摘要:

THE ANALYST. FEBRUARY, 1588. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE Annual Meeting of the Society was held at Burlington House on Wednesday, the 11th January, the President, Mr. Allen, in the chair. On the minutes of the previous meeting being read, Mr. Johnstone called attention to a statement made ah the last meeting to the effect that he was unwell, which, he said, was made without authority, and was due to a misunderstanding, as he had not been unwell but only unable to attend the last meeting. Mr. JOHNSTONE then presented the acrounts for the past year, audited by himself and Nr. Fdx, showing a balance at the banker’s of &151 9s. Id. Mr. ADAMS thereupon moved, and Mr. Dyer seconded, that &lo0 be invested in gome Government funds or British Railway debentures ; which was carried unani- mously.On Mr. ADAYS rising to propose the resolution of which he gave notice at the December meeting, aR reported in THE ANALYSr for January, respecting the appoint- ment of Mr. F. Low, as Solicitor of the Society, Mr. JOHNSTONE rose to a point of order, as the motion had been ordered to be on the agenda for that evening, and it was not there. The PRESIDENT said it was certainly an omission, but, unless Mr. Johnstone could show a rule to the contrary, he should hold that Mr. Adams was entitled to proceed with his motion, of which due notice had been given and published in their journal. Mr. JOHNSTONE said he merely wished to call attention to the irregularity. Mr. ADAMS then moved, ‘‘ That Mr. F. Low, of 17, King St., Cheapside, be appointed Solicitor to the Society, and that whenever legal business i s likely to come before the Council he be requested to attend,’’ The minutes were then confirmed.22 THE ANALYST.After considerable discussion Mr. ALLEN explained the reasons for appointing a solicitor ; he said they were continually suffering in various parts of the country from having cases defended by actual barristers, or by solicitors who had great practice in such matters, while the only person to represent the interest of the prosecution was a sanitary inspector, who had no weight with the magistrates, and, in cases where they had a dispute, was incapable of showing that previous cases had been decided in a similar way. It was thought to be desirable that they should have some man who would make a point of mastering the cases which had arisen under the Sale of Food Act, and who could, if necessary, be called on to undertake the prosecution of any cases which occurred, and most of them had known of cases where such assistance would have been highly desirable.It was proposed to give Mr. Low some sort of official position, and, as the legal adviser of’ the Society, he would be invited to attend their Council meetings, There was no responsibility on the part of the Society involved in the matter. The Society would have nothing to do with any payment to him, as the local boards who might employ him woiild have to arrange that. Mr. ADAMS said that Mr. Low was the son of a connty magistrate, and the brother of a barrister, and practised himself in the heart of the city of London.He considered him a very competent man, and one who was particularly eligible for the appointment. Turning from that, he would point out how essential such an appointment sometimes was, There was no one they could employ, although the county authorities wished to do so, and gave him c m t e bZanclt,e ; but there was no one but a mere inspector. He (Mr. Adams) went to a solicitor, who turned out to be a regular dummy, and those who had been placed in such a position would know what a great advantage it would be to be able to put their finger a t a moment’s notice on a man who had made a study of the matter, and who had had facilities afforded him for seeing the various processes carried out. The necessity for it had occurred to him in his own practice.The question was still further discussed. Mr. JOHNSTONE stating that no one outside the Council knew anything about the matter except those who were present at the last meeting. Mr. DYER said he was not at all sure that the Council could not have decided the question themselves. It had been discussed a t considerable length at one Council meeting and referred to a Sub-Committee ; that Committee had reported to the next Council meeting, and, more as a matter of form than anything else, it now came before the general body of the members. Ultimately, at the suggestion of Mr. KINCZETT, Mr. Adams altered the terms of his motion, so that it should read, ‘‘ That Mr. F. Low be appointed solicitor to the Society in an honormy capacity,” and on this being put to the meeting it was carried unani- mously.The PRESIDENT then delivered his annual address as follows :- PRESIDEST’S ADDRESS. IN accordance with the custom of my predecessors in this chair, at the conclusion of my p a r of ofice I present to you a short rEsun2i of the past and present position of the Society,THE ANALYST. 23 I n the first place, I think we may congratulate ourselves on the position of the Society, both numerically and financially. During the year we have elected sixteen new members and eight new associates, while, as a set-off against this increase, there are ten members and five associates who have either resigned or been removed ,from the list of the Society for non-payment of their subscriptions. It is pleasant to have to record that during the past year no death has occurred among the subscribers to the Society.The numerical progress made by the Society is shown by the following figures :- 1885. 1886. 1887. Honorary Members 10 . . 10 . . 10 Ordinary Members 149 . . 152 . . 158 Associates . . .. 22 . . 25 .. 28 Financially, the Society also shows an improvement, the balance in hand being, I am informed, about $150, as against &lo0 on the occasion of the annual meeting last year. Not only has the Society made satisfactory progress numerically and financially, but the number of interesting and important papers have been such as fully to maintain the standard of previous years. It is indeed encouraging, and a striking evidence of the vitality of the Society, that the number of papers contributed during the year has been as high as thirty, many of which, as will be seen by the following list, mere of a very useful and important character.Jan. 12. ‘ I Arsenical Glauber’s Salt” . . . . . . . . . . , . Charles Cameron ,, ‘ I Estimation of Methyl-Alcohol ” . . . . .. .. . . Otto Hehner .... Poivrette” . . . . . . . . * . . . .. . . J. Campbell Brown Feb. 9. “ Composition of Milk and Milk Products ” . . . . . . P. Vieth ,, ‘‘ Determination of Glycerin in Fats ” . . . . . . . . Otto Hehner ,, ( I Pavy Sugar Test ” . . .. * I . . . . . . . , S. Stokes ,, “Additional Note on Poivrette ” . . . . . . . . . . J. Campbell Brown March 9. ‘ I Further Experiments on Volatility of Glycerin ” . . . . Otto Hehner ,, “ Experiences of Curious Impurities, Admixtures, and Sub- stitutions ” .* . . . . . . * . . . . . A. H. Allen April 13. “Admixture of Starch with Yeast ” . . .. * . . . W. F. H. Stock ,, “ Testing Skim Milk by the Lactometer”. . . . . . . . Harold Faber ,, “ Another New Pepper Adulterant ” . . . . . . . , J. Campbell Brown ,, “ On Flitwick Water ” .. I . .. .. . . . . W. Johnstone May 11. “ An Improved Method of Dekcting Quassia and Certain Other Hop-Substitutes in Beer . . .. . . .. . . A. H.Allen Substitutes . , . , .. .. .. . . . . W. Chattaway ,, “Note on the Composition of Some Preparations Sold as Hop- A. H. Allen and ,, ‘‘ On the Beer and Butterine Bills ” . . * . . . . . Otto Hehner June 8. Notes on the Logwood Test for Alum in Eread ” . , . . W.C.Young ,, “ Quantitative Determination of Pepper Mixtures ” .. . . A. W. Stokes ,, L‘Pepper” . . .. .. .. .. . . . . . . T. Stevenson ,, ‘‘ On the American Methods of Manufacturing Oleomargarine, and the Laws Recently Framed on the Sirbject in the United States” . . . . .. .. . . . . . . J. Muter July 32. ‘‘ Examination of Wort ” . . . . .. . . * ‘ * * 1 E. W. T. Jones ,, I‘ Estimation of Starch ” . . . . .. .. .. ,.24 THE ANALYST. Nov. 9. 9 ) 7 9 9 ) 9 , 97 Dec. 33. 1 ) “ Allowance for Decomposed Milk ” .. .. .. . . “ Preservation of Milk Samples ” . . .. . . .. .. I‘ Substitution of Asbestos Cloth for Blotting-Paper ” . . ‘‘ Does Neutral or Sub-Acetate of Lead Precipitate Hop Bitters ? ” “ Filtration ” . . .. * . .. . . .. .. .. “ Alumina as a Natural Constituent of Wheat -Flour ” . , . .“ Estimation of Peroxide of Hydrogen ” . . . . .. .. ‘( Relation Between Specific Gravity, Fat, and Solids not pt, on the Basis of the Society’s Process for Milk Analysis . . . . A. W. Stokes Otto Hehner W. Johnstone W. Johnstone Hehner 65 Richmond W. C. Young C. Kingzett Hehner & Richmond In addition to the formal papers in the foregoing list, highly interesting and important discussions have taken place in connection with the proposed legislation respecting Beer and Butter-Substitutes, and it is satisfactory to know that the Society was able to make its influence felt, and that its interests were directly represented before the Select Committee on Butter-Substitutes, which sat during last Parliamentary session. As a consequence, we may congratulate ourselves that the Margarine Act., which became law on the first of this month, is a far more satisfactory working measure than appeared probable from either of the Bills brought in.The clause introduced on the suggestion of Dr. James Bell, enabling an inspector to take any un-labelled sample of what is apparently butter without previously going through the form of purchase, appears likely to be of great value in practice, and it is to be hoped the same principle will be extended to certain other articles whenever a general amending Act is passed. That the passing of such an amending Act is highly desirable will be admitted on all sides, and, in my opinion, the time is ripe for us to take all the steps in our power to urge the Government to undertake the requisite legislation. Circumstances have greatly changed since the Public Analysts were first appointed under the Adulteration Act of 1872; and even when the Parliamentary Committee sat in 1874 the Society of Public Analysts had no existence, and there were no means of taking combined action or making their wants felt.Furthermore, in 1872 there were no generally recognised methods of examining food, and many of the published processes were wholly untrustworthy. Even where properly qualified chemists were appointed as analysts, they were severely handicapped by the general want of a medium for exchanging ideas, and unfortunately in too many cases sanitary authorities insisted that the medical officers of health who were appointed contemporaneously, many of whom were perfectly innocent of a knowledge of chemical analysis, should also undertake the duties of food analysts. Now, however, by a process of natural selection and sur- vival of the fittest, the Public Analysts of the country are a body of highly trained and eminently competent men.By individual industry and combined eflorts exercised through the medium of this Society, unassisted by Government grants or patronage, and without either much aid or sympathy in quarters where they might fairly have expected it, they have mastered, one by one, some of the most difficult problems of food analysis, and it has now become an everyday practice to analyse, with sufficient practical accuracy, articles of food which seemed at first to defy all efforts. I n 1872, and for some years afterwards, the mere detection, to say nothing of the determination, of foreign fatty matters in butter with sufficient certainty to justify proceedings against the vendor, appeared an almost hopeless problem; but, thanks to the ingenuity of Hehner andTHE ANALYST.25 Angel], supplemented by the industry of Dupr6, Muter, Jones, James Bell, and other chemists in England, of Koettstorfer and Reichert in Germany, and Caldwell, Waller, Moore, and other chemists in America, i t is now possible to detect and estimate very moderate proportions of adulterants in butter. Our methods of examining tea, coffee, mustard, and other groceries have similarly improved, while the beneficial effect of the enforcement of the Act will be seen in the fact that adulteration of these articles is far less common than was formerly the case.The adulteration of flour and bread by alum is another practice which may still linger in certain districts, but bids fair soon to become almost obsolete. Whatever may have been the practice formerly, the experience of public analysts of late years shows that the vile adulterations said to be practised in the case of spirits and other alcoholic liquors are now simply historical. I n the case of beer, the Public Analyst can do little so long as there is no legal definition of its nature ; but we have serious reason to complain that a clause should have been smuggled into the Customs and Inland Revenue Act of 1885, which was essentially a prohibition against the watering of beer by brewers after fermentation, or by dealers and retailers of beer. This clause, which was practically an Amending Act, so far as related to the adultera- tion of beer, was passed without regard to the existence of Public Analysts, and provided for the detection of adulteration by the Inland Revenue Officers. It is only right the public should know that public analysts were not concerned in and had no power to take such proceedings as those which have been common in London during the past year, according to which it is contended by the Inland Revenue that it is illegal and a fraud on the Revenue to mix together two different kinds of beer, although each of these has already paid duty according to its character.But the gravest disadvantage under which public analysts linger, and the direction in which an alteration of their present position is most urgent, consists in the present regulations respecting the reference of milk and other perishable articles to the chemists at Somerset House.This matter has been so recently and fully discussed that it is un- necessary for me to refer to it at length, but I cordially endorse the opinion expressed at a recent meeting of the Society, that the time for mere talk is at an end, and that public analysts should take formal action by a memorial addressed to, or deputation waiting upon, the proper authorities. So long as we content ourselves with simply grumbling, so long the present condition of affairs is likely to continue; but I believe there is now such an overwhelming mass of evidence of the failure of justice under the present system that the authorities would feel bound to take action of some sort if the matter were brought formally before them.Dr. VmrH proposed a vote of thanks to the President for his services during the past year. He had made a great sacrifice of time and had taken a great deal of trouble over their affairs, having attended every single general and council meeting during the year. The vote having been carried unanimously, the PRESIDENT returned thanks and proposed a vote of thanks to the officers of the Society for their services during the past year. The President also proposed a vote of thanks to the Council of the Chemical Society for the use of their rooms. On the ballot papers being opened it was announced that the following were elected as the Officers and Council of the Society for 1888 :-26 THE ANALYST.PresicZent.-A. H. Allen, F.C.S., F.I.C. Vice-Presidents (who have filled the office of President).-A. Duprb, Ph.D., F.R.S., F.C.S., F.I.C. ; C. Heisch, F.C.S., F.I.C.; Alfred Hill, M.D.. F.C.S., F.I.C.; J. Muter, Ph.D., M.A., F.R.S.E., F.C.S., F.I.C. (Who have not filled the office of President).- S. Harvey, F.C.S. ; P. Vieth, Ph. D., F.C.S.; C. R. Alder Wright, D.Sc.,F.R.S., F.C.S., F.I.C. Z’reasurer.-C. W. Heaton, F.C. S., F.I.C. lion. Secretaries.-Bernard Dyer, B.Sc., F.C.S., F.I.C. ; 0 tto Hehner, F.C.S., F.I.C. Other Members of Council.-J. Baynes, F.C.S., F.I.C. ; J. A. R. Newlands, F.C.S., F.I.C.; E. Seaton, M.D., F.R.C.P.; W. J. Sykes, M.D.; J. A. Voelcker, Ph.D., B.Sc., F.C.S. The names of those Members of Council whose term of office has not yet expired, and who consequently do not retire this year, are M. A. Adams, F.R.C.S., F.I.C. ; W. Fox, F.C.S. ; C. N. Hake, F.I.C.; C. T. Kingzett, F.C.S., F.I.C. ; W. Boverton Redwood, F.C.S., F.I.C.; W. F. I(. Stock, F.C.S., F.I.C.; R. R. Tatlock, F.R.S.E., F.C.S., F.I.C. The following gentlemen were also elected :- As Members : Laurence Briant, analyst ; John Heron, F.C.S., F.I.C., analyst ; As Associate : E. Michael, assistant to Mr. Stokes. The PRESIDENT read a paper on The Annual Dinner was afterwards held at the Criterion Restaurant, Piccadilly, when a very pleasant and convivial evening was spent, notwithstanding the dense fog which prevailed outside. The next meeting of the Society will be held at Burlington House on Wednesday, the 8th inst. W. E. Matthews, Melbourne, public analyst. Laboratory Notes.”

ISSN:0003-2654    

DOI:10.1039/AN888130021b

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

26 THE ANALYST. ON THE RELATION OF SPECIFIC GRAVITY, FAT AND SOLIDS-NOT-FAT I N MILK, UPON THE BASIS OF THE SOCIETY OF PUBLIC ANALYSTS’ METHOD. BY OTTO HEHNER AND H. DROOP RICHMOND. (Read 6efore the Xociety o n December 14th, 1887.) IT will be within the memory of some members of the Society that a few years ago one OF us worked out a formula which expressed the relation between specific gravity, fat, and solids-not-fat in milk (ANALYST, vol. vii., p. 129), upon the basis of the Wanklyn process, which was then still in general use among analysts. The formula did not lay any claim to originality, for both Behrend and Morgen, and Clausnitzer and Mayer bad previously given formulz intended to express that relation. It, however, drew the attention of public analysts to the fact that there was such a relation, which formerly was by no means generally recognised.The Wanklyn process of direct extraction of fat from the milk solids being now,26 THE ANALYST. ON THE RELATION OF SPECIFIC GRAVITY, FAT AND SOLIDS-NOT-FAT I N MILK, UPON THE BASIS OF THE SOCIETY OF PUBLIC ANALYSTS’ METHOD. BY OTTO HEHNER AND H. DROOP RICHMOND. (Read 6efore the Xociety o n December 14th, 1887.) IT will be within the memory of some members of the Society that a few years ago one OF us worked out a formula which expressed the relation between specific gravity, fat, and solids-not-fat in milk (ANALYST, vol. vii., p. 129), upon the basis of the Wanklyn process, which was then still in general use among analysts. The formula did not lay any claim to originality, for both Behrend and Morgen, and Clausnitzer and Mayer bad previously given formulz intended to express that relation.It, however, drew the attention of public analysts to the fact that there was such a relation, which formerly was by no means generally recognised. The Wanklyn process of direct extraction of fat from the milk solids being now,- THE ANALYST. 27 happily, a matter of the past, and the Adams process of fat extraction from the paper coil being generally recognised, and adopted by the Society’s Milk Committee, and by analysts in foreign countries, it appeared very desirable to work out a formula for the relation of specific gravity, fat, and solids-not-fat upon the bases of Mr. Adams) method of extraction. To every particular process of milk analysis appertains a parti- cular relation or formula.Morgen’s plaster extraction formula is not applicable t o the Wanklyn method, nor our Wanklyn formula to the coil process. This fact cannot be too strongly impressed, and has not unfrequently been overlooked by critics of the different formula. We have, therefore, taken upon ourselves to establish a mathematical expression of this relation for the coil process. The method pursued was not precisely that recommended by the Society of Public Analysts, but a slight modification, which simplifies the process. 5 C.C. of milk were pipetted into a weighed dish, and the weight accurately ascertained. From these the total solids were estimated by evaporation and drying to practical constancy. 5 C.C. of the Same milk were then dropped as equally as possible upon a strip of demy blotting paper of regulation size, the paper being pinned at one of the small edges against a frame or a bench, and the lower end folded up for about half an inch, to catch any drops which might otherwise run down and be lost.The weight of the 5 C.C. was taken to be the same as that previously ascertained. Any error which could thus occur could amount to only a milligramme or two, and would be without appreciable influence upon the result. The strips of paper were allowed to hang in the air until they were practically dry, which took generally about one hour. They were then coiled up and extracted with ether in a Soxhlet tube for at least an hour and a half. We carefully avoided drying the paper at elevated temperatures, in order to reduce any possible oxidation of the fat to a minimum.The extraction should last an hour and a half, as we have convinced ourselves that a less time is frequently insufficient. The paper coils mere not previously extracted with ether, an allowance (which amounted to -0120 grm. for each) being made for soluble matter contained in each coil, based upon careful blank experiments. The process thus simplified (after the example of Mr. Allen and Mr. W. Thomson) shows a saving of a number of weighings over the method of the Milk Committee, and rather raises than diminishes the accuracy, all chance of evaporation during the absorp- tion by the coil, and subsequent influence upon the result, being thus avoided. The specific gravities were taken by a Spengel tube with very narrow capillaries, or with an improved Westphal balance of great delicacy, procured from Messrs.Sartorius, in Gottingen . There are norma1, skimmed, skimmed and watered milk, cream, milk enriched with cream, and the same watered. We hope that no reproach can be made that the series is not a thoroughly representative one. Many of the results are the averages of two self-agreeing duplicate estimations. I n column 1 of the table are the specific gravities, marked ‘‘ Q,” being the figures beyond 1,000 ; in column 2 the total solids por cent ; in column 3 the fat por cent. The following series of milk analyses embraces milks of all descriptions.1 -- - - - G T - < ' e 4 F < f 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 - F(founi 26.1 33.1 28.7 24-2 23.8 31.3 31.0 23.1 32.0 31.0 33-4 29.7 30.4 32.9 20.6 32.3 28-4 30.6 36.8 j2.9 32.4 31.2 TABLE OF ANALYSES.10.2: 14.94 11.69 10.62 11.08 12.40 12.22 8 53 13-13 13.40 11.75 11-20 11.69 14.13 14.07 13.86 11.90 14.03 11 OQ 13.05 12-71 15.23 3.07 5.64 3.39 5-91 4.24 3.77 3.65 2.27 4.39 4 -78 2.79 3.28 3.53 5.06 5.43 5.01 3 -86 5.47 3.49 3.89 3.75 6.20 4 F (calc. from formula: 3-08 5-62 3.78 3.84 4.32 3.82 3.74 2.28 4.30 4.75 2.8 1 3.1 4 3-41 4.95 5.41 4.86 4 ~ 0 3 5 38 360 4 *03 3.S1 6-28 6 Diff. + *01 - -02 - .I1 - *07 + -08 + -05 + -09 + *01 - -09 - *03 + -02 - el4 - -12 - -10 - *02 - 615 t 017 - *09 t e l l I- -14 + *06 + *of3 I 6 F (calc. with :orrectior 3 08 5-62 3.78 3.84 4.32 3.83 3 *74 2.27 4.30 4.75 2.79 3.13 3.41 4-95 5.41 4-86 4.03 5.38 4.03 3.8 1 6.28 7 Diff.+01 - .02 - 9 1 1 - *07 + -08 + -05 + .09 - - -09 - *03 - '15 - el2 - *lo - *02 - *15 + *17 - *09 t o l l t *14 + *06 + *08 8 F & M 2-88 5-34 3-52 3.61 4.08 3.50 3.36 2.09 4-05 4-50 2.62 2.89 3-19 4.71 5.13 4.60 3.79 5.1 4 3.37 3.8 1 3.59 5 96 Diff. - -19 - -30 - *37 - *30 - '16 - *27 - -29 - -19 - -34 - 928 - * l 7 - -39 - *34 - *34 - '30 - *41 - 007 - -33 - -12 - *08 - *1G - -2429 ~. THE ANALYST. - 2: 24 2E 2E 27 28 29 30 31 33 33 34 35 36 37 38 30 40 41 42 -- 32.4 31-3 32.8 32 2 32.7 32.6 32.5 31.4 30.0 10.2 35.6 35.6 33 3 26.4 23.8 12-0 35.4 32.6 28.2 31.6 Aver, 29.75 Probable error Maximum error 12-41 11.10 13.03 12.36 12-91 13.05 13.07 13-00 14.35 30.79 9.52 9 69 9-21 7.21 19.65 10817 9*49 12.80 11.36 12.88 3.5 1 2.71 4 10 3.62 4.05 4.1 6 4.22 4.32 5 -82 24.06 *39 *43 -5 7 *23 11 63 5.98 *35 4.03 3.65 4-26 12.64 4.37 F (calc.F (calc. formula) correction) from Diff. 1 with Diff. 3.59 2 71 4.04 3.59 3-95 4.10 4.14 4.31 5.78 24.23 04 1 *56 6 4 *4 3 11 *68 6.12 *43 3-88 3.61 4.1 7 + -O€ - - -06 - *05 - * l o - '06 - -08 - -01 - -04 + 017 + *02 +*13 + *07 + 9 0 + 005 f -14 +-08 - -15 - -04 - -00 I 3.58 2.69 4.04 3.58 3.95 4.10 4.14 4 31 5.78 24.23 -35 *5 0 058 -36 11.68 6.12 -37 3 88 3 61 4.17 + -07 - *02 - a06 - '04 - .lo - -06 - *08 - *01 - -04 +el7 - *04 + -07 + . O l + *13 + .05 + -14 + -02 - *15 - -04 - *09 I 8 F & M 3.37 2.52 3.80 3.37 3 72 3.86 3.89 4.08 5.49 23.41 *30 *43 *5 2 *34 11.22 5.85 *29 3.65 3.38 3.94 Diff. - *14 -.19 - '30 - *25 - -33 - -30 - *33 - *24 - -33 - *65 - -09 __.- '05 + 11 - 041 - *13 - '06 - -38 -- -27 - *32 - '26 -6530 THE ANALYST. Hitherto all milk formula: which have been constructed have been based upon the assumption that the specific gravity of the fat contained in milk was a known quantity. Thus Behrend and Morgen assumed that each per cent. of fat depressed the gravity by 1, whilst Fleischmann, inhis new formula F -= $33 T - 2.22 loo' - '"takes the gravity of fat to be - 0'7. One of us, in his formula applying to the Wanklyn process, took the gravity of fat to be -0725, based upon results of Wigner and Blyth. But it is by no means certain that the gravity of the fat as contained in milk is equal to the gravity of the solid extracted milk-fat. The fat in milk is mostly in the fluid state, whilst separated butter-fat at 60° F is solid.S By the employment of the reasoning used by one of us in a former paper on this subject, i.e, that each per cent. of fat would lower the gravity by a certain amount (f), and each per cent. of solids not fat would raise the gravity by a certain amount (5) we get the equation- G=Ss-Ff, or as total solids (T)-F=S G=(T-F)s-Ff or Ts- G=F (s+f) F s G - 1 T s+f T s+f or-=- - -.-which is the formula to the straight line F G T T on which all our results should lie if plotted with -+-. as abscissae and coordinates respec tively . But every straight line may be expressed by the formula x = 9 . y + const. .F dx dT 1 0 - - - s + f d- T which gives the value of s + f, and substitution in equation . -- Ts-G=F ( s + f ) . .gives us s, and consequently f ; by differentiation of our results the values- are obtained which give the equation F =*859 T- 9186 G, s = 3,938 or T - 0254 G = 1-164 F. G T T On plotting the results with F as abscissae, and - as coordinates,and drawing the line F=*859 T- 02186 G, it is seen, that whilst this line well expresses the relations of gravity and fat in average milks, it does not accurately apply to extreme cases, plainly indicating that a straight line cannot express the results, and that our inital assump- tion must be incorrect. This fact might have been foreseen had we taken into account the effect. of dilution on (say) a solution of sugar, where it is well known that the law is not of a simple order, but is expressed by a parabolic curve; as our results were few at the ends of curve where the divergence from a straight line was most perceptible,THE ANALYST.31 and the errors of experiment were large, we have not attempted to work out the acbual carve, but have contented ourselves with making an approximation, which should be sufficiently near for all practical purposes ; this is- G (T“--’) T F z.859 T - 9186 G- *05 - 3 5 when - exceeds 2.5. This, as will be seen by a glance at the diagram, and at the table of analyses, (columns 6 and 7,) very fairly expresses the results on the lower part of the curve, but we have decided to apply no correction to upper part, first, because nobody would think of analysing a cream in this way, and, second, because the errors of experiment are too large, and our results too few to enable us to correct with any degree of accuracy.For average milks the formula gives results within about -02 of the other and is much easier to remember. In the annexed diagram A is the straight line F= *889 T- 02186 G B expresses the correction- *O5 C represents Fleischmann’s new formula D is Hehner’s oid Wnnklyn formula. The difference between the three methods of milk analyses is thus well seen. In column 8 of our table of analyses are given the results calculated from Fleischmann’s new formula. On the average these are *26 per cent. lower than the results by the coil process. On applying the Wanklyn formula previously referred to, we find that on the average, the direct fat extraction gives results which are *45 per cent. lower than those by the coil. But in the case of very poor skim milk the Wanklyn formula actually gives negative results, showing that that method is quite inapplicable. These calculated averages confirm in a remarkable degree the conclusions of the Milk Committee as to the relations of the results obtained by the various methods, namely, that the coil figures were 96 per cent., the plaster results from 02 to 03 per cent. lower than those by direct extraction. From our formula the following tables have been calculated, giving at a glance the fat from total solids and specific gravity for milk of widely varying composition. We would, in conclusion, strongly urge, that no milk analyses be accepted as correct which do not correspond closely with the calculated results. Reference to previous pages of the ANALYST, and to well known works on adulteration will prove how much has been sinned in this respect,

ISSN:0003-2654    

DOI:10.1039/AN8881300026

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

32 THE ANALYST. SOCIETY OF PUBLIC ANALYSTS’ METHOD OF MILK ANALYSIS. FAT CALCULATED FROM SPECIFIC GRAVITY AND TOTAL SOTADS- F= .S59 T - 9189 G - -05 (: - 2.5 ) it positive. B Y OTTO HEHNER AND H. DROOP RIcHAlOND. SPECIFIC GRAVITY. 1024.0 1024.5 1025.0 1025.5 1026.0 1026.5 1027.0 1027 5 1028.0 1028.5 1029.0 1029*5 1030.0 1030.5 1031.0 1031.5 1032.0 1032-5 1033.0 1033.5 1034.0 1034.5 1035.0 TOTAL SOLIDS. 3.35 3.24 3.13 3-03 2.92 2.81 2.69 2.58 2.47 2.35 2.24 2.13 2.02 1.91 1.80 1.69 1 5 8 1.47 1.36 1 2 5 1-14. 1.02 *9 1 3.43 3-33 3.22 3.1 1 3.01 2-90 2.78 2.67 2.55 2.44 2-33 2.22 2.1 1 2.00 1.89 1.77 1.67 1-56 1.45 1.33 1.22 111 1 *oo 3.52 3.42 3.31 3.20 3.09 2.98 2 87 2.76 2.64 2 52 2-41 2 30 2-20 2.09 1 9 7 1.86 1.75 1.64 1.53 1.42 1.30 1.1 9 1.08 3.61 3.50 3.39 3.28 3.1 7 3.06 2.95 2.84 2.73 2.62 2.51 2.39 2.28 2-17 2.06 1-95 1 -84 173 1.61 150 1.39 1.28 1.17 3.70 3-59 3.48 3.37 3-26 3.1 5 3.04 2.93 2-81 2-70 2059 2-48 2.37 2.26 2.15 2 *04 1.93 1.82 1.70 1.59 1.47 1.36 1-85 3.78 3.67 3-56 3.46 3.35 3.24 3.12 3.01 2.90 2.79 2.68 2.57 2-46 2.35 2 23 2.1 2 2.0 1 1.90 1-79 1.67 1.56 1.45 1 *34 3.87 3.76 36.5 3.54 3.43 3.32 3.21 3.10 2.99 2-88 2.77 2.65 2.54 2.44 2-33 2.2 1 2 .lo 1.99 1-58 1.76 1 6 5 1 -54 1 *43 3.95 3.85 3.74 3-63 3.52 3 41 3.30 3.19 3.07 2.96 2.85 2.74 2 63 2-52 2.41 2-30 2.19 2.08 1.97 1 8 5 1.74 1.62 1-51 4.04 3-93 3.82 3.71 3-60 3 50 3.39 3 27 3.1 6 3.05 2.94 2.83 2-72 2-61 2.49 2.38 2.27 2.1 6 2.06 1 9 5 1.83 1-71 1.60 4.13 4.02 3.9 1 3.80 3.69 3.58 3.47 3036 3.25 3.1 3 3.02 2.91 2 s1 2.69 2-58 2.47 2.36 2.25 2 14 2-03 1.91 1 9 0 1.69THE ANALYST.33 FAT CALCUL ATED-continued. 4*3( 4.1: 4.OE 3-97 3-86 3.75 3-64 3.54 3.43 3-32 3-2 1 3-10 2-98 2.87 2.76 2.64 2.53 2.42 3.3 1 2.20 2.09 1.98 1 *87 SPECIFIC GRAVITY. 4.64 4.5: 4.42 4.32 4.21 4.10 3.99 3-88 3.77 3.66 3.55 3.44 3.33 3-23 3.12 3.00 2.88 2.77 2.66 2.55 2.44 2.33 2.22 1024.0 1024.5 1025.0 1025.5 1026.0 1026.5 1027.0 1027.5 1028*0 1028.5 1029.0 1029.6 1030 *O 1030-5 1031.0 1031.5 1032.0 1032.5 1033.0 1033.5 1034.0 1034.5 1035.0 - 11.0 4.2 1 4.1C 3.9c 3-85 3-78 3-67 3-56 3.45 3.34 3-23 3.12 3.00 2-89 2-73 2.66 2.55 l-44 2.33 !-22 r.11 2-00 1.89 1 -78 TOTAL SOLIDS. 4.38 4.27 4.17 4.06 3.95 3.84 3.73 3.62 3.51 3.40 3.29 3.18 3-07 2.96 2.85 2.73 2.62 2-51 2 -40 3.29 !*18 1.07 9 5 4.45 4.3E 4.25 4.14 4.03 3.93 3.82 3-71 3-60 3.49 3.38 3.27 3.16 3.04 2.93 2-85! 2.71 2.60 2.49 2-37 2.26 2-15 PO4 4-5t 4.41 4.34 4-2: 4-12 4.01 3-9c 3.79 3-68 3.58 3.47 3.36 3.25 3-14 3-03 2.91 2.80 2.68 2.57 3-46 3-35 2-24 P13 4.7: 4-65 4.51 4.4c 4.29 4.lf 4.07 3.96 3.85 3.75 3.64 3-53 3.42 3.31 3.20 3.09 2.97 2.86 2.74 2.63 2.52 2-4 1 2-30 4.8 1 4.70 4.59 4.49 4.38 4.27 4.1 6 4.05 3.94 3-83 3.72 3-61 3-50 3.40 3-29 3-18 3.06 2.95 2-83 2-73 2.61 2.50 3.39 4.9( 4.7: 4-6t 4.55 4.4e 4.3: 4-24 4-14 4.03 3.92 3.81 3.70 3.59 3.48 3.37 3.26 3.14 3.03 2-92 2.81 2-70 2-58 2.47 -9 4.97 4.87 4.78 4.66 4.54 4.43 4-32 4.21 4.10 4.00 3.89 3.78 3.67 3.56 3.45 3.34 3.22 3.1 1 3.00 2.89 2.78 2.67 8-5634 THE ANALYST.SPECIFIC GRAVITY. 1024.0 1024.5 1025.0 1025.5 1026.0 1026.5 1027.0 1027.5 1028.0 1028.5 1029.0 1029.5 1030.0 1030.5 1031*0 1031.5 1032.0 1032.5 1033.0 1033.5 1034.0 1034.5 1035.0 FAT CALCULATED-continued. TOTAL SOLIDS.12.0 5.0: 4.9t 4.8E 4.74 4.69 4-52 4.42 4-30 4.20 4.09 3-98 3.87 3.76 3.65 3.54 3.43 3.32 3.20 3.1 0 2.98 2.87 2.76 2-65 *1 5.16 5-05 4.94 4.83 4-72 4-61 4.50 4.3 9 4.28 4.1 8 4.07 3-96 3.85 3.74 3.63 3.52 3.41 3-30 3.19 3.07 2.95 3.85 3.74 5.24 5.13 5-02 4.91 4.81 4.70 4.59 4.48 4.37 4.26 4.15 4.04 3.93 3.83 3.72 3.6 1 3.49 3.38 3.27 3.16 5.05 2.93 2.82 - 5.33 5-22 5.1 1 5-00 4.89 4-78 4.67 4.57 4.46 4.35 4-24 4.13 4-02 3.91 3.80 3.69 3.58 3.47 3.35 3-24 3.13 3.02 3-91 - *4 5.41 5.31 5.20 5.09 4.98 4.87 4.76 4.65 4.54 4.43 4.32 4.21 4.11 4.09 3.89 3-78 3.66 3-55 3.44 3.33 3.21 3.10 2-99 - - *5 5-50 5.39 5-28 5-1 7 5.06 4.96 4.85 4.74 4.63 4-52 4-40 4-30 4-1 9 4.08 3.97 3.86 3-75 3.64 3.54 3.42 3.30 3-19 3.08 - 5.59 5-48 5.37 5.26 5.15 5.04 4.93 4.82 4-71 4.60 4.49 4.39 4.28 4.17 4-06 3.95 3-84 3.73 3.61 5-50 3.39 3.28 3.16 ii__ -7 5-67 5.56 5.45 5-34 5.24 5.13 5.02 4.9 1 4.80 4.69 4.58 4.47 4.36 4-25 4.1 4 4.04 3.93 3-82 3.70 3.59 3.48 5.37 3.25 5.76 5.65 5-54 5-43 5.32 5.21 5.1 0 4.99 4.88 4-78 4-67 4.56 4.45 4.34 4-23 i-11 1.-01 3-90 3.79 3.68 3.57 3-4 6 3-35 6.85 5.74 5-63 5.52 5.41 5.30 5.19 5.08 4.97 4.86 4.75 4.62 4.53 4.42 4-32 4.2 1 4.10 3.99 3.88 3.76 5.65 3.54 5-43THE ANALYST.35 FAT CALCULATED-continued. SPECIFIC GRAVITY. 1024.0 1024.5 1025.0 1025.5 1026.3 1026-5 1027.0 1027.5 10284 1028.5 1029.0 1029.5 1030.0 1030-5 1031.0 1031.5 1032.0 1032.5 1033.0 1033.5 1034.0 1034.5 1035 *O 13.0 5.93 5.82 5.71 5.60 5.49 5.38 5.28 5.1 7 5.06 4.95 4.84 4.73 4.62 4.5 1 4.40 4.29 4.1 9 4.08 3.97 3-86 3.74 3.63 3.52 -1 6.02 5.91 5.80 5.69 5.58 5.47 5.36 5-25 5.14 5.03 4.92 4.81 4.71 4.60 4.49 4.38 4.27 4.1 6 4.05 3.94 3.83 3-72 3.61 *2 6.10 5.99 5-88 5.78 5.67 5.56 5.45 5.34 5.23 5.12 5-01 4.90 4-79 4.68 4.57 4.46 4-36 4.25 4.14 4.03 3-92 3.80 3.69 *3 6.19 6-08 5.97 5-86 5.75 5.64 5.53 5.42 5-31 5.20 5.09 4.99 4-88 4-7 7 4-66 4.55 4.44 4.33 4.22 4.1 1 1.00 3.89 3.78 TOTAL SOLIDS.6.27 6-16 6.06 5.95 5.84 5.73 5.62 5-51 5.40 5.29 5.1 8 5-07 4.96 4-85 4.75 4-64 4-53 4-42 4-31 4.20 4-09 3.98 3-87 -5 6.36 6.25 6.14 6.03 5.92 5.82 5.71 5-60 5-49 5.38 5-27 5.16 5-05 4.94 4.83 4.72 4.6 1 4-50 1.40 1.29 1.18 1.07 3-96 - -6 - 6-44 6.3; 6.2; 6-15 6-01 5-90 5-79 5-68 5.57 5-46 5.35 5-24 5.14 5.03 4.92 4-81 4.70 4-59 4.48 4-37 4-26 i.15 1.04 -7 6.53 6.42 6.31 6.20 6.09 5.99 5.88 5.77 5.66 5.55 6-44 5-33 5.22 5.1 1 5.00 4.89 4.79 4.68 4.57 4.46 4-35 4-24 i.13 7 -8 6.62 6-51 6.40 6.29 6.1 8 6.07 5.96 5-85 5-74 5-63 5.52 5.41 5.31 5-20 5.09 4.98 4.87 4.76 4-65 4.54 4.44 4.33 4.22 - -9 6.70 6-59 6.48 6.37 6.27 6.16 6.05 5.94 5.83 5.72 5.61 5-50 5.39 5.28 5.18 5-07 4.96 4-85 1.74 1.63 1.52 1.4 1 t.30 -36 THE ANALYST.SPECIFIC G R A v I T Y 1024.0 1024.5 1025.0 1025 5 1026.0 1026.5 1027.0 1027.5 1028 0 1028.5 1029.0 1029.5 1030 *O 1030.5 1031.0 10315 1032.0 1032.5 1033.0 1033.5 1034 0 1034.5 1035.0 I FAT CALCU L ATED-continued. -1 6.8t 6.7: 6-6( 6-5E 6-44 6.33 6.22 6.1 1 5-00 5-89 5.78 5.67 5.57 is46 i.35 i.24 i.13 i.02 :*9 1 .%O 4.69 1.58 4-47 -2 6.9( 6.8! 6.74 6.6: 6-52 6.41 6-31 6.2C 6-09 5.98 5.87 5-76 5.65 5.54 5-43 is32 i.22 i s 1 1 i.00 : a 8 9 :.78 :-67 :*56 -3 - 7.01 6-91 6.8: 6.7; 6.6: 6 5 6.31 6% 6.1 ‘i 6*O€ 5.95 5.84 5.74 5.63 5.52 5.41 5.30 5-19 i.08 L.97 1.86 I.75 :.64 TOTAL SOLIDS. - .5 7-21 7.1‘ 7*0( 6% 6.7f 6-6; 6*5f 6*4C 6.3E 6.24 6.13 6.02 5-91 5.80 5-69 5.5s i - P i i.36 i.26 i.15 i-04 :.93 -.82 -7 7*3! 7-24 7.1 \ 7.0t 6.9: 6-84 6.74 6-65 6-52 6.41 6.30 5.19 5-08 5-97 5-86 i.75 5.64 is53 i-42 is32 is21 i.10 r.99 *9 ‘ 15*( I DJFFERENCE TABLE. /I drri 2 9 $ &g h +.01= +.01 + -02 = + -03 + -03 = + *03 +.04= +so3 + -05 = + -04 +a06 = + -05 +.07= +*06 + -0s = + -07 -+ -09 = + *08 -- G El $ ” ’ t3 # 2 + * 1 = -*02 +.2= -*04 +‘3 = - -07 + - A = - -09 (Conclusion of the Society’s Proceedings.)

ISSN:0003-2654    

DOI:10.1039/AN8881300032

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

THE ANALYST. 37 MARGARINE ACT, 1887. AN Act for the better prevention of the fraudulent sale of margarine. Whereas it is expedient that further provision should be made for protecting the public against the sale as butter of substances made in imitation of butter, as well as of butter mixed with any such substances :- Be it therefore enacted by the Queen’s most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the authority of the same, as follows :- [Short Title.] [Commencement ofAct.1 [Dejnition.] 1. This Act may be cited as the Margarine Act, 1887. 2. This Act shall come into operation on the first day of January one thousand eight hundred and eighty-eight. 3. The word (‘ butter ” shall mean the substance usually known as butter, made exclusively from milk or cream, or both, with or without salt or other pre- servative, and with or without the addition of colouring matter.The word “margarine ” shall mean all substances, whether compounds or otherwise, prepared in imitation of butter, and whether mixed with butter or not, and no such substance shall be lawfully sold, except under the name of margarine, and under the conditions set forth in this Act. 4. Every person dealing in margarine, whether wholesale or retail, whether a manufacturer, importer, or as consignor or consignee, or as commission agent or otherwise, who is found guilty of an offence under this Act, shall be liable on summary conviction for the first offence to a fine not exceeding twenty pounds, and for the second offence to a fine not exceeding fifty pounds, and for the third or any subsequent offence to a fine not exceeding one hundred pounds.5. Where an employer is charged with an offence against this Act he shall be entitled, upon information duly laid by him, to have any other person whom he charges as the actual offender brought before the Court at the time appointed for hearing the charge, and if, after the commission of the offence has been proved, the employer proves to the satisfaction of the Court that he had used due diligence to enforce the execution of this Act, and that the said other person had committed the offence in question without his knowledge, consent, or connivance, the said other person shall be summarily convicted of such offence, and the employer shall be exempt from any penalty.[Marking of cases.] 6. Every person dealing in margarine in the manner described in the preceding section shall conform to the following regulations :- Every package, whether open or closed, and containing margarine, shall be branded or durably marked ‘‘ Margarine ” on the top, bottom, and sides, in printed capital letters, not less than three quarters of an inch square; and if such margarine be exposed for sale, by retail, there shall be attached to each parcel thereof so exposed, and in such manner as to be clearly visible to the purchaser, a label marked in printed capital letters not less than one and a half inches square, ‘( Margarine’’ ; and every person selling margarine by retail, save in a package duly branded or durably marked as aforesaid, shall in every case deliver the same to the purchaser in or with a paper wrapper, on which shall be printed in capital letters, not less than a quarter of an inch square, “ Margarine.” 7.Every person ‘dealing with, selling, or exposing, or oflering for sale, or having in his possession for the purpose of sale, any quantity of margarine contrary to the provisions of this Act, shall be liable to conviction for an offence against this Act, unless he shows to the satisfaction of the Court before whom he is charged that he purchased the article in question as butter, and with a written warranty or invoice to that effect, that he had no reason to believe at the time when he sold it [Penalty.] [Exemption from penalty.] [Presumption uguinst vendor,]38 THE ANALYST.that the article was other than butter, and that he sold it in the same state as when he purchased it, and in such case he shall be discharged from the prosecution, but shall be liable to pay the costs incurred by the prosecutor unless he shall hwe given due notice to him that he will rely upon the above defence. [Margarine imported or manufactured.] S. All margarine imported into the United Kingdom of Great Britain and Ireland, and all margarine whether imported or manu- factured within the United Kingdom of Great Britain and Ireland, shall, whenever forwarded by any public conveyance, be duly consigned as margarine; and it shall be lawful for any officer of Her Majesty’s Customs or Inland Revenue, or any medical ofher of health, inspector of nuisances, or police constable, authorised under section thirteen of the Sale of Food and Drugs Act [38 and 39 ‘CTict.c. 631, 1875, to procure samples for analysis if he shall have reason to believe that the provisions of this Act are infringed on this behalf, to examine and take samples from any package, and ascertain, if necessary by submitting the same to be analysed, whether an offence against this Act has been committed. 9. Every manufactory of margarine within the United Kingdom of Great Britain and Ireland shall be registered by the owner or occupier thereof with the local authority from time to time in such manner as the Local Government Boards of England and Ireland and the Secretary for Scotland respectively may direct, and every such owfier or occupier carrying on such manufacture in a manu- factory not duly registered shall be guilty of an offence under this Act.10. Any officer authorised to take samples under the Sale of Food and Drugs Act, lS75, may, without going through the form of purchase provided by that Act, but otherwise acting in all respects in accor- dance with the provisions of the said Act as to dealing with samples, take for the purposes of analysis samples of any butter, or substances purporting to be butter, which are exposed for sale, and are not marked Margarine, as provided by this Act; and any such substance not being so marked shall be presumed to be exposed for sale as butter. 11. Any part of any penalty recovered under this Act may, if the Court shall so direct, be paid to the person who proceeds for the same, to reim- burse him for the legal costs of obtaining the analysis, and any other reasonable expenses to which the Court shall consider him entitled. 12. All proceedings under this Act shall, save as expressly varied by this Act, be the same as prescribed by sections twelve to twenty-eight inclusive of the Sale of Food and Drugs Act, 1875, and all officers employed under that Act are hereby empowered and required to carry out the provisions of this Act. 13. The expression ‘‘ local authority ” shall mean any local authority authorised to appoint a public analyst under the Sale of Food and Drugs Act, 1875. [Registration, of manufactory.] [Power to inspectors to take samples without purchase.] [Appropriation of penalties.] [Proceedirzgs.] [Definition of local authority.]

ISSN:0003-2654    

DOI:10.1039/AN8881300037

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

38 THE ANALYST. ON REICHERT-MEISSL’S METHOD OF BUTTER ANALYSIS, AND ITS APPLICATION FOR THE EXAMINATION O F BUTTER AND BUTTER SUBSTITUTES. BY DR. RUDOLF WOLLNY. (Continued from page 11.) Experiments 227 and 225.--5 grms. butter were saponified as usual, and the soap The distillate required 28.76 C.C. deci- In a corresponding experiment, 40 C.C. of acid (3 : 10) were used, and the dis- Still larger quantities were obtained by the use of syrupy phos- decomposed with 40 C.C. of H,SO, (-45 : 10). alkali, tillate used 29.2 c.~. phoric acid (229-231).THE ANALYST. 39 It might, therefore, appear desirable to employ concentrated phasphoric acid, but since the fluid always contains a little alcohol, a quantity of butyric ether must be formed, tha larger the greater the concentration of the acid.This was confirmed by a number of experiments (228-233) both with butyric acid solution, and with butter. As alcohol oannot well be dispensed with in saponification, it becomes imperative to decompose the soap with so small a quantity of sulphuric acid that no free sulphuric acid, but only sodium sulphate with a little bi-sulphate, can be in the solution. In this case, no traoe of butyric ether can be formed. Even the concentration 1 : 10 presoribed by the Bavarian chemists, is somewhat too great, and gives rise to the formation of small quantities of ether. It was further of interest to ascertain the influence of the insoluble fatty acids con- tained in the retort upon the distillation. It was to be expected that the insoluble acids would have a considerable solvent power upon the butyric acid, and it had to be ascertained how large a quantity of it would be retained by the former.Experiment 233.-5 grms. butter were saponified, and the soap decomposed as usual. The mixture was heated for one hour in the water-bath, under a reffux con- denser. After cooling, the solid layer of fatty acid# was removed from the fluid, washed with cold water, and subjected to distillation with 100 C.C. of water, and 40 C.C. H,SO . 110 C.C. of the distillate required 6-37 C.C. deci-normal solution. The liquor previously decanted from the fatty acids waa diluted to 250 c.c., and twice 110 C.C. were distilled off; they required 21.01 and 3.85 c.c., together 84.86 C.C. ; total, 31.13 C.C. Experiment 334.-In an analagous experiment, the decomposed soap was heated for half an hour over the naked flame in an open flask, without boiling, The separated fatty acids, dktilled with water and H,SO, as before, used 6.16 C.C.deci-alkali. Experiment 235.-To the soap of 5 grms. beef fat, 100 C.C. butyric acid solution (requiring 30% C.C. deci-solution for neutralisation) were added, and the insoluble fatty acids removed, and distilled with water. 110 C.C. distillate required 2.36 C.C. deci- solution. Hence the fused fatty acids had retained 7.5 per cent. of the total quantity of butyric acid. Experiments 238 and 239.-2.5 grms. of a butter (of which 6 grms. required for 110 C.C. distillate 28.76 c.c.) were saponified, and treated, in duplicate, as usual, required 15.01 and 15.12 c.c., whilst one half of 5 grms. should have taken 14.38.Experiments 240 and 241.-5 grms. of a mixture of 60 per cent. of the same butter, and 50 per cent. of earthnut oil, treated as before, used 14.46 and 14.52 c.c., that is but very slightly more than the theory, viz., 14.38, a 6 C.C. of the volatile butter acids were retained by the fatty acids of the earthnut oil. The fact that such retention takes place is of great importance. The fatty acids separate from the soap in the form of a soft cheese-like mass, which only becomes completely fused during the latter half of the dis- tillation, The longer the condition of partial fusion continues, the larger the quantity of volatile acids retained. An experiment has previously been quoted (135) in which only 30.15 c.c., instead of 38-65 C.C.were used in consequence of complete solidification of the fatty acids having taken place. Such large differences of course can only occur in extreme cases, but it cannot be doubted that even much smaller differences of manipulation wiIl be of notable influence upon the result. Even when the opertttion is apparently conducted in an absolutely uniform manner, a clear condition of the fatty acids is not always obtained in equal times. The low results obtained by Munier (Zeitsch f. anal. chem., 21, p. 394) are probably due to this cause. It is evidently necessary to remove these inequalities, which can easily be managed by heating the soap under the condenser, by meahe of a very small flame, until the fatty acids are completely fused, and only then to commence the distillations by increasing the size of the flame.A similar result was obtained with earthnut oil (837).40 THE ANALYST. The quantities and proportions of fat and other materials proposed by Meissl have on the whole been found to be convenient, and it does not appear desirable to take a smaller quantity of fat than 5 grms. Contrary to the statement of Munier I have never found the slightest quantity of sulphuric acid to pass into the distillate. To test still further the accuracy of the general conclusions arrived at, the same sample of butter wm analysed by myself and Dr. A. Sanger, eight times by each accord- ing to the method as now perfected, with the following results :- WOLLNP. ~ANGER. 342 26.40 250 26.40 243 26.40 25 1 26.35 244 26.45 253 36-40 345 26.45 359 26.40 246 26.40 254 36-40 247 26.35 255 26-40 24s 26.40 356 26.40 249 26.40 257 26.40 The figures represent C.C.of deci-normal solution used by 100 C.C. distillate; hence 110 use 29.04, or after subtraction of 028 C.C. for correction, 28 76 C.C. The time required by the distillation is of great influence upon the result, A butter which required 26.40 C.C. when the distillation lasted half an hour, neutralised 27.2 and 27.5 C.C. when the distillation was so slow as to take 110 and 126 minutes respeotively. A difference of a few minutes only does not affect the result. The following are the sources of error of the Reichert-Meissl method :- 1. Error due to carbonic acid absorbed during saponification (may amount to + 10 2. Error due to formation of butyric ether during saponification (may amount to 3.Error due to formation of ether during distillation (may affeot the result - 5 4. Error due to cohesion of fatty acids during distillation (may in extreme cases 5. Error due to shape and size of the vessel in which the distillation is performed, The following are the details of the method now proposed :- 5 ems. of the clear butter fat are accurately weighed into a 300 C.C. flask (round form, length of neck 7 or8 c.m.,width of neck 2 c.m.), 2 C.C. 50 per cent. soda solution, which must be preserved so that carbonic acid cannot be absorbed, and 10 C.C. of 96 per cent, alcohol, are addd, and the mixture is heated under a reflux condenser for 15 minutes in a boiling water bath. The alcohol is then distilled off whilst the flask is heated for a t least half an hour ; 100 C.C.boiling water are added under due precautions, and the flask heated until the soap is completely dissolved. 40 C.C. of sulphuric acid (25 C.C. H2S0, in 1 litre) and two pieces of pumice of the size of a pea are added, and the flask is at once connected with B condenser by means of a glass tube, 7c.m. wide, and having, at a distance of 1 c.m. above the cork, a bulb of a diameter of 2-25 c.m The tube is bent immediately above the bulb upward in an oblique angle, in which direction it extends for 5 c.m., and is then again bent downward, also in oblique angle, and then connected with a condenser by means of an india-rubber tube. The flask is then heated by means of a very small flame, until the insoluble fatty acids are completely fused ; 110 C.C. are then distilled off into a graduated flask, the distillation lasting 30 minutes ; the distillate is mixed, and 100 C.C. filtered off, These are transferred into a beaker, 1 c.c, phenol-phthalein solution (.5 grms. in 1 litre 50 per cent. alcohol) is added and titrated with deci-normal baryta solution. To the volume of baryta, used one-tenth is added, and the figure obtained by blank experi- ment is subtracted; the latter should not amount to more than -33 C.C. per cent. - S per cent.) per cent .) amount to - 30 per cent.) and the time of distillation (may alter the result & 5 per cent).

ISSN:0003-2654    

DOI:10.1039/AN8881300038

出版商:RSC    

年代:1888

数据来源: RSC