摘要:

Meeting of the “Society of Public Analysts” 155The Public and Public Analysts” . . 155Analysts’ Reports . . , . . 156Society of Public Analysts . . . . 167Unpublished Processes of Analysis . , 157On the Volumetric Determination of CarbonicAcid, by G. W. Wigner, F.C.S. . . 158The Detection and Estimation of Castor a i dother Oils in Balsam Copaiba, by Dr.Muter . . . . . . . 160Determination of Thein . . . . 162T. REDWOOD, PH. D., F.C.S.G. W. WIGNEB, F.C.S.A. DuPRE), PH. D., F.R.S., F.C.S.C. HEISCH, F.C.S.J. MUTER, PH. D., M.A., F.C.S.Flower of Tea , , , , , , 163Gelseminic Acid and Gelsemine . . , 164The Benzoates in Suint . . , , 164Reviews.. Volumetric Analysis, Sutton 164 ,, Water Analysis. Wanklyn dChapman . . . . , , 165Law Report. Bigsby 9. Dickinson . . 167Recent Chemical Patents . . . . 168Fines for Offences against the ( L Sale of Foodand Drugs Act” . . . . . 168Prosecutions for Adulteration in Ireland . 169A. H. ALLEN, F.C.S.J. FALCONER XING.A. WYNTEB BLYTH, M.R.C.S.OTTO HEHNER.C. A. CAMERON, M.D.E. W. T. J.ONEB, F.C.S.C. H. PIESSE, F.C.S.F. J. LLOYD, F.C.S

ISSN:0003-2654    

DOI:10.1039/AN87601FP015

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE ANALYST.Now ready, crown 8v0, 600 pap., cloth, price 12s. 6d. (postage 8d.),THE COMMERCIAL HANDBOOK OF GHEMICAL ANALYSIS;ORPRbCTICAL INSTRUCTTONS FOR THE DETERMINATION OF THE INTRINSIC OR COMMERCIAL VALUEOF SUBSTANCES USED IN MANUFACTURES, IN TRADES, AND IN THE ARTS,By A. NORMANDY,Author of iL Practical Ilztroduction to Rose’s Chemist~y,” and Editor of RoSe’s 4i Treatise on ChemicalA lzaZysis.”New Edition, Enlarged, and to a great extent re-written, by Henry M. Noad, Ph.D., F.R.S.With wmerot6s Illzcstrations.‘ 4 Will be found to be essential to the Analysts appointed under the new Act ....... In all cases the most‘ 4 In a book of nearly 500 pages, we have simple yet scientific instruction how to examine almost everyrecent results are given, and the work is well edited and carefully written.’’article of consumption.Metropolitalz.Nature.CROSBY LOCKWOOD & Co., 7, STATIONERS’ HALL COURT, LONDON, E.C.INTERESTING FACSIMILE REPRINTS,___-_ ___In crown Svo., antique binding, or paper boards, 6s. ; antique morocco, 21s. ; large paper copies, inHE COMPLEAT ANGLER ; Or, The Contemplative Man’s Recreation.roxburghe binding, 21s. ; antique morocco, 3 2 10s.By ISAACWALTON. This reprint of the first edition, published in 1653, is printed on paper similar to that ofthe original. The quaint title page, the very clever drawings of fishes, and the antique head-pieces andtail-pieces, are also faithfully copied by a photographic process, which exactly reproduces the original.ELLIOT STOCK, 62, PATERNOSTER Row, LONDON, E.C.In crown Svo., antique binding, or in paper boards, price 7s.6d. ; morocco antique, 21s. ; largepaper copies, price, in roxburghe binding, 21s.HE PILGRIM’S PROGRESS. A Reprint in Facsimile of the First Edition of 1678,The special characteristics of the first edition are carefully preserved-the colloquial language, quaintspelling, and curious side-notes, the peculiar forms and mixtures of types, the irregular use of capitals anditalics, are faithfully reproduced ; thus enabling the modern reader to rca’ise the rude form in which JohnBunyan put his immortal allegory before the readers of his own day.ELLIOT STOCK, 62, PATERNOSTER Bow, LONDON, E.C.Now ready, in small crown Svo., in antique binding or paper boards, 5s.; or in antique morocco, 21s.HE TEMPLE. Sacred Poems and Private Xjaculations. By Mr. GEORGE HERBERT, I: late Oratour of the Universitie of Cambridge. With an Introduction by the Rev. Alexander B. Grosart,Editor of ‘( George Herbert’s Works in Prose and Verse,” and of the Aldine Edition of (‘ Herbert’s Poems.')6‘ Mr. Elliot Stock has done good service to all collectors of old and curious books by publishing in hisseries of facsimile reprints, the ‘ Sacred Poems and Private Ejaculations,’ which George Herbert, the saintlyparish priest of Bemerton, bequeathed as a legacy to the Christian world, under the title of ‘The Temple.’It is only now, for the first time, that an attempt has been made t o reproduce the original work exactly asit came from the hands of Messrs.Buck and Daniels, Printers to the University of Cambridge, in 1663,the year of its Author’s death. This editio princeps has been followed exactly, not only in its contents,but in such minute details as the stopping of the volume, which is reproduced exactly the satre in type,binding, and paper, the latter being of a curious and not disagreeable brown, which looks to an inexperiencedeye at least as if it had seen the reign of Charles L”-The Times.ELLIOT STOCK, 62, PATERNOSTER Row, LONDON, E.C.IN THE PRESS,DARADISE LOST, by JOHN MILTON. A Reproduction in Facsimile of the FirstA Edition.ELLIOT STOCK, 62, PATERNOSTER Rov, LONDON, E.CTHE ANALYST.In Wrapper, 2s. 6d. On Roller and Varnished, 6s.1,\00D CHART, giving the Names, Classification, Composition, Alimentary Value, Rates of Digestibility,By R.LOCKE JOHNSON,L.R.C.P., L.R.C.S., &c.Adulterations, Tests, &c., of the Alimentary Substances in General Use.(( One of the most useful publications of the time.”-TeekZy Review.London : HARDWICKE & BOGUE, 192, Piccadilly, W.PRICE 2s. CLOTH.HE MICROSCOPICAL STRUCTURE OF CERTAIN FRUITS AND ROOTS T to be met with in the Jams and Preserves of Commerce. By ARTHUR ANOELL, F.R.M.S., PublicAnalyst, County of Hants.To be obtained of GILBERT, High Street, Southampton.LATTNER’S QUALIFATIVE AND QUANTITATIVE ANALYSIS WITH THE BLOWPIPE. P Profusely illustrated, 515 pages, ~vo., new, 1875. Published at 21s. Offered for a short time at Gs. 6d.LETHBBY on Noxious Trades, 1s. post free.LETREBY on the Right Use of Disinfectants, 1s. post free.Milk in health and disease, by A. HUTCHINEON SMEE.London : HENRY EIBIPTON, Medical Publisher and Bookseller, 82, High Holborn.Circulating Library, 21s. per annum. List of Works on Chemistry, &c., gratis.Ready, pp. iv. and 78, price 2s. post free.HE ANALYSTS’ ANNUAL NOTE BOOK for 1875. Edited by SIDNEY-W. T RICH, Contains the principal part of the Analytical matter of the year in a partially condensed form.To be obtained through the Post only of S. W. RICH, 23, Lloyd Square, London, W.C.I n the Press and will shortly be published a revised and fuller Edition ofUTTER; ITS ANALYSIS AND ADULTERATION. By OTTO HEHNER B and ARTHUR ANGELL, Public Analysts.“ PROCEEDINQS OF THE SOCIETY OF PUBLIC ANALYSTS,’)Vol.1, 1876.(‘ THE SOCIETY OF PUBLIC ANALYSTS gives in the present volume a very satisfactoryaccount of its first year’s work.(( It has been instrumental in introducing some improvements in an Act which wouldotherwise have been even less satisfactory than it is now ; it has secured very usef‘bidiscussions on the general questions involved ; has produced through its members somevaluable analytical papers ; and above all has led t o united action among Public Analysts.‘( 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 recentAct, all important public papers which have been issued in regard to it; reports ofprorecutions in any respect typical, and many letters, articles, and stray notes. TheCouncil has acted wisely in publishing the volume.”-Lancet.This book should certainly be possessed by Public Analysts.”- Chemist and Druggist.( I This is rather more than it purports to be, since it contains a number of paragraphsand leading articles.”( 6 Many valuable papers are reprinted, and the book is not only practically useful,but also is an indication of healthiness and earnestness on the part of one of theyoungest of our scientific societies.”--li.olz.THE ANALYST.Subscription-3s. 6d. per annum, post free.A11 literary matter to be addressed to G . W. W~GNER, 79, Great Tower Street, London, E.C.Business communications, Advertisements, &c., to J. H. SCOTT, at the same address.Printed by ALFRED BOOT, 7, Mark Lane, E.C., for the Proprietors ; andPublished by ELLIOT STOCK, 62, Paternoster Row, E.C

ISSN:0003-2654    

DOI:10.1039/AN87601BP017

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE PUBLIC, AND ‘(PUBLIC ANALYSTS.” THAT muc.h ignorance exists in the public mind with respect to the real function of ‘( The Public Analyst” under the ‘ I Salc of Food and Drugs Act,” is evident from the paragraphs which from time to time appear in different journals, and which could only be justified, were it the analyst’s duty t o procure samples, institute prosecutions, and indeed insure convictions, as well as to make analyses.Thus, we are told that in a certain place, the rate-payers are being made to pay for nothing, as the analyst confesses in his quarterly report, that he has not analyzed a single sample, or again, that the analyst’s report was read with the usual result, viz., that everything he had examined was found to be genuine ! ! ! &c. Not only so, but if an analyst meets any of the inhabitants of his district he is pretty sure t o be saluted with the inquiry, “ what are you about, you prosecute no one? while t o my knowledge, the diatrict is full of adulterated food.” With a view to dissipate the misapprehension which underlies these remarks, we propose not only to state--what everyone might know for himself-that the analyst has nothing t o do but t o examine samples that me brought to Izim; but also to point out the difficulties which often lie in the way of his procuring such samples, as would give anything like a fair idea, of the articles sold in the district. There are some Vestries and District Boards, which show onlF too clearly that they have no desire that the fact that adulterated articles are to be found in their parish should be published, The inspector soon takes his cue from his superiors and purchases articles where there is uo chance of obtaining any that are not pure, and the vestrymen, when the analyst’s report is read, stating that everything he has examined during the quarter was genuine, exclaim with one voice c L how vcry satisfactory ! ”156 THE ANALYST.A much more frequent cause of difficulty in procuring fairly representative samples is the jealousy which Boards feel of anything being procured without their express order.At a meeting of the Board a resolution is passed that “the Inspector be ordered to procure so many samples of such an article, and submit them to the Analyst.” This is published in the local paper next morning, and it is not surprising that after this kindly warning only pure samples of the article in question are sold in the district (except by accident) till the specified number is known to have been bought.The fact that the Inspector is always well known to the shopkeepers in his district is also a great hindrance to his procuring samples of inferior quality, and if he be not a man of resource, with a good deal of the spirit of a detective in him, he mill rarely succeed in doing so. But, perhaps, the worst feature of the case is that the public who complain (often, we believe, without cause) of the food siipplied to them, and of the Analyst for not making it txtter, will not move a finger to help themselves.Under the older Adultera- tion Act, when the local authority had power t o prosecute the vendor of an article brmght for analysis by a private individual, and to suU6pma that individual t o prove the purchase, scarcely an article was so brought, or if brought, was often taken away again as soon as the purchaser became aware of the fact that if it was found to be as he suspected, he would have to give evidence in a Police Court.Under the present Act, where the purchaser may (if he will) become the prosecutor, but need not unless he likes, the Analyst is often called on to make analyses not really for any public good, but merely to satisfy the mind of the purchaser, and if the Analyst ventures to hint to him that the intention of the Act is to put a stop to adulteration by punishing those who are guilty of it, and that, therefore, he ought to prosecute the vendor, if the certificate of analysis justifies such a course, he generally replies, L L Oh ! I could not go into a Police Court ; of course, I shall not deal at that shop any more.” We are convinced that more good would be done to honest tradesmen, and the intention of the ‘‘ Sale of Food and Drugs Act ’’ be better carried out if, for a short time, the public, or even a few individuals, would make up their minds not only to have suspected articles analysed, but to take the trouble of prosecuting if they were found impure.We may here remark that a doubt exists in some people’s minds whether, if they purchase an article, and when they begin to use it have reason to believe it impure, they can have it analysed under the Act, as they cannot give the vendor the option of keeping a sample of the article.We have good legal advice that they can do so, the clause requiring articles to be divided relating only t o those bought ‘‘ with the intention of submitting the same to analysis,” which clause does not take away the power granted by clause 12 to any purchaser of any article of food or drink to have it analysed if he wishes. I f this opinion be correct, of which we have little doubt, it takes away the only excuse the public really hwe for not doing their share in carrying out the Sale of Food and Drugs Act,” and me can promise them that if they will awake t o a sense of their duty, every aid will be given them by the much abused Public Analysts.

ISSN:0003-2654    

DOI:10.1039/AN876010155b

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

156 THE ANALYST. AXALP ST S’ REPORTS. TEE report of Dr. Duprd, analyst for the Westminster district, for the quarter ending September 29, just issued, states :-“ During the quarter just elapsed twenty-four samples of articles of food have been examined, namely :-Of bread, 9 samples ; milk, 15. The results of the examinations, I am happy to be able to report, have been very satisfactory. All the samples of bread were found to be pure wheat bread, free from alum or other foreign admixture.” The annual report of Dr.Corfield, analyst to the parish of St. George’s, Hanover-square, states that of five samples of butter examined, three were found to be genuine, one poor, and one largely adulterated with foreign fats, and a certificate to that effect was given to the purchaser. Of eight samples of tea analysed, five were genuine, two fairly good, and one contained exhausted leaves. Of four samples of vinegar got to obtain information, three were genuine and one adulterated with sulphuric acid

ISSN:0003-2654    

DOI:10.1039/AN8760100156

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE ANALYST. 157 UNPUBLISHED PROCESSES OF ANALYSIS. After, and to a great extent, in consequence of, the passing of the Act of 1872, for the prevention of adulteration, a great imyetus was given to analytical work. Hany articles of food and drugs which had previously only been analysed as curiosities came to be carefully examined for the purposes of the Act, and processes were worked out with care, for the detection of any impurities or adulterations which might be present.Some few of these processes were published; but until the formation of “The Society of Public Analysts,” chemists, as a rule, worked according to their own individually acquired knowledge, there being no authenticated collection of those pro- cesse8 which had been found successful. ‘( The Society of Public Analysts ” took the first step in this direction, and by the reading, discussion, and publication of papers, gradually familiarised its members with a number of processes which had been carefully worked out and their accuracy tested.By these means public analysts have so far adopted a uniform system of work, and made a uniform allowance (necessarily an excessive one) for the natural impurities and variations of samples, that it is now quite the exception to have an analysis disputed.So far, no doubt, the Society deserves credit, and any one who examines the first volume of its (‘ Proceedings,” will find that no previous work has contained so much information on food analysis. The AnaZylst has endeavoured to continue this work, and has published the description of numerous processes for the analysis of many commercial samples other than articles of food, but an examination of the authorship of these articles, as well as of those which hare appeared in our scientific contemporaries, clearly bring out the fact that the greater part are contributed by a very limited number of chemists.There are, probably, at least two hundred individuals who fairly deserve to be des- cribed as “ analysts,” and yet we are of opinion that not one fourth of them have ever contributed any number of analyses of different varieties of some known substance, still less the descriptions of any new processes. We do not, by any means, intend t o limit our remarks to food analysis; but leaving out that class of original work which consists in the discovery of previously unknown substances (highly essential though this is), we believe that not fifty chemists in England have, during the last five years, contributed anything which can be considered really in advance of the aualytical methods previously i n use ; and some of what it is the fashion to call ‘‘ leading chemists,” have done absolutely nothing.I f analytical chemistry is to take its proper rank as a profession, this must be changed. Analysts, young and old, must make public the results of their work, and the columns of scientific journals must show not ody descriptions of many processes, but the names of many discoverers of the saae. It is not giten to every one t o be a Davy, or a Faraday, but every chemist who honestly works, can contribute t o the common fund sonasthing, which shall at least have the merit of being alike original aud accurate.

ISSN:0003-2654    

DOI:10.1039/AN876010157b

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

158 THE ANALYST. ON THE VOLUMETRIC DETERHINATION OF CARBOPU’IC ACID, BY G. W. WIGNEB, F.C.S., Read before the Society of Public Analysts, Novena6er 15, 18’76. I have used for some time a very simple apparatus for the volumetric determination (in a gaseous state) of the combined Carbornic Acid, in Carbonates. Schiebler’s apparatus is, of course, only adapted for those carbonates which produce salts with Hydrochloric or Nitric Acid, which ire readily soluble in cold water, and although it is an extremely handy instrument, it is open to several objections, the principal of which are- That the temperature of the evolved carbonic acid gas, requires to be carefully taken, and this can only be done by taking the temperature of the external air, and allowing the instrument to rest, until the evolved gas has acquired this temperature, and That the acid solution used to decompose the carbolzates, absorbs a proportion, and (according to my experiments) an irregular amount of Carbonic Acid, and finally the scale of the instruments is purely empirical.Most laboratories are now furnished with the McLeod apparatus, or with some similar efficient apparatus for measuring the volume of gases under known conditions of temperature and pressure, and I have therefore devised a simple apparatus for the decomposition of carbonates, and the measure- ment of the gas evolved.I take a test tube of about 7 inches by 1 inch, and provide it with a good India rubber stopper, bored with two holes. Through one of these holes I pass a tubulated thistle-headed funnel of small size, furnished with a stop-cock, and through the other a bent piece of small bore glass tubing, also provided with a stopcock.This bent tube is coupled t o the McLeod, or other gas measurement apparatus, by a short length, (say 6 inches) of very stout, small bore, India rubber tube, 1-16in. is large enough for the bore of this. I n the bowl of the thistle funnel, I put a glass marble, and in the interior of the test tube, a smaller test tube of about 2in. + Q, containing the sample t o be analysed.The apparatus is shown complete in the accompanying sketch. The process is as follows :- The tubes of the McLeod apparatus are filled with mercury, as if for an ordinary gas analysis, and the stopcocks closed. The sample, (say 25 grains of carbonate of lead) is weighed and transferred to the smallest tube, and about half-an-ounce of distilled water is poured into the large test tube.The small tube is then carefully dropped in, taking care that its mouth is above the love1 of the water in theTHE ANALYST. 159 large tube; the stopper, into which the funnel and bent tube hare been inserted is then carefully put in place, and the whole held in a slightly oblique position in a retort stand clamp, on the ordinary rising table of the McLeod apparatus ; the India rubber tube is then coupled up to the facets of the measuring tube of the McLeod apparatus.I f the stopcocks on the bent tube, and on the funnel are opened for a moment, any excess of air in the India rubber tube is liberated.The stopcock on the bent tube is now closed, and the mercury in the measuring tube of the McLeod apparatus allowed to fall, so as t o produce a vacuum. The stopcock on the funnel remains open, and a lamp is applied t o the bottom of the test tube, until the water boils briskly when distilled water is poured into the funnel and kept from running into the test tube by the pressure of steam generated by the ebullition of the water; the boiling is continued until the steam escaping through the funnel and under the glass marble, aZZ condenses, showing that the tube is filled with pure steam. The lamp is now withdrawn, and the stopcock instantly closed.Thisis not difficult, as it is three or four seconds before the water in the funnel begins to draw back. Meanwhile, a portion of dilute nitric acid has been boiled on another burner, and is poured into the funnel.I prefer not t o use much more than is necessary for the libera- t o r of the carbonic acid present. The stopcock on the bent tube, and the stopcock on the measuring tube of the McLeod apparatas are opened, and then the stopcock on the funnel is cautiously opened. The hot acid, of course, immediately runs in, and the only pre- caution necessary, is to avoid liberating the gas too quickly.When the test tube is about two-thirds full and all effervescence has ceassd I again boil the solution in the tube, and then, still maintaining a partial vacuum, by means of the mercury, fill the tube coiiyietety, through the funnel with 6oiZing distilled water, until every bubble of air is driven into the measuring tube of the McLeod.The stopcock on the bent tube is then shut and the mercury in the pressure tube and the measuring tube of the McLeod brought to the same level. This brings the internal pressure of the air on the short india rubber connecting tube t o the atmos- pheric pressure, and as itsvolume does not exceed 1c.c. the correction for its temperature may be safely omitted.The gas is then measured in the ordinary way, and its volume calculated t o weight and per centage. I find that it is easy to make four determinations of carbonic acid per hour by this apparatus, and the accuracy of the results is very great. The following are repeat analyses of commercial white lead, taken at random from some hundreds which I have tabulated, and fairly represent the character of the results, since they include the errors incident to determination of temperature, and barometric pressure, as well as those of mere manipulations in the apparatus.On 25 grains 1st d-tcrmination CO, ................................. 12.222 per cent. in each case. 2nd ,) ,) ................................ 12.274 ,, 2nd 7, ,) ................................. 13.867 ,, 1st ), ................................. 13 322 ,, 2nd :: ,) ...............................13.334 ,, 7 ) ,, ................................. 13,228 ,, 1st 2nd 7 9 ,) ................................. 13.212 ,, 7, ,, ................................ 11'707 ,, 1st 2nd ,> ,, ................................. 11,703 ,, 1st ................................. 13,836 ,, ,? ,, I n 6 determinations in different weights of calc. spar. the results varied from 43.83 per cent., t o 43-92 per cent., as against 44 per cent. theoretical. Assuming the cnlc. spar. t o have been absolutely pure, the loss of carbonic acid only amounted to an average of 10 per cent., 5 grains being about the average quantity used for the analysis.

ISSN:0003-2654    

DOI:10.1039/AN8760100158

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

I60 THE ANALYST. A METHOD OF DETECTING AND ESTIMATING CASTOR AND OTHER FIXED OILS IN BALSAM COPAIBA. Read before the Society of Public Analysts, November 15th, 1876. BY DR. MUTER, THIS oleo-resin, commonly but wrongly termed a balsam, has been said in booksformany years back, t o be subject t o admixture with fixed oils, especially castor oil. The British Pharmaco~ceia furnishes a qualitative method of examination, but the tests are, in practice, totally insufficient, as the exact degree of rectification of the benzole (an important point) is not stated, and the difference between a pure balsam stain and that with a small percentage of oil is very slight, unless the two are observed side by side. The other methods which have been proposed may be summarised as follows :- 1.Pure balsam gives a translucent and not an opaque emulsion, with strong 2. Pure balsam, if boiled with water for some hours, leaves a tenacious resin. 3. The specific gravity. The latter test is entirely failacious, owing t o the great variation in commercial samples, and the others, though possibly characteristic with large admixturee, fail with anything under 20 per cent.Observing the close affinity between copaivic and pinic acids, it struck me that advantage might be taken of the difference of solubilitr of the sodium soaps in certain menstrua. A very good solvent for sodium pinate has been discovered by M. Barfoed to be a mixture of five parts by volume of absohte ether, and one part absolute alcohol, which, moreover, only dissolves sodium oleate t o an exact extent corresponding to 1 in 1,000 of oleic acid.I will not occupy space by detailing at length the numerous experiments on a great number of samples of balsam, varying in age and colour from every known commercial source, but the whole thing ended in the certain conclusion that besides the essential oil (which is dissipated in the process of analysis) good commercial balsam contains only copaivic acid, which forms a sodium salt, instantly soluble in the ether-alcohol mixture, and a little altered resin not so readily saponifiable, forming a salt only slowly soluble.The amount of this second resin I have found to vary dightly, and, in very old samples, especially of Maranham balsam may sometimes amount t o five per cent., although psually really less.Going upon the principle that performing any official analysis the lowest commercial standard should be taken, I have adopted six per cent. as the highest possible quantity of the second resin ever existing in any sample of balsam still having a trace of odour remaining. This wide standard may sometimes lead t o an under estimation of the oil by two or three per cent., but renders any over estimation impossible. The actual process I employ is as follows : 3 t o 4 grammes of the sample are weighed into a clean dry flask, and saponified on the water bath with 50 C.C.of alcohol and lump of caustic soda, weighing not less than 5 grammes. When all is dissolved water is added, and the whole washed into a half-pint basin so as to nearly fill it, and evaporated to 100 C.C.over a low gas flame. Dilute sulphuric acid is then added till the whole just becomes permanently turbid, and then solution of caustic soda is dropped in till it just clews again. By this means a solution is obtained with the least possible excess of alkali, and with a good amount of sodium sulphate. The whole is now evaporated t o perfect &ynessg on the water bath, stirring towards the end, so that the sulphate may mix with the soaps and produce an easily pulverulent residue. The residue is removed from the basin into a small wide-mouthed stoppered bottle, and treated with 70’ C.C.of solution of ammonia. * The best way to ensure absolute dryness is to moisten the apparently dry residue with a fe1-V drops of absolute aloohol and again dry.THE ANALYST.161 ether-alcohol, and well shaken up. As soon as it is fairly settled the fluid is filtered off through a quick filter, and this is repeated with two successive quantities of 70 c.c., making 210 C.C. in dl of the solvent used. The residue in the bottle and on the filter now consists of sodium oleate and sulphate if the balsam be impure, and of the latter only if pure, with a little trace of the insoluble resin soap already referred to.The contents of the bottle and filter me then dissolved in warm water, aod after heating until all smell of ether is gone, the whole is boiled, freely acidulated with hydrochloric acid, and set t o cool. If, when cold, nothing but a few specks of brown resin should rise to the surface, the balsam is pure, but if an oily layer be formed, it is adulterated, and the smell of the separated oleic acid will at once determine whether it is actually castor oil or not.I n the case of the presence of oil, two grammes of pure and dry white wax are added, and the whole heated till the wax melts with the oleic acid. On cooling, a solid cake is formed, which is detached from the side of the beaker, and the fluid below passed through a filter.The cake is once more melted in boiling water, cooled, detached, dried- by gentlo pressure in blotting paper, put into the water oven in a weighed platinum dish till dry, and then weighed, aqd the weight of the wax used deducted. The beaker, filter and rod, &c., used are, if at all dirty? dried, extracted with ether, and the residue, left after evaporation, weighed and added to the total.The calculaticn is then performed as follows :- 1. To the weight in grammes found, add -20 for loss of oleic acid i n solvent, and then say as 95 : 100 :: total oleic acid. 2. Calculate t o per cent. from the quantity taken, and from the total percentage Out of the whole number of samples I have done, I have selected the following twelve, as being fair representations of the degree of accuracy obtainable by the process.The error, owing to the correction, of course increases with the amount of oil present, but it is always an error in the direction of under estimation, which is the great point for public analysts. deduct six per cent. for possible altered resin in the balsam. Nature of Sample.Calculated. Para (pale) . . . . . . . . . . . . Pure . . . . . . . . . . . . Para (pale) . . . . . . . . . . . . 23.60 per cent. castor . . . . . . Old Para (dark) . . . . . . . . . 51.0 per cent. castor . . . . . . Carthage (medium) . . . . . . 21.5 per cent. castor . . . . . . Maranham (pale1 26.5 per cent. castor . . . . . . Old Maranham ( d a r k h veiiiittle o'dour) Pure .. . . . . . . . . . . Para (fine pale) . . . . . . . . . Pure . . . . . . . . . . . . Para (fine pale) . . . . . . . . . 21.4 per cent. lard oil . . . . . . Old Para (dark) . . . . . . . . . Pure . . . . . . . . . . . . Carthage (medium) . . . . . . Pure . . . . . . . . . . . . Maranham (pale . . . . . . . . . . Pure . . . . . . . . . . . . Old Maranham ( ,, ,, ) 47.3 per cent.castor ... ;.. Found. No oil drops. 23.50 No oil drops. 504 per cent. No oil drops. 21-20 No oil drops. 26-27 No oil drops. 46.4 No oil drops. 20.9 I n conclusion, I may say, that the process, although it looks formidable, is in practice very simple, and for all ordinary purposes, if the beaker be well scraped out, the weight of the main cake, may be taken as sufficient to give an analysis true within 3 per cent. below the real amount, which is accurate enough for public purposes, and gave8 time and the expense of the extra ether.Unless oil actually floats and remains on cooling in $%id drops, after adding the hydrochloric acid, the sample may bo passed as good.162 THE ANALYST. When working on 3 to 4 grammes, with an admixture of not over 25 per cent., the errors due to loss of oleic acid and insoluble resin soap respectively so nearly balance each other, than any correction is unnecessary, and the actual amount af oleic acid found may be taken as correct within a per cent.Mr. Hehner stated, that he had experience of darfoed’s process for the analysis of resin aoaps, and had found it successful, and he had no doubt that if copaiba behaved like resin the process would be reliable.Dr. Bartlett, thought it a very good process, so long as no other foreign substance was present, but feared that the presence of boric acid might be found to interfere seriously with its accuracy, as he had sometimes found t o be the case in soap analysis. Dr. DuprB, inquired whether the testing of the ethereal solution would give any data for estimating the proportion of added resin (if any). Dr. Muter, in reply, said he had not yet tested the ethereal solution for resin, so as ascertain if any had been added, but Dr. Dupr6 must remember, that it is the detection of oil only that the process aimed at, resin being qn extremely improbable addition, as it would spoil the balsam. The instructions in the P.B., were comparatively worthless; while in the new process, if the oil actually did separate, there was proof positive of adulteration. As t o Dr. Bartlett’s objection, although borax sometimes occurred in soap, it never existed in balsam copaiba, nor could it be added to that substance without emulsifying it.

ISSN:0003-2654    

DOI:10.1039/AN8760100160

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

162 THE ANALYST. DETERMINATION OF THEIN. Berichte des Beutschen Chemisehen Gesellschaft xu Berlin, 1876. CORRESPONDENCE FROM ST. PETERSBURG. [Meetings of the Russian Chemical Society on the 6th and 18th May.] HERR BUTLEROW (for Herr Markownikoff), reports on the determination of thein in tea. Since the methods hitherto adopted yield unsatisfactory results, partly because they leave out of consideration the peculiarities of the combinations in which thein exists in the tea-leaf, and partly because they are inconvenient ; the author proposes the following :- 15 grams of powdered tea are covered with 500 C.C.water, and then, 15 grams burnt magnesia being added for each 5 grams (tea?), rapidly heated to boiling. The liquid is then atered, tho precipitate washed with hot water, and the filtrate evaporated to dryness, with addition of a little-magnesia and sand.The thein is extracted from the residue with hot benzol (in a special apparatus, not described), the latter distilled off on the water bath, and after every trace of it has been removed by a gentle current of air, (from a 6lowing-6ag,) the thein is weighed. I n the opinion of the author, the want of strict accuracy in the method is due t o the possible volatilization of a small quantity of thein, with the benzol vapour.His experiments prove, that the quantity of inorganic constituents, which remain as ash, decreases as that of the thein increases. Since, however, the better sorts of tea are made from younger leaves than the poorer, relatively more thein is contained in the young leaf than in the old. Herr Markownikoff is, moreover, of opinion, that the value of tea is determined, not by its thein, but by t'annic acid, ethereal oils, and other constituents. No. 14. Page 13 12. C. A. C.

ISSN:0003-2654    

DOI:10.1039/AN8760100162

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE -4NALPST. 163 FLOWER OF TEA; OR, PEKOE FLOWER. By T. B. GROVES, F.C.S. Phwm. Journal, [3], 327, p . 285. IT appears from Mr. Groves’ paper, that 100 lbs. of a substance bearing the above appellation, was received at the Weymouth Custom House for export to Jersey. A portion of it was Bent to the London Custom House for report, and an answer wa8 returned that the article was really tea, that it was not the leaf of the plant, but the pollen of its flower.On microscopical examination, it was at once seen not t o be the pollen of the tea flower, or, any other flower: but to be composed of simple uncellular vegetable hairs, mixed with small fragments of tea leaves, together with sand and probably other extraneous substances. These hairs, by the assistance of Mr. Holmes, were established t o be really the hair of the leaf-buds of the tea plant, and the sample was then handed to Mr.Wiper, i n order to ascertain its chemical composition. Mr. Wiper’s report, is as follows :- Analyses of Tea marked Pekoe Flower. per cent. Ash soluble in Water . . . . . . . . . . . . 1.15 Ash soluble in Acid . . . . . . . . . . . . 4.54 Silicious matter . . . .. . . . . . . . 1 3 . 04 Total Ash ...... 18-73 Moisture . . . . . . . . . . . . . . . 7.00 Extract (soluble in water) . . . . . . . . . 14-65 Ash of ditto . . . . . . . . . . . . . . . 2.40 Theine . . . . . . . . . . . . . . . 1.50 Tannin (Pb. process) . . . . . . . . . . . . 12.00 - i The composition of the ash, was as follows :- Oxide of Iron . . . . . . . . . . . . . . . Lime .. . . . . . . . . . . . . . . . . Magnesia . . . . . . . . . . . . . . Potash and traces of soda . . . . . . . . . Oxide of Manganese . . . . . . . . . . . . Sulphuric acid . . . . . . . . . . . . . . . Carbonic acid . . . . . . . . . . . . . . . Chlorine.. . . . . . . . . . . . . . . . . Phosphoric acid.. . . . . . . . . . . . . . Silica . . . . . . . . . . . . . . . . . . Loss in analysis .. . . . . . . . . . . . . . 6-01 4.83 2-05 4.93 1-02 1-29 7.39 0.61 5.33 66.18 *32 100*00 - ... ... ... ... ... ... ... ... ... ... ... ... ... ..* The average Analyses of Pekoe. per cent. ... 3-30 ... 2-60 ... .30 6.20 ... 7.30 ... 34.00 ... 5-00 ... 3.50 ... 28 00 - - - ... 6-00 ... 11.00 ... 32.50 ... 4+0 ... 12.00 ... 16.00 ‘‘ I have made several unsuccessful attempts to sift the sample. A large portion of the hair haa passed through with the dust. The gross ash yielded by the sifted part corresponded tolerably with that of the original saaple. The microscope shows much leaf in fragments, and so9e of these fragments certainly appear to belong t o some plant, which is not tea.” A. w. B.

ISSN:0003-2654    

DOI:10.1039/AN8760100163

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

164 THE ANALYST. ‘‘ GELSEMINIC ACID ” AND GELSEiUINE. ~’KOFESBOR SONNENSCHEIN (Berichte, des deutschen chem. Gessellschaft, jahr ix. Sep. 18. p. 1182) has apparently established the identity of Wormley’s “ Gelseminic Acid,” obtained from Gelseminum Xemper- Pirens, with tesculin H34 019. Gelsemine is obtained by treating the alcoholic extract of the root after separation of the resin with basic acetats of lead, filtering, then removing the lead by sulphuretted hydrogen from the filtrate, shaking with ether, and adding potash t o an alkaline re-action.The light flocculent precipitate is collected, and purified by redissolving in hydrochloric acid, again precipitating by potash and shaking up with ether. On removing the ether and evaporating it down, Gelsemine is left as an amorphous, almost colourless, alkaline, bitter powder.Gelsemine melts under 100°C t o a colourless liquid, at higher temperatures, it is decomposed ; it is freely soluble in ether and chloroform, somewhat soluble in alcohol, but not very soluble in water. Gelsemine neutralizes acids, but as yet no crystallisable salts have been formed. The chloride is readily soluble in water, and gives precipitates with chloride of gold, iodine in iodide of potassium, potassio mercuric iodide, and platinic chloride.The best test for the presence of gelsemine is thc bright light cherry red colour, which a small portion exhibits, if dissolved in concentrated sulphuric acid, to which 8 amall portion of ceroso-ceric oxide has been added. The formula of gelsemine appears to be CII HIS N02.A. W. B. TEE BENZOATES IN SUINT. BY ANDREW TAYLOR, F.C.S. Pharmaceut. Journal. [3] No. 327, p . 272. MR. ANDREW TAYLOR has made some experiments with regard t o the extraction of Benzoic Acid from Xuint, he distilled in an 80-gallon steam. jacketed still, working a t a pressure of 20-lbs. to the square inch, equal parts of petroleum spirit and suint, until a ton of the latter had been operated upon.A yellow fatty liquid of sp. gr. 1.2 was by this means obtained, which gave characteristic tests for benzoic and hydrocyanic acids. Xight gallons of this liquid were mixed with about a gallon of hydrochloric acid, and heated in a steam jacket for about an hour and a half, there was a copious evolution of ammoniacal and other fumes, and the residue consisted of a brown liquid rich in benzoic acid.From this $-of a pound of benzoic acid was obtained, or nearly three pounds to the ton of suint. A. W. B. REVIEWS O F BOOKS, &c. A SYSTEMATIC HANDBOOK OF VOLUMETRIC ANALYSIS. By FRANCIS SUTTON, F.C.S., &c., &c. London, J & A. CHURCHILL, 1876. THIS is a third edition of this useful work, which has, as the preface states, been out of print for nearly two years.The author specially acknowledges the valuable aid he has received from Mr. Thorp and Professor McLeod, and points out that the latter has, ( ( with characteristic modesty,” said but little about his own special improvements in the apparatus for gas analysis. We find a confirmation of this statement in the fact that we do not discover any reference t o the last new form of ‘( facet ” which Professor McLeodTHE ANALYST.165 has devised for his gas analysis apparatus, which though. a small improvement, is one certain to be appreciated by all who are in the habit of using the apparatus. The preRent edition contains about 50 pages of new matter, some 15 pages of which relate to the analysis of water.Among the additions, we n3tice the colorimetric processes for the estimation of iron and copper, which are rightly included in such a work. Volumetric processes are also introduced for the determination of nickel, cobalt, bismuth, cadmium, uranium, arsenic and bromine. We have not yet been able to form an opinion on these processes, from actual experiments, but they appear to be useful additions to the work.The processes for the determination of zinc and manganese appear to be revised and judiciously extended. The book appears fairly free from errata, but there are two of such importance, that they need a notice here. On page 86 in the description of the indirect process for the estimation of potash and soda, a factor is stated as’ 0.36288, whereas, if we adopt the equivalents used in the book, namely, Na=23, K=39, this factor mill be 3.6562, (or more than ten times as high as quoted.) The mistake is evidently a double one, arising from the misplacing of a decimal point, and the mis-calculation of the factor.The key to the mis-calculation is found on page 330, where, however, the directions fQr the calculation are again in error. An alteration in the mode of setting the type in the description of the details of the processes, certainly adds to the convenience of the work as a book of reference.The extra matter (some 15 pages) introduced with reference t o the Frankland ‘and Arm- strong water process will also be valued by those chemists who adopt that mode of analysis ; but we cannot. avoid an expression of regret that the much more serviceable process devised by Messrs.Wanklyn, Chapman & Smith, is passed over with only some half dozen pages. This is the more unfortunate, since we believe we are quite safe in assuming that the latter process is at least ten times a8 much used as the former. We notice that, under the head of Sugar, our author omits all reference to Polarization, we presume, because it would hardly come within the title of volumetric analysis.Yet all who are in the habit of analysing sugars daily, know Tell that no other method can be depended on to give results, within two or three per cent. The processes for Tannin determination are considerably enlarged and improved, and the same remarks mill apply to the determination of urea, phosphoric acid, and zinc.On the whole, the new edition is unquestionably of greater value than its predecessors, and certainly forms by far the most complete resumk in the English language of volumetric processes of analysis, and very few such processes, which have any pretensions to accuracy are omitted. We must not forget t o mention one great point in the author’s favour, namely, the extreme care which has been taken to acknowledge the source, from which the processes have been derived.WATER ANALYSIS : A PRACTICAL TREATISE ON THE EXAMINATION OF POTABLE WATER. By J. ALFRED WANELYN, AND ERNEST THEOPHRON CHAPKAN. [Fonsrlr EDITION.-~ewr&en 6y 3. ALFJXED -\NANELYN, M.R.C.S., $c., $c. London: TRUBNER & Co. THIS Edition of the above treatise, has been enlarged and improved in various directions.The work is now divided into three parts : the first part gives direction for “ Water Analysis for General Sanitary Purposes ;” part two, treats of ‘( Special Analysis, &c.;” and part three, gives ‘‘ Examples of Complete Mineral Analyses.” The directions given are, for the most part, precise and to the point, and we can confidently recommend the little woik to all rcquiring a guide t o thc aaaljsis G f water.166 THE ANALYST.The albuminoid ammonia process, which is the back-bone of the work, has in the course of the last eight years, worked its way into very general use. This cannot, we think, be attributed entirely, or evcn mainly, to its exceeding simplicity, as some of its opponents allege, but is, we believe, due chiefly to the conviction becoming more and more general among water analysts, that its indications taken in conjunction with a few other constituents of the water, are amply sufficient to guide them t o a correct conclusion.I n part, however, it must be ascribed to the very complete way in which the process has been placed before chemists by its inventors. Thus we know, for certain, that the presence of even considerable proportions of ammonia, or of nitric acid, is absolutely without influence on the estimation of the albuminoid ammonia, We know also the behaviour of a great variety of nitrogenized substances, when submitted t o the process. There is, therefore, a great body of experimental evidence, showing what the albuminoid ammonia process is, or is not, capable of accomplishing.It is far otherwise, with the rival process of Professors F.rankland and Armstrong. Many thousand analyses have been made in Prof. Frankland’s laboratory, by means of this process, but as far as we know, not a single experiment has been made, certainly not one has been published, which really demonstrates in a satisfactory manner, the soundness of the method as applied t o the analysis of water.Most chemists are, we believe, convinced that, assuming the organic matter to be once inside the combustion tube free from an admixture of nitrates, its carbon and nitrogen can be estimated with an extraordinary degree of accuracy, by means of Frankland and Armstrong’s process. The real questions, however, are, firstly : does the process enable us t o get the organic matter dissolved in a litre of water into our combustion tube undiminished in quantity, and freed from the large excess of nitrates, with which it is often associated, and secondly, can we make accurate allowance for any ammonia which mag.be present in the water ? None of the published experiments prove these absolutely vital points, and we venture t o affirm, that until Dr.Frankland, or some other chemist, supplies this necessary experimental evidence, the combustion process will find but few adherents. But while thus strongly recommending Mr. Wanklyn’s work, we would not be understood as endorsing everything the author advances, for he has committed many sins, both of omission and commission. Thus we believe that Mr.Wanklyn seriously, and most injudiciously, under-estimates the importance t o be attached to the presence of nitrates in water, and the same may be said regarding phosphoric acid. The chapler on gases dissolved by water, is most meagre, none of the newer processes for their estima- tion being given. A special chapter is given to iodates, bromates and chlorates, the latter of which have never yet been found in a natural water, while nitrous acid is only once incidentally mentioned, and no test is given for its recognition, and sulphuretted hydrogen is not even alluded to. Very little information is given respecting the presence of the alkaline chlorides, nothing whatever for example is said regarding the conclusions to be drawn in case either the potassium or sodium chloride is found t o predominate. These and like defects, we hope to see made good in the next edition, which, we doubt not, will soon be called for. I n conclusion, we must express our deep regret, that Mr. Wanklyn has introduced controversial matter into the pages of his work ; such matter is wholly out of place in a treatise, and when put‘ forward in the manner in which it is here done, it constitutes ti very serious blemish in an otherwise most meritorious work.

ISSN:0003-2654    

DOI:10.1039/AN876010164b

出版商:RSC    

年代:1876

数据来源: RSC