摘要:

Meeting of the Society of Public Analysts . 119 Ion ditto . . . . . . 120On Enamelled Cooking Vessels, by R. R.Tatlock, F.R.S.E., etc., and discussionCorrespondence-Letter from Dr. Muter . 122Note in reference to Mr. Rich 122 Y ? I W i p e r , F.C.S., and R. H. Harland,F.C.S., and discussion on ditto . . 123On the Fraudulent Colouration of Wines . 130Prosecutions under the “Sale of Food andDrugs Act”. . . . . . 136J. FALCONER KING.A. WYNTE~ BLYTH, M.R.C.S.OTTO HEHNER.C. A. CAMERON, M.D.E. W. T. JONES, F.C.S.C. H. PIESSE, F.C.S.F. J. LLOYD, F.C.8

ISSN:0003-2654    

DOI:10.1039/AN87601FP003

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE ANALYST.BALANCE.To carry 20 grammes in each pan. .. 12 Guineas>, 200 7 7 9 , 14 9 997 500 7, Y 9 18 9 99 , 1000 9 9 Y, 25 9 9WOLTERS’ BALANCES.GRAMME WEIGHTS (in Mahogany Boxes).From 10 grammes to 1 milligramme 1+ Guineas9 , 100 7 1 J , 2 9 9 ,9 , 200 9 , , Y 2; 9 97, 500 9, 7, 3 9THE ANALYST.case is very different with the beam; here the number of vibrations in a given time augment in theratio of the squares as the beam shortens, so that a beam one-third the length of another would performnine vibrations to one vibration of the longer, while the loss of sensitiveness on that score only amountsto one-third. We can, therefore, by using such short beams, afford t o restore the requisite sensitivenessby lessening the distance between the points of gravity and suspension, and still retain to a great degreethe advantage of quick action.Another consideration of importance in this respect is the extreme light-ness of the beam as compared with the long one. The friction being much less, this would also causea greater freedom of action, and tend to accelerate tbe vibrations,The capabilities of this balance are such that it yields to the tenth part of a milligramme with thegreatest precision, and has a working range up to one thousand grammes.The appliance by which it is worked will be found extremely convenient. When not in use, all theknife edges are disengaged. By turning the handle, which is visible in the figure opposite, all the actingparts come into play one after the other. The whole range of motion of the handle is about one-half ofa turn.Beginning the operation, the pans are freed first; they are easily brought to rest by gentlybringing their stoppers in contact with them by carefully turning the handle back again once, or twice ifnecessary. When they are perfectly quiescent, the further turning of the handle engages the suspensionpieces by gently and simultaneously bringing their knife edges in contact with their supports ; the end ofthe handle motion suspeuds the beam, and the balance is ready for use. After use the handle is turnedback again, by which everything is set out of action. This arrangement, besides the great convenienceit affords, prevents all unnecessary wear of the acting parts.I n order to enable the final operation to be performed in the perfectly closed case.a parallel actionand sliding rod serves to lift the rider and place it in the required position with the greatest ease. Therider can be used the whole length of the beam.To ensure greater strength the whole is fixed to a stout glass plate which is supplied with two spiritlevels. Thepieces, when apart, fit in a box, and can be carried about without any fear of injury in the transport.The knife edges and their supports are made of agate, and most carefully finished.The form I have adonted for the smaller weights from 0.5 downwards will also be found very con-venient. They are made of wire, turned up into a flat spiral, the inner end projecting and forming a littleupright by which it can easily be taken hold Gf.The number of coils indicates the number of anits in eachdecimal, and the decimals themselves are distinguished by different thicknems of the wire.An inspection of this Bdance is respectfully solicited at my office, 55, Upper MaryleboneStreet, Portland Place, London, W.The Balance is so arranged that it can easily be taken to pieces and put together again.0. WOLTERS,(Rlany years with L. OERTLING,)dlanufactzlrer of Weights, Chemical, Assay and Bullion Balances.__THE ANALYST.INTERESTING FACSl MILE REPRINTS,In crown Svo., antique binding, or paper boards, 6s. ; antique morocco, 21s. ; large paper copies, inroxburghe binding, 21s. ; antique morocco, $2 10s.HE COMPLEAT ANGLER ; Or, The Contemplative Man's Recreation.By ISAACWALTON. This reprint of the first edition, published in 1653, is printed on paper similar to that ofThe quaint title page, the very clever drawings of fishes, and the antique head-pieces and the original.tail-pieces, are also faithfully copied by a photographic process, which exactly reproduces the original.ELLIOT STOCE, 62, PATERNOSTER Row, LONDON, E.C.In crown ~vo,, 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 i n Facsimile of the First Editlion 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 rea'.ise the rude form in which JohnBunyan put his immortal allegory before the readers of his own day.ELLIOT STOCK, 62, PATERNOSTER Row, 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 Ejaculations. By Mr. GEORGE HERBERT, T late Oratour of the Universitie of Cambridge, With an Introduction by the Rev. Alexander B. Gro8art,Editor of " George Herbert's Works in Prose and Verse," and of the Aldine Edition of '( Herbert's Poerns."'' 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 to 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 sawe 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 I."-The Times.ELLIOT STOCK, 62, PATERNOSTER Row, LONDON, E.C.IN THE PRESS.ARADISE LOST, by JOHN MILTON.A Reproduction in Facsimile of the FirstEdition.ELLIOT STOCK, 62, PATERNOSTER Row, LONDON, E.CTHE ANALYST.In Wrapper, 2s. 6d. On Roller and Varnished, 6s.\OOD CHAR?‘, giving the Names, Classification, Composition, Alimentary Value, Rates of Digestibility, E Adulterations, Tests, &c., of the Alimentary Substances in General Use. By R. LOCKE JOHNSON,L.R.C.P., L.R.C.S., &c.‘6 One of the most useful publications of the time.,’- Weekly Reuiew.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 ANGELL, F;B.M.S., PublicAnalyst, County of Hants.To be obtained of GILBERT, High Street, Southampton.LATTNER’S QUALI r ATIVE AND QUANTITATIVE ANALYSIS WITH THE BLOWPIPE. P Profusely illustrated, 515 pages, Svo., new, 1875. Published a t 21s. Offered for a short time at 6s. 6d.LETHEBY on Noxious Trades, 1s. post free. LETHEBY on the Right Use of Disinfectants, Is. post free.Milk in health and disease, by A. HUTCHINSON SMEE.London : HENRY EIMPTON, Medical Publisher and Bookseller, 82, High Holborn.Circulating Library, 21s. per annum. List of Works on Chemistry, &c., gratis.~-Ready, pp. iv. and 73, price 2s. post free.ITE ANALYSTS’ ANNUAL NOTE BOOK for 1875. Edited by SIDNEY W. T RICH. Contains the principal part of the Analytical matter of the pear in a partially condensed form,To be obtained through the Post only of S .W. RICH, 23, Lloyd Square, London, W.C.In the Press and will shortly be published a revised and fuller Edition.afUTTER; ITS ANALYSIS AND ADULTERATION. By OTTO HEHNER B and ARTHUR ANGELL, Public Analysts.F O E 8 SALE.NALYTICAL BALANCE, No. 3, by Ogrtling. Nearly new, in Glass Case. CostA ! .€8 10s. To be sold for $6 6s. A. DECK, Eing’s Parade, Cambridge.---2___-__ - __PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS,”Vol. 1, 1876.-( I 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 usefG1discussions on the general questions involved ; has produced through its members gomevaluable analytical papers ; and above all has led to 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 ofprosecutions in any respect typical, and many letters, articles, and stray notes, TheCouncil has acted wisely in publishing the volume.”-La;ncet.((This book should certainly be possessed by Public Analysts.”-Chemist and Druggist.6‘ This is rather more than it purports to be, since it contains a number of paragraphsand leading articles.”4 4 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.”-fion.THE ANALYST.Subscription-3s.6d. per annum, post free.All literary matter to be addressed t o G. W. WIGNER, 79, Great Tower Btreet, London, E.C.Business communications, Adarertisements, &c., to J. H. SCOTT, at the same address.Printed by ALFR :D BOOT, 7, Mark Lane, E.C., for the Proprietors ; andPublished by ELLIOT STOCK, 62, Paternoster ltow, E.C

ISSN:0003-2654    

DOI:10.1039/AN87601BP005

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

SOCIETY OF PUBLIC ANALYSTS. THE country meeting of the Society was held at Bath Street, Glasgow, on Tuesday, the 12th inst., Mr. Wanklyn in the chair. The minutes of the last General Meeting were read by Dr. Clark (who acted as local Secretary), and confirmed. Dr. Cameron referred t o the report of a case of adulteration of butter, which appeared in the last number of the I ‘ Analyst,” and which was said to be inaccurate, so far as it concerned Dr.Dittmar, and to an article which also appeared, headed ‘( Butter Analysis in Scotland.” After some discussion it was sugges- ted that Dr. Dittmar should be advised t o write to the t‘ Analyst ’’ and explain the matter. The following papers were then read, a discussion in most cases ensuing : On Enamelled Cooking Vessels, by R. R. Tatlock, F.R.S.E., F.C.S. Note on the Solution of difficult Soluble Substances, by A. H. Allen, F.C.S. On the Compositim of Gases Evolved in White Lead Stacks during the Corrosion of Metallic Lead, by (3. W. Wigner, F.C.S., and R. H. Harland, F.C.S. Messrs. Wallace, Tatlock, and Clark were thanked for kindly granting the use of their hall for the purposes of the meeting, and a special vote of thanks was accorded to Dr. Clark for his services as Secretary on the occasion,

ISSN:0003-2654    

DOI:10.1039/AN876010119b

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

120 THE ANALYST. ON ENAMELLED COOKING VESSELS. Read 6efore a Neetiny of the Society of Pu61ic Analysts at Glasgow, August 1 2 t 4 18’76, By R. R. TATLOCK, F.R.S.E., F.C.S. IT will be readily conceded that if it is requisite t o hare our food and drink pure and genuine, it is almost equally desirable that the vessels in which they are prepared for use, should be of such a character as t o ensure that they will not be subject to any contamination, or have imparted to them any quality which would render them injurious, or even objectionable. The Food and Drugs’ Act, 1815, does not make any provision for dealing with the sale of dishes, or vessels, which, on account of the nature of the materials from which thky are manufactured, must in many instances inevitably introduce poisonous or hurtful ingredients, into the food or drink, which may be prepared or contained in them; and it is questionable, whether officials appointed under the Act, would consider it any part of their duty to interfere with the sale of these.It is therefore all the more necessary that attention should be called to the question, in order that, if possible, moral influence as well as future legislation should be brought t o bear upon it.Brass vessels for boiling fruit, in making preserves ; and also ‘‘ preserved meat ” tins, the coating metal of which is partly composed of lead, have again and again been pointed out as examples of the articles referred to, but it is exclusively with enamelled cooking vessels that this communication has to do. The nature of “ Enamel,” or at least of the white, porcelainous kind most commonly met with on cast iron cooking vessels, admits of great variety as regards the ingredients it contains, and their proportions, upon both of which the properties and character of the enamel depend.Thus, we may have poisonous ingredients, such as Lead or Arsenic, present in comparatively large quantity, without the risk of having even a trace of either of these metals imparted t o any food cooked, provided sufficient silica has.,%been employed i n the composition t o make a glass not readily acted upon by common salt, vegetable acids or other ordinary dietetic substances.But if, on the other ihand, a deficiency of silica be used, the same proportions of lead and arsenic will give an enamel the use of which would be attended with great risk, on account of the easy action,upon it of many of the substances employed in the preparation of food.That enamels, in practice, differ largely in composition as well as in properties, will be seen from the following analyses and experiments, which refer to three samples of white opaque enamel taken from three cast iron cooking three different manufacturers. Silica ...........................Alumina ....................... Oxide of Iron ............... Lime ........................... Magnesia ........................ Oxide of Lead ............... Potash .......................... Soda ........................... Phosphoric Acid ............ Arsenious Acid ........... Carbonic A4d ...............Boracic Acid .................. Bases ........................... ... ... ... ... ... ... ... ... ... ... ... ... ... 1. Per Cent. 61.00 ... 8-00 ... 1.10 ... 3.02 ... -28 ... Absent ... 5.61 ... 20.67 ... Trace ... -02 ... -30 ... Absent ... pots as sold for use, made by 2. Per Cent. 42-40 2.88 2.04 -16 *10 26.89 7.99 14.6’7 Trace *42 Absent 3.45 100*00 38.68 ... ... ... ...... ... ... ... ... ... ... ... ... ... 3. Per Cent. 42.00 6.06 4.04 *78 ‘21 18.48 6.46 19.25 Traco 1-02 Absent 1.70 100.00 - - 55.28THE ANALYST. 121 The most superficial study of these Analyses will shew that Nos. 2 and 3, although differing considerably in composition, are of the same class, bdth being quite different from the No 1 in the following respects :- 1. The ratio of the total amount of bases simply added together, (without taking into account the difference in their combining proportions) to the silica is as 1 to 1.58 in No.1; 1 t o 9 9 in No. 2 ; and 1 to -76 in No. S , so that in the first-named sample the ratio of the silica to the bases is twice as great as in the other two. 2. Lead is absent in No. 1, while the other two contain it in very large proportion.3. No. 1 contains only 1-20 part of the amount of arsenic present in No. 2, and 1-50 of that contained in No. 3. At first sight it seems rather startling that a fatal dose of arsenic should be contained in one ounce of the enamel of a vessel intended for cooking purposes, but this fact alone would not 5e of so much consequence were it not for the basic character of the enamel, rendering it easily acted upon by ordinary dietetic substances, and even by water.It is impossible, however, to determine, from .the composition alone of any enamel, whether it will, in the ordinary circunistances in which the vessel is used, give out any of the poisonous ingredients which it may contain, and it, therefore, becomes necessary to ascertain this point by direct experiment.With this object the pot prepared with the No. 3 enamel was subjected to the following tests :- 1. A one per cent. solution of citric acid was boiled in the pot for a few minutes. The fluid was then cooled and tested for lead by sulphuretted hydrogan. A dense black precipitate was at once obtained, which settled immediately ; and on concentra- ting a further portion of the fluid, and testing for arsenic the presence of that metal was distinctly established.t 2. A quantity of water containing about 3 per cent. of common salt in solution was boiled in the same pot for a few minutes, and the solution cooled and tested with solution of sulphuretted hydrogen. A black precipitate of sulphide of lead was at once obtained. A further portion of the fluid was concentrated and tested for arsenic, but none could be found.3. A quantity of gooseberry jam was boiled for a short time in the same vessel, and the result tested for lead in the same way. The re-action was sufficiently distinct, but the presence of arsenic was not satisfactorily proved. A blank experiment shewed that thc jam did not contain a trace of lead originally.There was no difference in the appearance of these enamels, which could be of the slightest service in enabling any one to distinguish between them, 80 that nothing short of a chemical examination could determine whether they were objectionable or otherwise. I s may be worth noticing, however, that when the basic enamel is boiled with citric acid solution of 1 per cent.strength ; its surface loses its glassy appearance and becomes quite dull, while a perfect enamel is unaffected. It will be, of course, at once seen that the object of the manufacturer in the employment of arsenic, is t o obtain a milk white porcelainous enamel, and that by the use of lead, the materials can be fused at a much lower temperature, but it is evident from the analysis of the No.1 enamel, that both of these ingredients can be dispensed122 THE ANALYST. with, that sample being quite white, and yet containing only a comparatively minute quantity of arsenic, which on account of the siliceous character of the composition, is not acted upon by ordinary agents. The makers of the objectionable article are there- fore all the less entitled t o consideration.Thex must be well aware that they are introducing into cooking vessels, of even small dimensions, many fatal doses of arsenic, but they possibly are under the impression, through ignorance of the properties of the ingredients they are working with, that the arsenic is volatilised in the process of melting on the enamel. The action of salt and other substances upon these objectionable varieties of enamel is not the only means by which poisonous matter may be introduced into food.It may also take place by the cracking and subsequent breaking off of the enamel, and it is not difficult t,o see that this might readily take place in such a way that the substance would be in a highly comminuted state, and consequently would escape observation.It is undoubtedly very desirable t o have iron cooking vessels enamelled,. but if utensils thus prepared are not to be a sourue of injury t o health, one of two ways must be followed :-Either the poisonous ingredients must be entirely left out of the composi- tions, or these must be of such a character that they will not be acted upon by ordinary ingredients in the circumstances under which the vessels will be subjected to use. In a brief discussion which ensued: Dr. Clark, stated that several of the manu- facturers of enamelled pots were experimenting with the view of producing an enamel perfectly free from lead and arsenic, acd he had no doubt that if the attention of the public mas called t o the presence of poisonous Eubstances in the enamel of pots, manufacturers would immediately alter the composition of their enamels, and keep out the hurtful ingredients. Mr. 'I'atlock, stated, that he had purchased, within the last two days, two enamelled pots, one of which seemed free from objection and remained unaffected by a 1 per cent. solution of citric acid, while the other was acted upon to such an extent, that an enormous quantity of lead was dissolved out with ease.

ISSN:0003-2654    

DOI:10.1039/AN8760100120

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

122 THE ANALYST. CORRESPONDENCE. BUTTER ANALYSIS. To THE EDITOR OF THE “ANALYST.” SIR,-I hare no time to enter into a controversy on this subject, and even if I had, I think it is our duty not to squabble about small points of priority, but to work together in an amicable spirit, and finally to adopt whatever modification in the mode of estimating the fatty acids which map prove the most workable in our hands.The great point is the origination of the idea, and if Dr. Duprk will refer to the Food Journal for 1870, pages 586-7, he will there find that I was at that date engaged in studying the analysis of butter, and duly announced my process to be the estimation of amount of the fatty acids, which I stated would be found t o be the only reliable method. This much in self defence, and the rest I leave to time and experience in the hands of my confrires. Yours &c., JOHN MUTER.WE have received from Mr. Sidney W. Rich a letter criticising our criticism of his ( ( Analysts’ Annual Note Book.” We should have been glad t o h n e inserted Mr. Rich’s letter if space had allowed of it. At the same time we beg to assure Mr, Rich that we had no intention of treating him unfairly, and do not think we are open t o the charge of having done so. It cannot, however, be disputed that a great part of his matter is taken, without acknowledgment, from the 4 4 Proceedings of the Society of Public Analysts.” Whether from the bound volume or as they appeared weekly is not material.

ISSN:0003-2654    

DOI:10.1039/AN8760100122

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE ANALYST. 123 ON THE COMPOSITION OF THE GASES EVOLVED I N WHITE LEAD STACKS DURING THE COBROSION O F METALLIC LEAD. BY G. W. WIGNER, F.C.S., & R. H. HARLAND, F.C.S. Read before the Society of Public Analysts, at Glasgow, Augzcst 12th, 1876. THE ordinary process of manufacturing white lead by what is called the Dutch method is familiar to all chemists, but, as far as we are aware, no investigation has ever been made into the composition of the gases contained in the stacks during the process of corrosion.Such an investigation is, nevertheless, important, because it is these gases which ‘( corrode ” the metallic lead, and form the white lead, and the presence of an unusual proportion of any gas may alter the composition of the compound produced. In order to render the technical terms intelligible it may be necessary t o call attention t o the ordinary mode in which stacks are constructed.The stack is enclosed by four walls, generally approximating to a square, having one opening, called the door, from floor to roof. This opening is closed, as the stack is built, by boards fitting loosely together. The walls are sometimes lined as the stack is built by (( margins ” Some six t o twelve inch thick of tan, which are kept in place by loose fitting boards.In (6 building ” the stack a number of successive layers are added, which are some- what as follows : First, three feet of tan ; second, earthen pots filled with diluted crude acetic acid ; third, the lead to be corroded, cast into ‘( crates ” or ‘‘ plates,” and stacked loosely to a thickness of perhaps nine inches; 4th, a flooring of boards supported either on large pots or on suitable wooden supports.This flooring is generally double, so as to prevent small pieces of tan from falling through the crevices between the boards. These four layers constitute what is cdled a “ heat,” and the stack itself is composed of eight to twelve of these heats,” each subsequent heat differing only from the first in having a much thinner bed of tan, say 1 foot instead of 3 feet.The top heat is covered over with a layer of spent tan, t o retain the warmth. When the stacks are built, the tan (which usually contains about half its weight of water,) from its necessary turning over and exposure to the air, has a comparatively low temperature, which, although it varies greatly, may probably be averaged at 1000 E.When the stacks are finished and really a t work the temperature will rise much higher, sometimes even to 180” F. The proportion of actual acetic acid used is generally less than one per cent. of the metallic lead, and it is obvious that this cannot act to any sensible extent as a source of carbonic acid.This gas must, therefore, be produced almost, if not entirely, from the oxidation of the carbonaceous matter contained in the tan. The action of the acetic acid probably converts the lead into one of the sub-acetates, and the carbonic acid decom- poses this salt, forming a carbonate of lead. As it is clear that the tan has to produce the carbonic acid gas, we will consider the quantity of this gas necessary.I n a stack 15 feet square, and consisting of ten heats, about 35 tons of lead would be stacked, and at a fair estimate, one-half of this would be corroded, (say 176 tons.) The proportion of carbonic acid present in this white lead, will vary in extreme cases from lO& t o 16 per cent., but the average may be assumed t o be 1 2 i per cent. 22 tons = 49,280 lbs., 124 per cent.of which is 6,160 lbs. of carbonic acid required? assuming that no waste takes place. The bulk of this carbonic This will produce about 22 tons of white lead. This requires the combustion of 1,680 lbs. of darbon.124 THE ANALYST. acid will be about 53,000 cubic feet, at a temperature of 600 F. The same bulk of oxygen, will, therefore, be reqtlired for the production of the carbonic acid, but as atmospheric air contains less than 21 per cent.of oxygen, and as we cannot reckon that, under ordinary circumstances, more than one-third of this can be brought into combina- tion with carbon, at the temperature existing in the stacks, this 53,000 cubic feet will only represent 7 per cent. of the total atmospheric air requisite.The total quantity of air required will, therefore, be 757,000 cubic feet, even allowing for 7 per cent. of oxygen being utilized. This is, therefore, the minimum quantity needed, and the results of the analyses which we will give will show that this minimum is probably only a fraction of the quantity actually necessary. Such a stack as we have described will probably take twelve weeks to work.Twelve w eeks=120,960 minutes. The minimum quantity of air necessary is, therefore, only between 6 and 7 cubic feet per minute, or say the entire change of the air in the stack every six hours. Even allowing that these figures represent, as is probably the case, only about one- fourth of the actual quantity of air passing into the stack, the fact, that under these circumstances, the air in the stack would only be changed once in about 14 hours, and Would, therefore, have an upward movement at the rate of about 3 inches per minute, will probably be sufficient to account for the smallness of the air passages through the flooring boards, which have been found sufficient in practice to pass air from one heat to ilno ther.This explanation does not, however, seem to us sufficient to account for the imperfect mode in which air is at present admitted into the stack itself, namely, through the chinks in the boards forming the door.It appears obvious that all this air should enter through the bottom, i.e., the thick stratum of tan, and thence after being partially heated, and carbonated pass upwards, receiving fresh supplies of carbonic acid at each heat.In practice however, there is equal facility for the entrance of air at each heat, and this air is not compelled t o pass through any tan, (except the margins,) before it reaches the white lead, and its effect is consequently diminished. It seems clear that a due admission of atmospheric air below the bottom tan, combined with complete exclusion of in-currents at any higher point, would produce a more effectual and uniform corrosion than is at present obtained.Having thus considered the general points in the process employed at the present time, we will pass to the actual results obtained in the analysis of a large number of samples of gases taken while the stacks were at work. The mode in which these gases have been collected is as follows :-We have had an iron tube constructed for the purpose of driving or screwing through the door into the interior of the stack.This tube is about 6 feet long, made of 1 inch gas pipe turned smooth outside, at one end it is plugged by a pointed steel plug, drilled with a large number of holes about &-inch in diameter, t o admit the gas. At this end of the tube for a length of about 2 feet, a spiral of very thick iron wire, forming a screw of about 1 inch pitch is brazed on to the exterior of the tube; the other end is fitted with a double ended lever wrench, so as t o enable the tube to be turned round.The mode of using this tube is as follows :-A hole about 1-inch in diameter is bored in the door, the pobt of the tube is inserted, and the lever wrench turned round, the screw immediately seizes on the wood, and the t i b e is forced forward into the stack, when the screw losesTHE ANALYST.125 its hold on the wood, it retains enough hold on the tan to force its way in, and there is seldom any difficulty in getting the tube five feet into the stack. I f the point should come into contact with a (( pot,” the force is almost alwajs sufficient either to dislodge or break the latter.When the pipe is screwed in far enough, a registering thermometer is pushed in to the end, a small bent copper tube ;-in. diam. is then screwed on to the outer end of the iron tube, and the sample can then be taken. We prefer to collect the gas in one of the collecting tubes, a description of which by G.W. Wigner appears in the ( ( Proceedings of the Society of Public Analysts,” page 97, as by that means we avoid the trouble of sealing glass tubes, and also enable the gas to be more readily transferred to the laboratory tube for analysis. One of the India-rubber tubes on this collecting tube is slipped securely on to the bent copper tube already mentioned, and the other end is connected t o a small Tate’s air-pump fitted on a stand, and air equal to about twenty times the capacity of the entire tubes is exhausted.The screw clamps are then closed, the collecting tube containing the air detached, and the registering thermometer withdrawn to ascertain the temperature. The samples of air have all been analysed either by the McLeod apparatus, or by an improved form of it devised by Mr.Wigner. I n every sample, determinations of carbonic acid and oxygen have been made, and in many cases carbonic oxide and acetic acid have been tested for. As to the general characteristics of the samples, we may premise that we have analysed some hundreds of different specimens taken at all ages of and from many different positions in, the stacks, and we think we have therefore sufficient data on which t o base a sound opinion.All the samples were found t o be saturated with vapour ; this was of course to be expected from the presence of so much water in the tan, and diluted acetic acid. On drawing this moist air into the collecting tube condensation invariably took place, and we have tested this condensed water for acetic acid, but only one sample in the whole series has shown the least traces of it.We think that in this case the point of the iron tube had been forced into an acid pot, and a few drops of the liquor drawn over. It is therefore clear, that no sensible amount of acetic acid vapour can be discovered in the air of the stack. On another occasion we used an aspirator, and drew about two cubic feet of gas from a stack, in small bubbles through a wash bottle, but even in this way it was impossible t o say that acetic acid vapour was present.Nevertheless in some instances we have distinctly noticed the odour of acetic acid, as distinguished from the peculiar smell which the stacks always have. It was thought possible that some of the carbonaceous matter might oxidise into carbonic oxide, instead of carbonic acid, and a considerable number of samples were tested for this gas, but only in one case was any found.The sample in question was drawn from the second heat of a stack which had beeu thirteen weeks at work. The temperature had fallen very low, viz., to 106O, and the stack was consequently working very slowly. The proportion of carbonic oxide was -47 per cent.Other samples taken from the same place two or three days before, and two or three days later were tested, and did not show any carbonic oxide, and samples from other parts of the stack gave the same ncgatiye result. We cannot venture any opinion as to the cause of this exceptional sample, but can only say that we believe the analytical results to be correct.126 THE ANALYST L The percentage of carbonic acid gas present was found to vary to an excessive extent.The maximum and minimum found in our analyses, being respectively 27.27 per cent., and traces only.” These are beyond the ordinary variations, which usually range between 050 and 4.50 per cent. Up to the present time we have been unable to discover any rule governing these variations.They are evidently not dependent in any way on the age of the stack, for we have had samples of 5 weeks old giving *60 per cent, CO,, 1.16 per cent, COz, and 1.76 per cent., respectively, and of 9 weeks old giving a22 per cent., -67 per cent., and 2.92 per cent., and of 13 weeks old giving ‘‘ none,” ”75 per cent., and 1.33 per cent. respectively. Neither does the proportion appear to bear any definite relation to the temperature, for we have had a temperature of about 1500 associated with the entire absence of carbonic acid, and with the presence of 1-10 per cent, and 1.67 per cent.respectively, while with a low temperature of about 1100, we have had *07 per cent., -50 per cent., and 3.39 per cent. respectively. The only approach to a rule appears to be, that when a stack i x entirely worked off, Le., when the temperature has fallen t o say 105O, and the production of white lead has virtually ceased, it is rare to find more than about half a per cent. of carbonic acid present.It would certainly be an advantage t o the workpeople employed, if this portion could be removed prior to stripping. Some experiments made with this object, by opening a large aperture at the bottom of the door, and removing the cover of tan at the top, have been attended with partial success, and if proper arrangements were made it appears as if such an arrangement would prove advantageous to the product, as well as beneficial to the health of the people employed.The percentage of oxygen present in the samples is also very variable, but here, despite many discrepancies, there is some approach to a law governing the quantities found.This rule appears to be as follows : At the time of stacking, the air included in the stack is of course atmospheric, which, considering the character of the factory, may probably be assumed to contain 20.7 per cent. of oxygen. As the stack starts work this proportion diminishes, and after two weeks will probably average about 17 per cent ; after 5 or 6 weeks’ more work the proportion will be lower still, the average being prob- ably between 13 and 15 per cent, exceptional samples falling as low as 6+ per cent.This is unquestionably the period of greatest activity in the stack. After this tho pro- portion greatly, but irregularly, increases, and at 11 weeks will average about 17 per cent, I t still increases until the stack is practically worked off, when it will range from about 19.5 to 20.6 per cent. From this fact we find that it is possible to deduce one certain rule, namely, if a stack has been some few weeks at work, and the temperature has fallen to say 1100 or 115Q, and the analysis shows 19.5 t o 20-0 per cent.oxygen, with not more than ‘75 per cent.carbonic acid, all work in the stack is practically finished, and it is bettep to strip it at once rather than wait!, (even though the time is not up) for the comparatively trivial amount of corrosion which may be dill going on,THE ANALYST. 127 We will now pass from the general view of the question and give some specific A stack, which we will call No. 1, was sampled illustrations of the results obtained.when it had been nine weeks at work, and the results were :- 2nd Heat. 6th Heat. Carbonic Acid ... -00 per cent. -22 per cent, Oxygen ... 14.92 17.05 Temperature . , . 154)’ 15& It was again sampled two weeks later, the spouts through which the air escaped a t the top having been meanwhile partially closed.The results were :- 2nd Heat. 6th Heat. Carbonio Acid ... -50 per cent. -50 per cent, Oxygen ... 17.46 17.46 Temperature . , . 10th li9Q It will be observed that the temperature was 45” lower. The carbonic acid had increased, and the two samples, which previously differed greatly, were now identical in every respect. This last fact, we are inclined to think, indicates some slight displace- ment in the boards of the stack, so as to allow a more perfect circulation of the air from heat to heat.No. 6 heat was sampled one week later. The results mere :- 6th Heat. Carbonic acid ... ... ... *95 per cent. Oxygen ... ... ... .,. 13.25 Temperature ... ... ... 15% These figures are remarkably discordant from the previous results. They clearly Bhow that the stack had (‘ started work” again.Possibly this might be due to a sudden influx of fresh atmospheric air, due to the cause suggested above, but this is only a supposition. I n consequence of this anomalous result the stack was again sampled two days later at the same heat. The results were :- 6th Heat Carbonic acid ... ... 1. -17 per cent. Oxygen ... ... ... ... 17.92 ,, These results are fairly concordant with the results of last sample but one.After 9 days more, i.e. 13 weeks and 4 days altogether, the results were :- No. 2 Heat. No. 6 Heat. Carbonic acid ... ... -08 per cent. Traces per cent. Oxygen ... ... 19.45 16.13 Temperature , . . ... 9iQ 126: These last analyses clearly show that No. 2 heat had entirely stopped from useful The stack was allowed to work, but that No.6 was still probably doing good work. stand three or four days longer and then stripped. The produce of the stack was good in quality and quantity. A stack which we will call No. 2, was furnished with two spouts for carrying off When the stack was built these spouts were covered. The gas was sampled the gases. after four weeks’ work. The results were :- 2nd Heat.6th Heat. 7th Heat. Carbonic acid ... 097 per cent. *81 per cent. *60 per cent. Oxygen ... 17.56 17.44 ,, 14.53 Temperature , , , l l b ’ O * 184;; The covers were then removed from the spouts, and after twelve days more the results were :- 2nd Heat. 6th Heat. 7th Heat. Carbonic acid ... -67 per cent. -88 per cent. -56 per cent. Oxygen ... 17’86 ,, 16‘78 ,) 16.01 ,) The stack worked eight days longer, say seven weeks in all, the results then were :- 2nd Heat.7th Heat. Carbonic acid ... ... *96 per cent. - 7 1 per cent. Temperature ... ... 80°, 1660. Oxygen . . I ... 18.49 7) 13.60 3 )128 THE ANALYST. Some cause had evidently stcpped the work of the lower heats. The temperature 80* and the high oxygen 18.49 per cent. clearly show this, while the upper heats were working vigorously.Yet the proper “time ” of the stack was little more than half over. A sample of No, 2 heat, twelve days later, i.e. nearly nine weeks from start, confirmed this result. I t showed :- 2nd Heat. Carbonic acid ... ... ... ... Traces per cent. Oxygen ... ... ... ... ... 19.85 Temperature . . , ... ..I ..* 8;;. This analysis proved that very little action was taking place, and the second heat was again analysed fourteen days later on, or nearly eleven weeks from start.The results were :- 2nd Heat. Carbonic acid ... ... ... -39 per cent. Oxygen ... ... ... ... ... 17.89 Temperature ... ... ... ... 112);. These figures clearly prove that this heat was a t work again, and that the cause (which was probably due to an irregularity in the supply of air) which had produced the original stoppage had been removed.We were unable to sample this stack again, but when it was stripped the two bottom heats, which had given such anomalous results, gave poor corrosions and inferior white lead, while the upper heats were all extremely good. These results certainly point to the desirability of some ready mode of adjusting the inlet of atmospheric air instead of allowing it t o take its course through any chinks or crevices which may, and in fact are, produced by the irregular settlement of the stack.Having given these two examples of the consecutive samples taken from a given stack, we will now give in a tabular form, the averaged results of about 100 analyses, arranged in order of the age of the stacks at the time the samples were taken.These results are selected from the total number which we have obtained as being the most typical, or in other words as representing most nearly the maximum, minimum, and average results, obtained from stac,ks which were working in ordinary course, and not under any unusual conditions. AVERAGE RESULTS. Age in Days. 1 t o 10 11 y, 20 21 ,, 30 31 ,, 40 41 ,) 50 51 ,, 60 61 ,, 70 71 ,, 80 81 ,, 90 91 ,, 100 Carbonic Acid.*5 1 1 *64 3-40 -5 9 4 -29 1 ‘49 1-10 -65 ‘76 -46 Oxygen. 19.04 17-60 18*79 17.12 13-01 14.70 15.55 15.74 17.49 19.13 Maximuin and Mini- muin of Oxygen. 19.64 ... 18-73 20.22 ... 11.35 20.07 ... 16.36 20.47 ,. 12.64 20.61 ,.. 7.12 20.23 ... 6.57 19-77 ... 5.91 20.03 ... 6-63 20.24 ... 15.22 20.57 ...16.30 No. of Samples averaged. 3 11 7 4 12 9 13 12 15 15 One other point appears worthy of consideration in connection with this subject. The results which we have given tend to show the necessity of properly regulating the admission of air t o white lead stacks, and also confirms the old opinion that the temperature of the stack has a most important effect on the produce. The cooling effect of a considerable current of cold air, may under some circumstauces, be so detrimental a8THE ANALYST. 129 to more than counter-balance the good effected by the formation of carbonic acid, or in other words it may be desirable in some cases to heat the ingoing air.We are not at preseut prepared t o enter at all fully into the discussion of this question, but we will merely point out a fern of the facts.We have already shown that in our ideal stack, at least 1680 lbs. of carbon must be consumed t o produce the necessary carbonic acid. This carbon would in its combustion produce 24,450,000 units of heats, i.e., raise 24,450,000 lbs. of water, lo F. We have assumed that in round numbers 3,000,000 cubic feet of air, say 230,000 lb. must pass through the stack.The specific heat of air being '2374, and the increase of temperature necessary, being assumed t o average 60Q t 1 160@, we shall require 5,4'18,000 heat units to heat this air. The stack will contain, according to our estimate, 35 tons of lead, and perhaps 35 tons more of tan, pots and boards. At a fair estimate we cannot assume more than 500,000 units of heat for heating these.We have now about 18,500,000 units available for the evaporation of the water in the tan, and in the diluted acetic acid, and for replacing the losses occurring by the escape of heat from the spouts, &c. I f these latter losses are reduced as they ought to be to a minimum, we certainly ought to have surplus heat enough to enable 11s when it is required to let more air pass through the stack and so increase the oxidizing action, and the corrosion.I f air is admitted in this way, it is essential that i t be done with discretion, and in such a manner as to avoid unduly lowering the temperature of the stack. During these experiments we have upon several occasions analysed the air of the factory from which the samples were procured ; three samples taken from the top of the tan, covering the top heat have shown the following results :- No.1. No. 2. No. 3. Carbonic acid ... 0.00 per cent. -29 per cent. *78 per cent, Oxygen ... 19.83 ,, 19.59 ,, 18-25 ,, Three more samples taken from the confined passages closely adjoining the mouths of the stacks showed. xo. 1. No, 2. No. 3. Carbonic acid ... 0.00 per cent. 0.00 per cent.0.08 per cent. Oxygen 1 .. 20.46 ,, 20.35 ,, 20.18 ,, These last three are probably typical of the worst air which the workpeople would be compelled to inhale. I n conclusion we would point out that white lead makers may evidently gain much information from the periodical examination of the gas in the stacks, and that the careful collation, and examination of these results may enable improvements to be made in the process of white lead manufacture. We have intentionally avoided any reference to the analyses of the white lead produced in these stacks, as this paper is already, we fear, too long. In reply t o Mr. Allen : Mr. Harland, stated that the carbonic oxide found in one particular sample was determined by absorption with solution of cuprous chloride, after the oxygen had been taken up by means of pyrogallate of soda. Mr. Wanklyn, suggested, that the carbonic oxide had been formed by the action of the pyrogallate of soda, as some researches tended t o show that carbonic oxide was produced when oxygen was absorbed by this substance in the proportion in which it existed in atmospheric air. Mr. Harland, replied, that about 100 samples of the air from different stacks had been tested for carbonic oxide, each in exactly the same way, and under similar con- ditions, and that the slightest trace of absorption by the cuprous chloride (if amounting to only * 5 mm.), could be detected. I n every case, however, with the exception of the one instanced, the gas measured exactly the same, after cuprous chloride, as it did after treatment with pyrogallate of soda.

ISSN:0003-2654    

DOI:10.1039/AN8760100123

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

130 THE ANALYST. ON THE FRADULENT COLOURATION O F WINES. By A. GAUTIER. f Continzced.;) THE following Table (A) has been prepared, in order t o show the action of re-ageilts upon the substances employed for the fraudulent colouration of wines, both when the substances in question were in a pure state, and when mixed with pure wines, in such proportion, that of the total intensity of the colour of each mixture, about one-fifth was due to the foreign colouring substance. In all cases, before commencing the tests, the samples were shaken for some minutes, with one-tenth their volume of white-of-egg, albumin; (which had been previously diluted with one-and-a-half times its bulk of water), and then filtered, whereby the filtrate was rendered comparatively richer in the adulterating substances, shown in Table A.In order to make t1iesez:reactions practically useful, much care has been given t o the relative constancy and value of each, and as a result, a systematic method of research has been arranged and is shown in Table B. Even with every precaution in the process of examination, cases may arise in which some. uncertainty may exist. In such cases, further examination by other reactions must follow.The mention of one and the same substance may for that reason occur in various places in Table B. BUZZ. ~ O C . Chim., [ 2 ] XXV. 435-44 ; 403-498, and 530-538. PRELIMINARY PREPARATION O F THE SAMPLE. The wine to be examined is mixed with one-tenth its volume of white-of-egg, previously diluted with one-and-a-half times its bulk of water, well shaken, and after atanding for half-an-hour, filtered.If the wine is very poor in tannates, a few drops of a fresh acqueous solution of tannin should be added previous to tho agitation with albumin. The filtrate is treated with dilute sodium bicarbonate until its re-action is very feebly acid. All the re-actions of Table B, must be made on this liquid, except those for indigo, which are executed upon the albuminous precipitate.TABLE B. SYSTEMATIC PROCESS TO BE FOLLOWED FOR THE DETECTION O F THE NATURE OF FOREIGN COLOURING MATTERB ADDED TO WINES. A. Having placed aside the filtrate from the albuminous precipitate, the precipitate Two cases may present themselves : is washed until the washings are almost colourless. (u). The precipitate after washing, remains wine-coloured, lilac, or maroon, natural wine, or may be adoclterated with the greater part of the substames zcszcally employed.Pass on to C. (b). The precipitate is of a very deep wine colour, violet blue, or bluish, wines from the deegest colowed grapes; or wines coloured with ifidigo. Proceed to B, B. The precipitate is washed with water, then with alcohol of 25 per cent., a part is then removed and boiled with alcohol of 85 per cent.(u): A portion of the precipitate is removed from the filter, sus- pended in water, and carefully saturated with dilute potassium carbonate. The colour changes to brown or blackish brown natural wines, or may be adulterated with substances other than indigo. Pass to C. (b). The filtrate is blue.A portion of the precipitate suspended in water and treated with dilute potassiiim carbonate affords a deep blue liquid, which changes to yellow by an excess of the reagent. Various preparations of indigo. INDIGIO. The filtrate is rose, or whe-coloured.THE ANALYST. 131 C. Two C.C. of wine are treated with 6 to 8 C.C. of a 1-200th solution of sodiam carbonate, which must be added in slight excess (1 c.c.) after the change of colour. The liquid becomes lilac, or violat, sometimes the liquid becomes only winey, or dashed with violet.Brazil wood, cochineal, Portugal berries, ficchsine . . . . . . . , , ,. , ,. . .. . wines of certain sorts, fresh beetroot, logwood, both elders, whortleberries (myrtille), Portzcgal berries. (b). The liquid becomes bluish-green, sometimes with a faint lilac tint, wine, hllyhock, privet whortleberries, logwood, Portugal berries, fuchsine.Pass to MI. (c). The liquid becomes greenish-yellow without any blue or violet, beetroot, (old or fermented decoction), whortleberries, certain rare varieties of wine. Pass to L. The liquid C. a. is heated to boiling. (a). Pass to D. D. (a), The iiquid remains wine-violet, rose, or wine-lilac, or becomes a brighter lilac ; logwood, Brazil (b).The colour disappears, or changes to a yellow, or maroon, or reddish tint, wine, fuchsine, both 3. Treat 4 C.C. of the wine with 2 C.C. of each of a 10 per cent. solution of alum, and a 10 per cent. solution of crystalised sodium carbonate. (a). Clear yellowish-green lake (which may be bluish from mixtures of wines containing aramon), filtrate colourless, becoming very dightly yellow on warming ; its own volume of aluminium acetate a t 2 O B almost wholly decolourises it.On acidification with acetic acid, after treatment with its own volume of barium-hydrate (saturated solution), the wine becomes clear greenish-yellow aramon, pwre or mixed. (b). Greenish-blue lake, or dirty yellowish-green, according to the varieties present, sometimes very slightly winey. Filtrate bright-rose, gradually decolourised on warming, though retaining a tinge of lilac ; not decolourised by lime-water in the cold.COCHINEAL, ( 0 ) . Winey-violet lake, which darkens on exposure to the air. Filtrate bottle-green, or grey faintly red (if much logwood is present). The filtrate becomes green on warming.LOGWOOD. (a). Lilac, or maroon-lilac lake. Filtrate greyish with tint of maroon. On boiling this filtrate becomes fine old wine coloured. BRAZIL WOOD. Treat 4 C.C. of the wine with alum and sodium carbonate (as explained at E), (a). The filtrate is lilac or winey, Portugal-berries, fresh beehoot. (b). The filtrate is bottle-green, or reddish-green ; wine, fuchsine, black-elder, w1,ortleberriq beetroot.wood, cochineal, certain zrarizties of wine. Pass to E. elders ; whortleberries, Portugal berries, fresh beetroot. Pass to F. Filter. F. add to the mixture two or three drops of very dilute sodium carbonate, and filter. Pass to G. Pass to H. G. Treat 2 C.C. of the wine with subacetate of lead solution of density 1 5 O B. Shake. Filter.boiling. Lime water destroys the rose colour. PORTUGAL BERRIES. (a). The filtrate is rose which persists even when made slightly alkaline ; it slowly disappears on (b). The filtrate is yellowish, or brownish-red. FRESH BEETBOOT. H. (a). Deep blue. (a), Bluish-green. green, or faintly rose-tinted, wine, whortle6erries, beetroot, fuchsine. Pass to J. I. After the test H(a) treat a fresh quantity of 2 C.C.with 1.5 to 2 C.C. (according to its acidity and the depth of its colour) of an 8 per cent. solution of sodium bicarbonate charged with carbonic acid. (a). The liquid remains lilac for a moment, then changes to greenish-grey blue. Another specimen treated with sodium carbonate (according to C), and heated to boiling becomes dark greenish-grey. ELACX ELDER.(b). The liquid retains a lilac tint, or becomes grey with mixture of maroon, or dirty lilac. Another specimen treated with sodium carbomte (as at 0) tends to discdour on heating, the green being replaced by red. DWARF ELDER. The alum-lake obtained from F (6) was :- On treating the clarified wine with a few drops of aluminium acetate solution, it becomes a decided violet, or wine violet, BotJ& elders.Pass to I.132 THE ANALYST. ~~ J. Treat 5 C.C. of the clarified mine with a slight excess of ammonia, heat to boiling, and after cooling sbake with 10 C.C. of ether, decant and evaporate the ether, and treat the residue left on evaporation with acetic acid. on (a). The liquid becomes red. FUCHSTNE. (b). K. (a). (b). L. Treated with sodium bicarbonate according to the rules given at I.(a). The liquid is deep grey, slightly greenish, green, sometimes green with very slight lilac tint. The clarified wine, treated with an equal volnme of saturated baryta-water, filters after standing for The liquid does not become red ; wine, whortleberries, fresh bestroot. Pass to I(. Another specimen is treated according to C with sodium carbonate.The colour darkens or becomes red on heating, whortleberries, fresh beetroot, The greenish or bluish-green liquid, possibly having a winey tinge, has a tendency to discolour Pass to L. heating. Natwal wilze. fifteen minutes, dirty jellovr, or slightly green;.&. With an equal volume of aluminium acetate of 2 O B, it gives a lilac wine colored filtrate. With a few drops of aluminate of potash no change of colour.With sodium carbonate, employed as at Q, the liquid tends to lose its colour on heating. With barium peroxide, used according to Table A, column P, theliquid is faintly rose tinted, with or without an orange coloured deposit on the barium peroxide, NATURAL WINE. With the general characters above indicated, if with baryta-water it affords a madeira-coloured filtrate, chanlging to buff on acidulation with acetic acid ; if with borax it becomes deep-green with bluish caste; if with alum and sodium carbonate (as at E), a deep bottle-green with bluish tinge, precipitate falls, and if with aluminium acetate it remains rose-coloured with no change to violet-blue.TEINTURIER. (6). By treatment with acetate of alumina the filtrate is clear lilac.With a few drops of aluminate of potash the colour becomes that of the skin of an onion, and with a larger quantity of the re-agent the colour is green, tinged with maroon. With sodium carbonate (employed as at C) the fluid passes to yellowish or greyish-yellow, with tinge of red. With barium peroxide, flesh-coloured liquid with considerable orange coloured deposit in contact with the peroxide.BEETROOT, fermernted or not. The liquid is yellowish grey, with tinge of green or red. With baryta-water the filtrate is yellowish olive-green. With aluminum acetate the filtrate is bluish violet, or violet-lilac. With aluminate of potash, fresh rose, becoming yellowish.green, with an excess of re-agent. With sodium carbonate (as at C) the fluid becomes deep grey on heating.With barium peroxide the fluid is bleached, or remains but very slightly roseate, with a trace of orange deposit in contact with the peroxide. WHORTLEBERRIES. The liquid is reddish-yellow or brown-lilac. (c). M. The mixture of wine and alkaline carbonate f C) (6) is heated to boiling. (a). The mixture becomes lilac-violet, or violet. LOGWOOD. (a).The mixture tends to become decolourised, or changes to yellowish green, or dark green, or N. Treat the wine with alum, and sodium carbonate, as directed at f-F/ and filter. (a). The colour of the filtrate is lilac. Portugal-berries. (b). The filtrate changes to bottle-green, or reddish-green. Natural wifies, whortleberries, hollyhock, 0. Treat 2 C.C. of the clarified wine with 3 or 4 C.C.of a saturated solution of (G). The liquid remains wine-lilac, or with some violet tinge. Both elders, privet, Whortleberries. ( 6 ) . The fluid becomes bluish-grey-flax-blossom, greenish or bluish-grey with very faint trace of P. Treat a new portion of wine with sodium bi-carbonate, (as directed at I.) (a). The tint, at first lilac, changes afterwards to grey, slightly brownish, or to maroon.If a new portion be treated with sodium carbona.(,z, according to ((7) and then heated to boiling, it becomes clearer, and loses its green tint. maroon-green ; lzatural wines, whortleberries, both elders, privet, Portzcgal-berries, ficchsine. Pass to N. privet, both elders, fuchsine. Pass to 0. borax, according t o the intensity of the colour of the wine.Pass to P. lilac. Pwe wine, whortieberries, holyliocl%, fuchshe. Pass to R.TEE ANALYST. 133 The lake obtained according to (3) is deep blue-green. DWABF ELDER. (6). The specimen remains grey, tinged with green, bottle green, or yellowish. Sometimes (black elder) it acquires a lilac tint, Which almost immediately disappears, changing to a greenish-grey-blue whortleberries, hlnck elder, priuet.&. Treat a specimen of the wine with alum and carbonate of soda (as directed at E). (a). The lake remaining ou the filter is deep green-blue ; the filtrate is clear bottle-green. A sample treated with sodium carbonate (as at 0) darkens and becomes grey, slightly greenish, on heating to boiling. BLACK ELDER. A sample treated with sodium carbonate (as at C), and heated to boiling, changes t o dirty yellowish.PHIVET. A sample treated with sodium carbonate (according to 0) becomes deep grey on being heated to boiling. WHORTLBBERRIES. Pass to Q. Shake the mixture, and after a few moments throw it on a filter. (6). The lake is clear bluish or greenish. The filtrate is clear bottle-green. (c). The lake is ash-green faintly rose tinted. The filtrate is bottle-green, with tint of maroon.R. (a). The ether being decanted aid evaporated, the fluid residue becomes rose-coloured on treatment (b). The liquid left after the evaporation of the ether, does not become red on acidification with acetic 8. A sample is treated with its own bulk of a solution of aluminium acetate of (a). The colou: of mixture remains whey, natural wiraes, whortleherries, differentiate between them, (6).The colour of the mixture becomes violet-blue, hollyhock, whortleberries. Pass to T. T. Treat a specimen of the wine with ammonia and ether as directed at J. with acetic acid. FUCHSINE. acid, natural wines, hollyhock, whortleberries. Pass to S. 2 O B. as directed at ( I ; a), and ( I ; c ) . A specimen is treated with alum, and sodium carbonate (as at E), and after a few moments filtered .(u). The lake is clear green, dightly bluish, and rose tinted, filtrate is bottle green, with little maroon. With borax, (as at 0), particularly if the sample has been concentrated, the liquid is grey with trace of lilac- Two C.C. of the liquid treated with 3 C.C. of dilute ammonia, (I vol. of liq. ammonia with 10 vols. of water), and the mixture diluted with its own bulk of water, gives a liquid which is yellowish-grey, greenish or greenish-grey.The other characteristics (as at L). WBORTLEBERRIBS. ( b ) . The lake is green, slightly bluish, quite free from rose, filtrate clear bottle-green. With borax the liquid is greenish blue-grey. With ammonia (as above), dark bottle-green. With aluminium acetate, (as at S), bluish-violet colouration.HOLLYHOCK. Although somewhat difficult, this systematic method serves for the discovery of seyeral colouring matters mixed in one wine, if the indications of Tables A, and B, are carefully observed, and followed. I t is always desirable to determine the presence of Fuchsine, by the special re-actions given further on. By means of Table 3, the presence of one or several of the colouring matters may be detected, but before deciding, it is as well to verify by repeating, for the substances so found the re-actions of Table A, on the sample; and also the more special characteristics given further on, for the identification of those substances.SPECIAL RE-ACTIONS FOR THE DETECTION OF CERTAIN OF THE COLOURINGF XATTERS MIXED WITH WINES.Brad Wood.--Even a very strong clarification (two or three times more albumin than mentioned at the head of Table B,) does not wholly decolourise the adulterated134 THE ANALYST. wine. It becomes yellow-buff, which on exposure to the air, gradually changes to red. I f a wine that has been adulterated with Brazil wood is clarified, and then a skein of scoured silk, washed with dilute tartaric acid, be soaked in it for twenty-four hours, and then withdrawn, washed and dried a t 60' to TO", the silk will be found to be dyed lilac-maroon, or red.I n pure wine, the skein remains wine-coloured or lilac. I f the dyed silk be now dipped into dilute ammonia, and heated to 1000 for a moment, it becomes lilac-red, if Brazil wood was present; but deep grey with scarcely a tinge of its original colour if the wine were pure.I f the ammonia be replaced by lime-water, the skein changes to ash-grey if Brazil wood were present ; but t o a dark, dirty-yellowish-red, if the wine were pure. Finally, if the skein be dipped into aluminium acetate, and then heated to looo, it retains its wine-red lilac colour. This re-action differentiates Brazil wood from Logwood.Logwood.-If the colour due to Logwood is in excess in the wine, ammonia gives it a shade of violet; if the proportion of Logwood is small, the re-actions B, A, fl, of Table A, which are very delicate, should be tried. Treated with a skein of silk, prepared in the manner described for Brazil wood, it becomes dyed lilac-red, or maroon, which dilute ammonia changes to violet- blue tinged with grey, and which by acetate of aluminium becomes bluish-violet.Cochineal.-The lilac, or roseate tints due to the re-actions A, B, B, K, of Table A, are very sensitive, the last being very characteristic ; the only substance likely to be confounded with it, being the phytolacca, (Portugal berries), which is differentiated by the re-action B.of the same Table. A skein of scoured silk, mordanted with aluminium acetate, soaked in the clarified wine for 20 hours is dyed of a wine violet colour, analogous to that of pure wine, on being dried at loo0. The colour does not change, even at looo, by cupric acetate (exclusion of fuchsine), but if the skein be dipped into a dilute solution of zinc chloride, heated to looo, and then wetted with sodium carbonate, washed with water and dried, the colour becomes fine purple, whereas1mith pure wine, the tint would remain sombre grey-lilac.Cochineal may be discovered by the spectroscope if present in large quantity, but if it amounts to only about 12 per cent. of the total colouration, it cannot be so detected. It rapidly separates from wines, being precipitated in the lees.Fuchsine.-This should be sought for in all wines found to be adulterated with other substances. The re-action J. of Table B: is very sensitive. Great care must be taken to avoid loss of rosaniline from imperfect decomposition of its saltsk solution, moreover, arsenic should always be sought for where the wine is found to contain any analine. Fuchsine rapidly separates from the wines to which it has been added A skein of silk becomes dyed rose by soaking in a wine adulterated with fuchsine and its colour passes to yellow on treatment with hydrochloric acid, but to bright red, if the wine was pure, The dyed skein treated with dilute cupric acetate, and dried at 1009 becomes fine deep rose-violet if fuchsine is present, and of a lilac tinged with ash-grey if the wine is pure.The rose or lilac colourations of the re-actions A, G, and especially C of Table A :.re very sensitive. This re-action is very sensitive. PhytoZacca.-(Portugal berries).THE ANALYST. 135 Hollyhock.-(Althea rosea), much used. This substance imparts a peculiar flavour which in a few months becomes actually disagreeable, while the colouring matter itself rapidly precipitates.The lilac tint of re-action C of Table A, if the beetroot is fresh, and the yellowish colours due to alkalies, (re-actions D. E. and F. of Table A.) are very sensitive even with old decoctions. Black Elder, Dwarf Elder.-The dwarf elder imparts a faintly turpentinous odour to the wines. The berries of both varieties are particularly used to communicate a special colour and flavour t o port wine.The teinte de Fismes, which is largely used at Fismes, Paris, and elsewhere, is made by digesting 250 t o 500 parts of elder berries, and 30 to 60 parts of alum, with 800 t o 600 parts of water, and then submitting the mixture t o pressure. M. Maumeni reports having discovered as much as 4 to 7 grammes of alum per litre in wines adulterated with this substance. Sometimes (though rarely) the alum is replaced by tartaric acid.Wines adulterated with elder, yield a violet-blue lake (reaction H, table A). By comparison with pure wine the difference is very marked. A piece of flannel, or skein of silk, mordanted. with aluminium acetate, heated for some time in the suspected wine, then washed, and immersed in water made faintly alkaline with ammonia, becomes green if the wine is pure, but dark brown if black elder is present.Privet.-This is very seldom used. The general reactions, particularly N and P of Table A, must be relied on. Myrtille, (Whortleberries) .--Very seldom used, and only for the commonest wines. The principal characteristics are given in 1; (c), Table B. I n wines suspected to be adulterated with this substance, citric acid should be sought for, its presence being one of the best indications of the adulteration.The re-actions A (6) and B (6) of Table B, are so sensitive that they are alone sufficient to characterise indigo, Wool or silk mordanted with aluminium acetate, heated with 20-40 C.C. of the suspected wine nearly t o dryness, washed and then dipped into very dilute ammonia become dirty green if the wine be pure, but blne if indigo be present. Indigo being often used to mask the too bright colours of cochineal and fuchsine, they should always be sought for after the removal of the indigo by clarification with albumin. Indigo very rapidly separates from wines, and it may frequently be found in the lees, even when the wine iteelf gives no indication of its presence. Substances other than those mentioned are occasionally employed for the adulteration of wines ; among them are archil residues, sulpho-purpuric, and sulpho-alizaric acids, and their salts, but these have only recently been introduced, and are not yet seriously employed. Except in such cases as indigo and cochineal, it is only upon a series of concordant re-actions that the presence of an artificial colouring matter should be affirmed. Beetroot.-This is generally employed only to mask other adulterants. Probably the same reaction occurs with dwarf elder. Indigo. C. IT. P.

ISSN:0003-2654    

DOI:10.1039/AN8760100130

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

136 THE -4NALYST. ~~ PROSECUTIONS UNDER THE SALE OF FOOD AND DRUGS’ ACT. Mr. G. R. Toogood, grocer, was charged before the Stockton Borough Bench, with selling adulterated oatmeal. The case was before the Bench on a previous occasion, when it was stated that two samples of the oatmeal had been analysed by Messra. Stead and Pattinson, of Newcastle, and found to contain 1+ and 1 per cent. of barley only respectively.Mr. Edger, of Newcastle, had analysed it, and showed that there was 25 per cent. of barley in it. The samples had been sent to Somerset House for analysis, and it was certified that they contained 15 per cent. of barley, and 4 per cent. respectively. The Bench fined defendant 21., including costs.-Messrs. W. Webster and F. Heaton were also charged with largely adulterating oatmeal, and were fined 31., including costs.-Mr.A. Holmes was also charged with the same offence, and was fined IZ., including costs.-The Co-operative Society were also charged with adulterating oatmeal with 25 per cent. of barley, and fined 1Z. including costs.-Messrs. W. Jackson and Geo. Brown were also charged with selling oatmeal adulterated with 20 per cent.of barley, and were fined IZ., including costs. Mr. John Hopley, provision merchant, of 340, Deansgate, appeared at the City Police-Court, Manchestar, charged with having sold a quantity of lard which was not of the nature, substance, and quality of the article demanded by the purchaser. Mr. Talbot said the lard was bought by Mr. Rook from the defendant, and on being analysed it was found to be adulterated with 16 per cent.of water, There had been several cases under the 6th section of the Act, principally for the adulteration of milk. Convictions had been obtained, but a point had been raised, which caused the justices to to defer the present case until the return of the stipendiary magistrate. By the 25th section of the Act, it was enacted that if the defendant has a written warranty he shall be discharged from the prosecution.Mr. Cobbett would say that he had a written invoice in which the article was described as lard, and that such description being in writing would amount to a warranty under the statute. Careful reading of the Act, and subsequent reflection, led him (3Tr. Talbot) to the conclusion that the Act intended there should be something more than a mere invoice ; it required that there should be a guarantee in writing, distinctly setting forth the quality and description of the article in order to avoid conviction under the 25th section.The warranty of an invoice aas of the very slightest character, and it ought to be more specific in order to come within the meaning of the section.If the magistrate ruled in favour of the defendant, the mere production of an invoice would render the Act a dead letter, which was a very undesirable state of things, as most business was carried on by means c.f invoices, and in every case the defendant could procure one very easily. Tn order to satisfy the Bench something more than a mere piece of paper with “lard” written upon it must be produced by the defendant, Mr.Estcourt, the city analyst, stated that on being analysed, the lard was found to be adulterated with 15 per cent. of water. Mr, Cobbett, in reply, said the defendant obtained his lard, butter, &c., from a Mr. Wm. Walker, who was a cheese factor and provision merchant in Liverpool. On July 3rd, the defendant bought from Mr. Walker, in Liverpool, amongst other things, four tins of lard for $2 15s.He received with them an invoice, on which was stated, ‘‘ Bought from Wm. Walker, four tins of lard, &c.” He asked Mr. Walker if the lard was pure, and he replied that it was. The lard was conveyed to Hopley’s shop in Manchester, and was never touched after its arrival, until the purchase of a portion by Superintendent Rook.Upon those facts he (Mr. Cobbett) proposed to ask the Bench to dismiss the summons, and he did so upon these grounds : the section of the Act said L L the article demanded by the purchaser.” Mr. Rook asked for lard, and the defendant gave him what was to his belief lard, but which turned out to be lard and water. That, however, showed no guilty knowledge on the part of the defendant, but was rather a ground for proceedings against the vendor, Mr.Walker. The only material question was as to whether the invoice was such a warranty as was mentioned in the section. All the good authorities showed that no particular form of words was necessary for a written warranty ; and though it might be said that there was no proof that the invoice had ever been Been by Mr.Walker, it had been decided that his name written or stamped on the biil-head was sufficient proof of his knowledge of its existence. The defendant was called, and bore out by his evidence Mr. Cobbett’s statement. The case was adjourned. --Mr. Joseph Nuttall, provision dealer, of 213, Deansgate, was also summoned for having sold to Mr. Rook, lard adulterated with water to the extent of 15 per cent.The defendant said he bought the lard from a wholesale dealer, but he could not at the moment lay his hand on the invoice This case was also postponed for a fortnight.-Mr. Samuel Gouldburn, 141, Ridgway Street, was charged with having sold to Mr. Rook, superintendent of nuisances, milk which was “ not of the nature, substance, and quality of the article demanded by him,” was fined 51.and costs. The milk was adulterated with water to the extent of 9 per cent.-Mr. Edward Hayes, was fined 40s. and costs, for having on August 15th, sold a certain article of food, to wit, mustard, which was adulterated by the addition of 15 per cent. of starchy matter.- Mr. Charles Bostock and Mr. David Sewelson, were each fined 40s. and costs, for selling mustard which was not of the nature, substance, and quality of the article demanded. I n the case of Mr. Bostock, the mustard was adulterated by the addition of starchy matter to the extent of 15 per cent., and in the case of Mr. Sewelson, the adulteration exceeded 25 per cent. There was no water naturally present i n lard. If the case were adjourned, he would produce it.

ISSN:0003-2654    

DOI:10.1039/AN8760100136

出版商:RSC    

年代:1876

数据来源: RSC