a quantity of adulterated butter.-It appears that the sanitary inspector went to the defendant’s shop and asked for a pound of butter, which was served him, and he paid Is. 4d. for it.-Dr. Stevenson, the public analyst, certified that in i t there was 75 per cent. of substance other than butter.-The defendant said he had sold the butter as he bought it from the wholesale merchant.He paid Is. 24d. per pound for it and sold it at Is. 4d Mr. Mansfield said he believed that for some time past persons had been sending bad butter from Holland.-It was mentioned that it was called ‘L bosh.” Mr. Mansfield ordered the defendant to pay a fine of $5 and 2s. costs. Thomas Lodge, butterman of 5, Prince of Wales-crescent, Eentish Town, was also summoned for a similar offence, and it was proved that the butter was adulterated 70 per cent.-The defendant made the same excuse as the last defendant, and was ordered to pay a similar fine, the magistrate stating that they could proceed against the merchants.At the Clerkenwell Police Court, four persons were prosecuted under the Adul- eration Act, with the following results : Alfred Willen, of 4, Corporation Buildings, Farringdon Road, was ordered to pay a fine of $3 and costs, or t o be imprisoned for one month, for selling milk mixed with 30 per cent.of water; Alfred Coker, general dealer, 4, Clerkenwell Green, was fined 10s. and 2s. costs, or in default of pay- ment seven days’ imprisonment, for selling milk adulterated with 11 per cent.of water ; John Ager, milkman, 150, Icing’s Cross Itoad, fined $3 and costs, or one month’s imprisonment, also for vending milk with 30 per cent. of water ; and a penalty of 20s. and Costs, with the alternative of fourteen days’ imprisonment, was inflicted on Theodore Eden, of 3, Weston Street, Clerkenwell. Bichard Cheviles, cheesemonger, of Hackney-road, was summoned before Mr.Bushby, by the vestry of the parish of St. Leonard, Shoreditch, for selling as butter an article which was adulterated-Mr. E. Walker, vestry clerk, supported the summons, and the defendant was represented by a solicitor whose name was not stated.-The purchase having been formally proved, the certificate of Dr. Stevenson, public analyst t o the parish was put in, and showed that the article purchased as butter was adulterated with common fat, not butter fat, at least 50 per cent.-TheTHE ANALYST.35 defendant, by his solicitor, said that he had purchased the (‘ butter ” of a salesman in Leadenhall Market, at the rate of about 14id per lb., and sold it the same as he received it at Is. 6d. per lb., and had no idea that it was adulterated. The defendant, called as a witness on his own behalf, admitted, however, that he did not think ((real ” butter could be sold for 1s.6d. per lb., and further that he had no warranty from the salesman that it was butter. He considered the case made out, and inflicted a fine of ~ O S . , and 2s. costs. The money was paid. THE URBAN ABND SUBURBAN MnK-cm.-An instructive case was tried last Saturday a t Bath, in which a milkman admitted that he carried two cans, the one containing pure milk, which he distributed in the suburbs, where there vas a public analyst ; the other a milk adulterated with at least 20 per cent. of water, which wag disposed of in the city, because there was no such official there !-Lancet. THE SALE OF FOOD AND DRUGS Acr.-William Lindsay Emmerson, N.D. Aberd., L.R.C.S. Edin., L.S.A. Lond., has been appointed public analyst to the counties of Leicester and Rutland for one year, vice Young, whose appointment has expired-1 0s. 6d. per analysis, minimum $70 for the year. Mr. Bushby said the warranty would have been a protection t o him.

ISSN:0003-2654    

DOI:10.1039/AN8760100033

出版商:RSC    

年代:1876

数据来源: RSC

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THE ANALYST. 35 NOTE ON THE ESTIMATION OF THE GRAVITIES OF FATS. BY G. W, WIGENER, F.C.S. THE small quantity of Butter received for analysis, especially in disputed cases, is frequently insufficient to fill even a small specific gravity bottle. In such cases the well known specific gravity ‘‘ bubbles ” may be used with advantage, even if the quantity of fat is as little as 200 grains. By adopting the following mode of procedure, only one or two bubbles will be required. Pour the filtered liquid fat into a test tube of suitable size, put in the bubble, cool the fat until the bubble just rises, then transfer the tube t o a suitable water bath, and raise the temperature of the water very slowly until the bubble begins to sink, read the temperature at this time for comparison with genuine butter.The following results mill show the bubbles likely t o prove most suitable. Two bubbles were selected, the sp. g. of No. 1 was 899-7, of No. 2 895.7, both of course taken at 60 F. In a sample of Butter Fat which at lOOQ F had an ‘‘ actual density ” of 913 No. 1 bubble sunk at 131° F ; No. 2 at 144* F. In another sample of fat, having an actual density of 911.3, No. 1 bubble sank at 123O F ; No.2 at 135Q F.36 THE ATALPST. BOOKS ON CHEMISTRY. PUBLISHED BY MR. VAN VOOBST, 1, PATERNOSTER Row. Especially designed for Candidates for the Matriculation Pass Examination of the University of London. By FREDERICK GUTHEIE, B.A. (Lond.), Ph.D., P.R.S.E., F.C.S., Late Professor of Chemistry and Physics, Royal College, Mauritius. HANDBOOK 02 CHEMICAL MANIPULATION. By C.GRETILLE WILLIAXS. Fully Illustrated. Post Svo, 15s. INTRODUCTION TO GENERAL, MEDICAL, AND PHARMACEUTICAL CHEMISTRY. By JOHN ATTFIELD, Ph.D., F.C.S., Professor of Practical Chemistry to the Pharmaceutical Society of Great Britain. Post 8v0, 15s. By E. FRANELAND, F.R.S., Professor of Chemistry in the Royal School of Mines. Post 8vo. Vol. 1. Inorganic, 5th thousand, 4s.THE LABORATORY GUIDE FOR STUDENTS IN AGRICULTURAL CHEMISTRY. By A. H. CHURCH, M.A., Professor of Chemistry, Royal Agricultural College, Cirencester. Post 8vo. Third edition, 6s. 6d. THE MECHANICAL THEORY OF HEAT, with its applications to the Steam- engine and to the Physical Properties of Bodies. By S. CLAUSICJS, Professor of Physics in the University of Zurich.Edited by T. ARCHER HIRST, F.B.S., Professor of Mathematics in University College, London. Will be ready shortly, price 2s., post free. T RICH. Will contain much Analytical Matter convenient for reference. THE ELEMENTS OF HEAT AND O F NON-METALLIC CHEMISTRY- Post Svo, 7s. Sixth edition, illustrated. LECTURE NOTES FOR CHEMICAL STUDENTS. Vol. 11. Organic, 2nd edition, 5s. Svo, 15s.HE ANALYSTS’ ANNUAL NOTE BOOK for 1875. Edited by SIDNEY W. May still be had, price 2s. (by post for 2s. 2d. in stamps), HE ANALYSTS’ ANNUAL NOTE BOOK for 18’74. Contains Articles on T the Testing of Anthracene, Bread, Butter, Cinchona Bark, Coffee, Milk, Mus- tard, Oils, Pepper, Soap, Tea, Wax, and many other substances. To be obtained through the post only of S. W. RICH, 23, Lloyd Square, London, W.C.JUST PUBLISHED. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS,” Vol. 1, 1876. Containing Chemical Papers read before the Society ; Original Articles ; Reports of the Society’s Neetings, &c., &c. CLOTH, 2s. 6d. BY POST, 2s. loid. ELLIOT STOCK, 62, PATERNOSTER Row. (( THE SOCIETY OF PUBLIC ANALYSTS gives in the present volume a very satisfactory account of its first year’s work.L ( It has been instrumental in introducing some improvements in an Act which would otherwise have been even less satisfactory than it is now ; it has secured very useful discussions on the general questions involved ; has produced through its members some valuable analytical papers ; and above all has led to united action among Public Analysts.6 6 The present volume gives not only the record of the actual work of the Society, including abstracts of the discussions at the meetings, but also a reprint of the recent Act, all important public papers which have been issued in regard t o it; reports of prosecutions in any respect typical, and many letters, articles, and stray notes. The Council has acted wisely in publishing the volume.”-T,aficet. ‘ 6 This book should certainly be possessed by Public Analysts.”- Chemist and Druggist. THE ANALYST. Subscription-3s. 6d. per annum, post free. Alliiterary matter to be addressed to G . W. WIGNER, 79, Great Tower Street, London, E.C. Business communications, Advertisements, &c., t o J. H. SCOTT, at the same address. Printed by ALFRED BOOT, 7, Mark Laoe, E.C., for the Proprietors; and Published by ELLIOT STOCK, 62, Paternoster Row, EX,

ISSN:0003-2654    

DOI:10.1039/AN876010035b

出版商:RSC    

年代:1876

数据来源: RSC