1 SOCIETY OF PUBLIC ANALYSTS. THE ANNUAL MEETING of the Society will be held at Burlington House on Wednesday, the 19th inst. The Annual Dinner will take place the same evening. The customary circular, with particulars, will be sent to Members as usual. NOTE ON THE METHOD OF CALCULATING THE QUANTITY OF By A. ASHBY, M.B., F.R.C.S. THE excellent alcohol tables compiled by Mr. Hehner, and by Dr. Stevenson, give us a ready way of calculating the exact quantity of water which must be added to spirit of any known strength in order to reduce it to any other, found or wished for, by using, in conjunction with them, the formulæ I am about to propose. The analyst can thus readily state the amount of water which has been added to spirit of the lowest strength allowed by the Sale of Food and Drugs' Act Amendment Act in any adulterated sample which may come under his notice, whilst the spirit merchant can as easily calculate how much water he must mix with a spirit of any known strength in order to reduce it to any other he may desire. Let us presume that we have an adulterated sample of gin 45 under proof, and that we want to state how much water has been added to gin of the limited strength of 35 u.p. On referring to the tables it is seen that spirit of the latter strength contains 37.14 per cent. by volume of alcohol; consequently it has 62.86 per cent. of water by volume. Now let us add an unknown quantity of water to this spirit, which may be represented by X. The volume of the diluted spirit will be 100 + X; and the percentage of alcohol by volume in it will be—(100 + X): 100 : : alcohol by vol. per cent. at 35 u.p.: alcohol by vol. per cent. in diluted spirit. The latter is the strength of the spirit found by analysis, which in gin 45 u.p. is 31·4. Then = (100 +X) × alcohol by vol. per cent. found alcohol by vol. per cent. at 35 u.p. × 100; Alcohol by vol. per cent. at 35 u.p. × 100. 100; So that in the adulterated sample 18.28 parts by measure of water have been added to 100 parts by measure of gin of the lowest strength allowed by law. In the case of brandy, whiskey, or rum, it will be necessary to use the following formula since 25 under proof is the limit of reduction assigned by the Act to those spirits. Similarly, by the use of the following formule, and the alcohol tables already alluded to, the spirit merchant can ascertain how to reduce a spirit from any known strength to any other he may desire. Thus : Alcohol by vol. per cent. at present strength × 100 Alcohol by vol. per cent. at desired strength 100. Suppose, for example, that it is desired to reduce brandy from 1 o.p. to 12 u.p.; then on referring to the tables, and using the above formulæ, we shall have So that to 100 parts of brandy at 1 o.p. 14.79 parts of water must be added in order to reduce it to 12 u.p. By substituting the percentage of alcohol by weight for that by volume in the formulæ, the relative proportions by weight of spirit and water can be ascertained if desired. I am not aware whether these formulæ have been proposed before, but, at any rate, the use of them will demonstrate one of the numerous advantages to be derived from the complete alcohol tables by spirit merchants as well as by chemists. A NEW METHOD FOR THE EXAMINATION OF COFFEE. By F. M. RIMMINGTON, F.C.S., F.I.C. I THINK it will be generally admitted that the methods in use for estimating the degree of adulteration in coffee are far from satisfactory as regards definiteness and certainty, and that something more approaching to chemical accuracy is very desirable. Little has been done in this direction since the days of the Lancet Sanitary Commission. It may not be generally known to analysts that chicory, dandelion and, probably, some other substances that are used for mixing with coffee, are readily deprived of colour by a weak solution of chloride of lime (hypochlorite), and that this agent has very little action on coffee. When this method is adopted, a portion of the coffee should be gently boiled a short time in water, with a little carbonate of soda, so as to remove as much extractive as possible; after subsidence the liquor should be poured off, and the residuum washed with distilled water. When this has been done sufficiently, a weak solution of the hypochlorite is to be added, and allowed to remain, with occasional stirring, until decolouration has taken place, which will probably be in two or three hours. The coffee will then form a dark stratum at the bottom of the glass, and the chicory, a light, almost white stratum, floating above it, and showing a clear and sharp line of separation. The chicory after this operation is in a fine condition for microscopical examination, and both the upper and lower strata of the deposit can be examined for other substances. Although the lower stratum may be dark coloured, and have the appearance of coffee, other substances may be present, and should be looked for. I have recently met with a substance that is entirely new to me. as a coffee substitute that is not affected by this treatment. NOTE ON BUTTERINE. BY ARTHUR ANGELL, F.I.C., F.C.S. MANUFACTURERS have now succeeded in mixing foreign fats with butter. A large quantity of a compound called "Creamy Butterine" has recently been placed upon the market. It is a palatable article, has all the appearance and odour of a butter, and is therefore very different from the "butterines" and "oleomargarines" hitherto produced. It yields 92 per cent. of insoluble fatty acids, and under the micro-polariscope shows well-defined stellate crystals, thereby proving that some part of the compound has been fused. I may here mention that genuine butters made from scalded cream are crystalline in structure. ADULTERATION IN AMERICA. The following is the Report of the Committee of Award in the recent Competition instituted by the American National Board of Trade : SIR, : NEW YORK, Oct. 27th, 1880. FREDERICK FRALEY, ESQ., President National Board of Trade. The Committee appointed by the National Board of Trade for the purpose of awarding prizes for the best Act or Acts, accompanied by an Essay, designed to prevent injurious adulteration, and to regulate the sale of food without imposing unnecessary burdens upon commerce, have the honour to report as follows: In accordance with the resolutions under which the Committee was constituted, we have carefully examined the papers submitted in this Competition, and from these have selected as the three most meritorious Essays, with the accompanying Acts, numbering them consecutively in the order of merit as follows: "Equo Animo." "Sic utere tuo ut alienum non laedas." "Overcome Evil with Good." No. 1. The Essay and Acts having the motto, No. 2. The Essay and Acts having the motto, No. 3. The Essay and Acts having the motto, Upon opening the sealed envelopes, having corresponding mottoes, it is found that the authors of these Essays are as follows, viz.: No. 1. Motto "Equa Animo," G. W. WIGNER, F.C.S., London. No. 2. Motto "Sic utere tuo ut alienum non laedas," VERNON M. DAVIS, New York City, N.Y. No. 3. Motto "Overcome Evil with Good," WILLIAM H. NEWELL, M.D., Jersey City Heights, New Jersey. In addition to these Essays, we recommend the printing of the Essay having the motto "Cardinal Cajetan," whose author is O. W. WIGHT, M.D., Health Officer, Milwaukee, Wisconsin; and the remarks submitted under the motto "Work and Wait," by ALBERT B. PRESCOTT, Ann Arbor, Michigan. In connection with this award, the following remarks are respectfully submitted: 1. In view of the statements which for the last two or three years have from time to time been made with regard to the prevalence in this country of adulterations of food which are dangerous to health and life, and which have created so much agitation in the public mind, as to induce the National Board of Trade to establish this competition, it is |