摘要:

THE ANALYST. APRIL, 1888. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. AN ordinary meeting was held on the 14th ult. at Burlington House. the President, Mr. Allen, the chair was taken by Dr. Vieth, Vice-president. In the absence of The minutes of the previous meeting were read and confirmed. On the ballot papers being opened, it was announced that the following gentleman C. B. Gibson, analytical chemist, of Chicago. The following papers were read and discussed :- ‘ I The Iodine Absorptions combining Weights, and Melting Points of certain Fatty ‘ I Some Analyses of Yeast,” by Roland Williams. Some Analyses of Goose Fat,” by W. C. Young. u Pepper Adulteration, and Pepper Analysis,” by F. M. Rimmington. Mr. Rimmington showed a number of samples of various kinds, in illustration of his paper, and they were microscopically examined hy the members present, with much interest. His paper will be published in THE ANALYST for May, with a set of illustra- tions of the specimens exhibited. The next meeting of the Society will be held on Wednesday, t8he 11th April, at Burlington House. had been elected as a member :- Acids,” and

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DOI:10.1039/AN888130061b

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年代:1888

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62 THE ANALYST. ~ ~ ~ _ _ _ ~ ~ _ _ _ ON THE ESTIMATION OF PEROXIDE OF HYDROGEN. BY C. T. KINGZETT, F.I.C., F.C.S. (Read at the Meeting, December, 1887.) IN a report to the Chemical Society in 1880* upon the atmospheric oxidation of phosphorus, etc., I gave (in part 4) an account of some experiments relative to the esti- mation of peroxide of hydrogen, and showed that, if a dilute solution be sufficiently acidified with dilute sulphuric acid, it reacts completely upon potassium iodide in a very short space of time, as follows :- 2 KI + H,SO, + H,O, = K,SO, + 2 H,O + I,, whereas, in the presence of a moderate amount of acid only, the reaction takes place, as is well known, slowly, and it is not safe to titrate the mixture with sodium hyposulphite, therefore, until it has stood a long time.Harcourt and Esson had previously demonstrated in their study of this reaction that the amount of change in a given time varies directly (1) with the amount of iodide present, (2) with the amount of peroxide, (3) with the total volume of the solution, and (4) with some function of each of the other conditions under which the change occurs. My experiment proved that, other conditions being satisfactory, the reaction is complete and instantaneous if sufficient acid be used. The following determination will serve to illustrate to some extent the variety of change according to the amount of iodide present, and provide sufficient information as to the conditions subject to which the estimation of peroxide of hydrogen may be readily and accurately conducted. A solution of peroxide of hydrogen, of approximately ‘‘ 2-volume ” strength, was taken, and 10 C.C.added to a mixture of 50 C.C. 1 : 5 sulphuric acid, with 50 cc. of a 10 per cent. solution of potassium iodide. The iodine which was immediately liberated, required 32.4 C.C. 2 Na,S,O, solution. I had ascertained by previous trials that under these circumstances the whole of the peroxide of hydrogen is at once decomposed. Having now estimated the strength of the peroxide of hydrogen under somewhat wasteful conditions so far as acid and potassium iodide are concerned, the experiment was repeated, using in all cases 10 C.C. of the 10 per cent. potassium iodide solution and varying amounts of acid, with the following results :- Amount of acid used 10 C.C. 20 C.C.24.9 C.C. ?, 30 C.C. 28.4 C.C. ? Y 40 C.C. 30.0 C.C. ?7 50 C.C. 31.1 C.C. 77 Amount of N/10 hypo required. 17.7 C.C. (Colour returned upon standing). These results indicated that sufficient potassium iodide had not been used to obtain Accordingly the complete and instant decomposition of the peroxide of hydrogen. experiment was varied, using 20 C.C. of the 10 per cent. potavsium iodide solution. Amount of acid used. 10 C.C. 20 C.C. 32.4 C.C. 30 C.C. 32.4 C.C. 40 C.C. 32.4 C.C. 50 C.C. 32.4 C.C. Amount of N/10 hypo required. 31-7 C.C. (Colour returned). * Journ. Chem. SOC. (Trans.) December, 1880.THE ANALYST. G ;1 These results prove that, in determining peroxide of hydrogen of 2-volume strength, in order to ensure reliable results, it suffices to employ 20 C.C.of a 10 per cent. solution of potassium iodide (or 2 grms. in 20 C.C. water), and 20 C.C. of 1 : 5 sulphuric acid. It will be seen that 10 C.C. of acid wag insufficient. Other experiments showed that, in cases where 10 C.C. oE a 20 per cent. solution of potassium iodide was employed, less acid was repired. Thus, using another solution of peroxide of hydrogen (10 c.c.)- Amount of acid used. N/10 hypo required, 10 C.C. 33.9 C.C. 20 C.C. 33.9 C.C. 30 C.C. 33.9 C.C. 40 C.C. 34.0 C.C. 50 C.C. 34.0 C.C. By increasing the quantity of potassium iodide solution to 20 c.c., 30 c.c., 40 c.c., and 50 C.C. respectively the results were not altered, thus proving that 10 C.C. of 20 per cent. potassium iodide solution was sufficient quantity to use to ensure with 10 c.c, of 1 : 5 sulphuric acid the full decomposition of the peroxide contained in 10 C.C. of the solution under examination. Many series of experiments were made with solutions of potassium iodide and sulphuric acid, each of varying strength, but it is needless to multiply results in view of my present object-viz., t o indicate the quantities of potassium iodide and sulphuric acid which it is necessary to use in the pyactical estimation of peroxide of hydrogen. I recommend, when the solution of paroxide of hydrogen is stronger, to dilute down with water t o about 2-volume ktrength before conducting the estimation.

ISSN:0003-2654    

DOI:10.1039/AN8881300062

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年代:1888

数据来源: RSC

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THE ANALYST. G ;1 NOTES ON THE ESTIMATION OF MILK-SUGAR I N MILK BY MEANS O F THE POLARISCOPE. BY DR. P. VIETH, F.C.S., F.I.C. (Eead at the Meeting, February, 1888.) TWELVE months ago I brought before you the results of a number of complete milk analyses, and made some observations with regard to the analytical methods employed. I then stated that the milk-sugar was determined by means of the polariscope, and that I followed the directions laid down by Schmoeger for preparing a clear whey. In the discussion it was remarked that the results might perhaps come out different and more correct il mercuric nitrate were employed for removing albuminoids and fat, instead of acetic acid and basic acetate of lead. The method of precipitating by means of mercuric nitrate has been described in THE ANALYST, XII., p.196." I made some comparative experi- ments and found that the results were not materially influenced, but came out practically the same, whether the precipitation was effected by acetic acid and sub-acetate of lead, or by mercuric nitrate. However, I adopted the latter mode of procedure as the more simple and expeditious. According to Schmoeger, one has to precipitate with acetic acid, filter, add sub-acetate of lead, boil, cool down, replenish evaporated water, and filter again ; while, when precipitating with mercuric nitrate, the latter is mixed with the milk and the mixture brought on a filter, when clear whey runs off ready for polarisation. * See also '' Foods and Food Adulterants, U.S. Department of Agriculture, Washington, p. 113."64 THE ANALYST.The whey thus obtained is always perfectly bright, not only when poor or normal milks are under examination, but also when rich milks and even cream of the greatest possible richness are operated upon. I have experimented with cream containing up- wards of 50 per cent of fat, and still got quite clear whey. This is rather surprising, considering that such a cream cont'ains about 2.25 per cent. of proteids only, an amount which would appear altogether inadequate to encase on precipitation 50 per cent. of fat, that is more than twenty times its own weight and about thirty times its own volume. I thought it not improbable that the mercuric nitrate might perhaps have a direct action on the fat globules, such as rendering the liquid fat, of which they are composed, solid, and that in consequence of an alteration of this kind they might adhere t o the coagulum and not run through the pores of the filter. But microscopic examination did not reveal any change in the shape and appearance of the fat globules.There is one difficwlty when operating on cream rich in fat, viz., to get a sufficient amount of liquid €or polarisation. The mixture of cream and mercuric nitrate solution does not retain the character of a liquid, but attains that of a pulpy mass, its consistency increasing with the increasing percentage of fat. I am in the habit of taking 50 C.C. for the milk-sugar determination. Experimenting with a thin cream containing about 25 per cent. of fat, not sufficient whey drained through the filter to fill a 200 millimeter tube, and I had to use slight pressure to get the required quantity. With richer creams the difficulty is getting greater, and cream containing upwards of 50 per cent.of fat gave a few drops of whey only when the filter in the funnel was subjected to a pressure of two pounds. 111 such cases then it is necessary to dilute the cream with, say, an equal volume of water before precipitation. Schmoeger has found that the volume of the precipitate caused by the addition of acetic acid to 100 C.C. of milk is between 5 and 6 c.c., and in the article on the employ- ment of mercuric nitrate for preparing the whey for polarisation it is stated that the precipitate from 60 C.C. of milk occupies the space of 2.4 c.c., equal t o 4 C.C. from 100 C.C.of milk. Such statements and directions for working the process in question based upon them are rather misleading. Schmoeger worked upon milk containing something like 3 per cent. of fat, while in the other case the amount of fat varied from 3 to 5 per cent. Supposing a milk contains 4 per cent. of fat, this alone would occupy the space of 4-3 C.C. and to it would have to be added the volume of the precipitated proteids. It needs not many words to demonstrate the absurdity of once for all fixing a definite correction for the volume of the precipitate, as if this were a constant factor. Tho volume of the pre- cipitate must of necessity vary with the varying quality, and more especially richness of milk. It is a too well-known fact, to be dwelt upon in this place, that of all the milk constituents the fat is the one which varies between the widest limits.The percentage amount of the non-fatty solids is not subjected to such wide variations; and as the non- fatty solids consist of three compounds or groups of compounds, as, moreover, it has been proved, that these three constituents are in normal milks always present in very near the same relative proportion, we may expect the proteids to vary very little indeed in their percentage amount. According to my experience the limits for proteids are about 3.5 and 4.0 per cent. I believe I cannot be very wrong in assuming that thisTHE ANALYST. 65 amount of proteids, if precipitated in 100 C.C. of milk, will occupy the space of about 3 C.C. If then 3 C.C. of mercuric nitrate solution were added to 100 C.C.of milk, free of fat, or 1 5 C.C. to 50 c.c., the filtrate would for polarisation be equal to the milk employed. The reading of the polariscope would represent percentage of sugar by volume, which can easily be transformed into percentage by weight, by referring to the specific gravity. I f , however, as always will be the case, fat is present, another calculation becomes necessary. Tho percentage amount of fat is to be enlarged in the proportion of 93 to 100, the pro- duct being percentage of fat by vohme, and the amount of sugar read off t o be reduced in the proportion of hundred times specific gravity of milk (specific gravity of water = 1) to 100 minus volume of fat. The figure thus obtained represents the amount of crystallised milk-sugar, and is to be reduced by one-twentieth of its value for water of cry stallication. Supposing we have to deal with a milk of specific gravity 1.0325, and containing 3.72 per cent. of fat. To 50 c c. of this milk is added 1.5 C.C. of mercuric nitrate solution ; the whey on polar- isation indicates 5.1 per cent. milk-sugar. The necessary cslculsltions are then as follows : - An example will perhaps show more clearly the mode of proceeding. 93 : l00=3.'72: X. ~ = 4 . 0 . 103.25 : 96=5*1 : X. ~ = 4 . 7 4 . 4.74 - *24=4*50. I n case an excessive amount of fat should be present, the percentage quantity of proteids will naturally be depressed to some extent, and the quantity of mercuric nitrate solution may be reduced accordingly. But, even if this is not done, the error will be very slight indeed, as may be gathered from the fact that cream with 50 per cent. of fat still contains about 2.25 per cent. of proteids;

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DOI:10.1039/AN8881300063

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年代:1888

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THE ANALYST. 65 AN INSTRUMENT FOR CALCULATING MILK RESULTS. BY H. DROOP RICHMOND. (Read at Meeting, E'ebruary, 188s.) THIS instrument, which is based on the relation between fat, solids not fat, and specific gravity in milk, indicated in a recent paper by Mr. Hehner and myself (ANALYST, xiii., p. 26), consists of a slide rule, on one side of which a scale (1 division = 1 inch) repre- sents total solids, on the other a scale (1 division = 1.164 inches) shows fat, while on the slide specific gravity is indicated (1 division = -254 inch) ; these numbers show the relation according to the formula T - -254 G = 1.164 F. The instrument is very simple to use; the lines indicating the total solids and gravity found by analysis being placed together, the fat is immediately read off by an arrow on the other side, or, the arrow baing placed against the line indicating fat found, the total solids is coincident with the gravity found, thus saving a large amount of time besides totally eliminating all chance of error of calculation; to analysts having many milks it will be especially useful. In the construction (which has been undertaken by Messrs. Watson and Sons, of 313, High Holborn) it has not been found practicable to include the small correction recommended for poor skim milks, but the error introduced by this will only in extreme cases amount to *08 per cent, and is usually negligible.

ISSN:0003-2654    

DOI:10.1039/AN8881300065

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年代:1888

数据来源: RSC

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THE ANALYST. ~ ~ ON A S-IMPLE OF ‘;NAVY GREEN” PAINT. BY BERTRAN BLOUNT. (Read at the Neetiny Fehuary, 1888.) A SAMPLE of paint ctlled ‘( Navy Green” recently came into my hands, and a3 it seemed to be of somewhat unusual composition, I thought that a few words cmcerning i b might not be without interest to our Society. Examination of the paint soon showed that it did not consist, like the c d m o n kii,tlu of green paint, of some cheap white pigment, such as barium sulphate, calcium sulpha’e, or chalk, coloured by a mixture of chromate of lead and Prussian blue. Barium sulphate and chromate of lead were certainly present, but no Prussian blue, so that it remained to ascertain what was the blue constituent. A qualitative analysis of the paint after ignition, to get rid of the oil with which it had been ground, proved the absence both of copper and cobalt, and in another portion of the paint, which had been extracted with petroleum ether, a search made for chromic oxide, ultramarine, and indigo, met with a negative result in each case.Having thus fairly well exhausted the list of likely substances, I renewed the examination, as if it were a body about which nothing was known. The dry extracted paint was treated with water, which immediately became a beautiful blue colour with a greenish tinge, and the insoluble matter was left a pure yellow, shewing that a separation between the chromate of lead and the blue colouriDg matter had been effected. The solution was filtered and the filtrate concentrated ; coIourless crystals were observed to separate as the concentration proceeded, and on reaching dryness were present in considerable quantity, standing out quite distinct from the rest of the residue, which was blue and amorphous.It was found that the blue substance was soluble in alcohol while the colourless crystalline body was not ; they were accxdingly separated by means of it. The colourless crystalline substance proved to be merely calcium sulphate. The proportion of blue colouring matter was then determined by a method prac- tically identical with that used for its qualitative isolation, and found to be -24 per cent. on the oil-free paint, the actual numbers being as follows :- 4.2687 grms. of paint yielded -0102 grms. of the colouring matter; this gave on ignition 00032 grms. of ash.I do not suppose that the whole of this ash was from the colouring matter itself, but that rather it consisted of traces of metallic salts, which had escaped elimination in the extraction of the blue substance, the more so because it con- tained calcium sulphate, which body was abundantly present in the first extract with water, as was mentioned above. I then extracted the blue substance from the greater part of the small quantity of paint at my disposal, and tried to identify i t with some known colouring matter. It was found to be soluble in : - olphthalein. Water.-Solution neutral to litmus and methyl orange ; faintly acid to phm- Alcohol.-Solution lighter in tint than the aqueouq one for the same strength. Glycerin.THE ANALYST. 67 T7u3 original colour realpears.Glacial acetic acid.-Left apparently unaltered on eva2oration. Ether. I Chloroform. I Turpentine. Carbon disulphide. 1 Benzene. I Petroleum Ether. Heate3 with soda-Zime.-Slightly alkaline fumes, but the smell was not ammo- niacal. Treated in alcoholic solution with chloroform and caustic potash.-No smell of an isocyanide. Treated in aqusous solution with iodine c l i j s o h d in potussium iodide.---Nothing was thrown down, unless the solutions were very concentrated, when a scanty dark-brown precipitate formed on standing. It was then examined by the tables drawn up by E. Weingaerter, which are a development of the method proposed by Otto N. Witt for the separation of artificial colouring matters.* t Pursuing the plan laid down in these, the substance came out under the head of the ax0 colours, which together with erythrosin and tartrasin form one group, but in the list of them given along with the tables none oc3urs which is blue, except erythrosin which is said to be a reddish-instead of a greenish --blue, and the reactions of which clearly distinguish it from this substance ; for example, erythrosin gives off iodine when heated with strong sulphuric acid, whereas no halogen is evolved from this substance even when manganese dioxide is added.No definite result being obtained by the use of these tables, the behaviour of the substance with various reagents was observed. Sodium chloride.-None of the colour was precipitated even on saturating its I t was found to be insoluble in :- The aqueous solution was treated with :- solution with the reagent. The original coZour does not reappear.coloured vapours. coloured capours. Heat a piece of unmordantec?68 THE ANALYST. Hydrochloric acid,-Blue colour destroyed leaving only a yellowish tint ; on adding ammonia colour restored, but bleached again by excess. On acidi- fying the ammoniacal solution with acetic acid the colour was again restored, and was unaffected by excess of the reagent. The colour also reappeared on evaporation to dryness. Caustic potash.-Blue colour destroyed ; in a concentrated solution a slight flocculent colourless precipitate forms on standing. The blue colour is restored by acidulating with acetic acid even though the potash be used boiling and in excess. Ammonia.-Blue colour destroyed ; partly restored on heating or on neutral- ising with hydrochloric acid ; completely restored by the addition of acetic acid in excess.Sulphuretted Hydrogen.-Colour unaffected even on boiling. Ammonium sulphide (colour!ess).-Colour bleached. Sodium su1phite.-Colour at once bleached. On adding acetic acid and warming the colour returned, but on cooling faded again. This appearance and disappearance of the colour could be repeated several times. On boiling the solution to drive off the SO, the colour became permanent on cooling. Sodium thiosu1phate.-Slowly and imperfectly bleached even on long boiling. Stannous chloride.-Somewhat bleached ; on standing wholly decolourised. Bromine water.-Bleached ; colour not restored by stannous chloride. Calcium hypoch1orite.-Immediately bleached.Nitric acid (dilute).-Became green, and on standing yellowish ; evaporation in vacuo gave no crystalline product. If neutralised with ammonia and then acetic acid added in excess the blue colour was restored. Nitric acid (cone.)-Behaved as with dilute acid, but on heating became colourless, and the blue could not be restored by treatment with ammonia and acetic acid. Other weak acids, such as oxalic, citric, and boric, behaved like acetic and did not Albumen (white of egg).-The colour was precipitated together with excess o€ albumen on heating to the temperature necessary for coagulation. If acetic acid was added to perfect the precipitation of the albumen the colour was not thrown down. Lead acetate.-Apparently no reaction ; no product could be detected even on evaporation in vacuo and examination under the microscope.Basic lead acetate.-Colour completely thrown down as an amorphous greenish- blue precipitate. This precipitate was easily soluble in acetic acid, and it was found that the lead could be removed by sulphuretted hydrogen, and the colouring matter recovered. Silver nitrate.-Slight reduction ; when evaporated in vacuo no crystalline compound could be detected under the microscope. Mercuric chloride.-No apparent change in the cold or on boiling ; on evapo- ration a bluish-green, amorphous precipitate was formed. affect the colour.THE ANALYST. 69 Platinio chloride.-Beautiful yellow crystals, shaped like a Four-pointed star, They mere well seen under a Sulphuric acid conc. (on the dry substance).-Dissolved with the formation of were formed on evaporation in vacuo.;F in. objective. a yellow colour, becoming greenish on dilution. Behaviour of the substance as a dyestu$:- (I) Without a mordant. On cotton . . Not fast to cold water. On On wool } . . Not fast to boiling water. (3) With alumina as a mordant. On cotton . . Not fast to cold water. E: fil 1 . . Not fast to boiling water, (3) With albumen as a mordant. On cotton . . Not fast to cold water. On On wool ] .. . Not fast to boiling water. (4) In a bath made slightly acid with acetic acid. On cotton . . Not fast to cold water. On silk . . Fast to boiling water ; fairly fast to warm soaping. On wool . , Fast to boiling water ; not fast to warm soaping. I have been unable, from lack of material, to prepare and purify in quantity sufficient for an ultimate analysis, the only crystalline compound I have obtained, viz., the platinum salt, nor can 1 throw light on the proximate composition of the body, but I hope that the empirical reactions I have detailed may suEce for its identification. I may say that having failed to find a description of a colouring matter which tallied with it, I sought to learn its commercial name from the vendor, but found that he only knew it as '' Mid Zinc Green," under which lucid title he received it from a German manufacturer. (Conclusion of Societies' Proceedings.)

ISSN:0003-2654    

DOI:10.1039/AN8881300066

出版商:RSC    

年代:1888

数据来源: RSC

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THE ANALYST. 69 ON ADULTERATED LARD. BY STEPHEN P. SHARPLES, STATE ASSAYER, MASSACHUSETTS. IN the interest of pure food the testimony of Mr. N. K. Fairbanks and Mr. Webster, before the Committee on Agriculture of the United States Senate, should have wide circulation. They testified " that all of the lard on the market marked ' Prime Family Refined Lsrd,' ' Choice Refined Lard,' and other brands of this nature is mixed with more or less beef stearin and cotton-seed oil." As it is well known that cotton-seed oil is a semi-drying oil, having strong siccative properties at the temperature of 212" F., this admixture unfits the lard for many uses. It is impossible to make good biscuits with such a compound, as they rapidly bacome rancid. The above gentlemen represent two of the largest firms in the so-called '' refining " business in Chicago.70 THE ANALYST.The refining of lard consists solely in adulterating it with cotton-seed oil and oleo- stearin. These mixtures may be easily detected. The usual tests for detecting cotton-seed oil in olive oil answer every purpose. Bechi’s test, as given in THE ANALYST, gives good results. Lard is without action on the solutions used. Nitric acid of 1.35 specific gravity gives only a faint colour with pure lard, with lard adulterated with cotton-seed oil i t gives a colour more or less intenss, varying with the quality and quizntity of the oil used. For the beef stearin the best test is that proposed by Dr. Belfield, of Chicap, as follows:- The suspected lard is dissolved in ethylic ether, so as to form a nearly saturated solution.This is best done in an ordinary five-inch test tube, which should be about two-thirds filled with the mixture. The top of the tuba is then loosely stopped with cotton wool, and it is placed in a quiet place, a t a temperature of about sixty degrees, and allowed to stand until crystals commence to form. These crystals are removed from the tubs with a dipping tube and placed on a microscope slide ; they are quickly covered with a thin cover-glass, pressed enough to flatten the grains, and then examined with a quarter-inch objective. These are sometimes in radiated groups, but often occur singly. Beef fat always crystallises in radiating tufts, often resembling wheat-sheaves, and the crystals are either pointed or else have nearly square terminations. They are always, however, much more slender than the lard crystals. Watering lard has almost become one of the lost arts, only one sample from nearly a hundred examined had any marked amount of water; this one, however, had over forty per cent. Pure lard gives large flat plates with well-defined oblique termination$. It was kept in combination by means of an alkali.

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DOI:10.1039/AN8881300069

出版商:RSC    

年代:1888

数据来源: RSC

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THE ANALYST. _ _ _ _ _ _ ~ 70 --__ MONTHLY RECORD OF GENERAL RESEARCEES I N ANALYTICAL CHEMISTRY. A. B. TAYLOR. Am. Journ. Pharm.-A new application of an old rule has suggested a method of finding the specific gravity of liquids, which the author has never seen mentioned, and which from its simplicity and great ease of application seems worthy of publication. It is known that the weight of a body is to its specific gravity as its loss of weight when immersed in a liquid is to the specific gravity of that liquid. For example :--200 grains of citric acid (sp. gr. 1.60) lose in weight 115 grains when weighed in oil ; and as 200 is to 1.60, so is 115 to -920 the sp. gr. of the oil. Now if we make the weight of the citric acid the same number of grains as its specific gravity our formula becomes-as 1.60 is to 1.60, so is the loss in weight of the citric acid when weighed in oil t o the specific gravity of the oil ; or, in other words, the loss of weight is equal to the specific gravity ; from which we deduce the following general rule :- The specific gravity of a liquid is equal to the loss of weight (in grains) sustained by a solid body when immersed in the liquid, the weight of the solid being equal (in grains) to the specific gravity. Hence it is necessary only to weigh the solid in the liquid, and its loss gives a t once the specific gravity of the liquid.%king the preceding AN EASY METHOD OF FINDING THE SPECIFIC GRAVITY OF LIQUIDS.THE ANALYST. 71 example :-If 200 grains of citric acid lose 115 grains, 1.6 grain will lose -920 grain, and this loss is equal to the specific gravity of the oil.I n practice the weight of the solid might be 10 or 100 times the weight of its specific gravity, care being taken to put the decimal point in the right place in the final result. As perhaps one of the most desirable solid bodies to use, the author suggests a piece of aluminium weighing 256 grains; the specific gravity of that metal being 2.56. If upon trial its specific gravity should vary from these figures, its weight should be made to correspond. For liquids having greater specific gravity than 2-56 it would be necessary to us0 a heavier solid than aluminium. W. €1. D. DETECTION AXD ESTIMATION OF ROSIN OIL IN BXINERAL OIL. L. STORCH. Ber. Chem. Ind., ix., 93.-To test for rosin oil the author takes 2 C.C. of the sample and shakes it up with 1 C.C.of anhydrous acetic acid, and gently warms it. He then cools, removes the acetic liquid by means of a pipette, and adds to it a drop of strong sulphuric acid, when a brilliant red colour i g immediately produced if rosin oil be present. Owing to the presence of cholesterin in many fatty oils they give a similar reaction, and, there- fore, the absence of such oils must be first thoroughly proved. For the estimation of rosin oil in mineral oil (in the assured absence of fatty oils) the author proceeds as follows :-lo grammes of the sample are taken, gently warmed with 50 C.C. of alcohol of 96 per cent., the whole is well shaken and allowed to cool, The liquid having separated into two layers the alcoholic stratum is transferred to a tared flask, and the surface of the petroleum layer having been washed with a few C.C.of alcohol, and the washings added to the bulk, the flask is placed on the water-bath. The contents are thus gently boiled down and the evaporation is continued until the residue in the fiask is observed to be free from bubbles, when it is cooled and weighed. This residue is rosin oil with a certain amount of mineral oil still remaining (residue A). This residue is then extracted with ten times its weight of similar alcohol exactly in the same manner, and another weighed residue (B) is obtained. This second residue is now almost free from mineral oil. By now deducting the weight of alcohol used in experiment B from that taken for A, and also deducting residue B from residue A, it is evident that the exact solubility of the mineral oil in the alcohol employed can be determined, and a final correction made.For example, in a case where 10 per cent of rosin oil was actually present, 50 grammes of alcohol were used for A and 15.5 grammes for B; giving a dif- ference of 34-5 grammes. Residue A weighed 1.5136, and residue B weighed 1.1584; difference = -3552 gramrnes of mineral oil, dissolved by 34.5 grammes of alcohol. There- fore, the 15.5 grammes of alcohol used for B really ought to have dissolved ~1595 of mineral oil. This correction, deducted from residue B, leaves -9989 gramme for the weight of rosin oil present, or over 9 per cent of the weight of the sample taken for analysis. Had residue B been taken without correction it would have shown 10.32 per cent.so that the truth lies between the two results. W. H. D. ESTIMATION OF TANNIN. F. GANTTER. Ztitsc7w. J Anal. Chernie, vol. vi., 1887 -The usual process is to titrate a known volume of the solution with permanganate, and then another portion, after first removing the tannin by means of hide powder. The72 THE ANALYST. ~~ ~ use of this substance being inconvenient a proposal has been made to replace it by ferric acetate. The author has made a series of experiments to test the accuracy of the new process. If the process with the hide powder is a t all trustworthy (which is, however, questionable) the new proposal cannot be entertained. When the materials are very poor in tannin, and when, in consequence, a large quantity is weighed out, the differences are not so very great-about 1 per cent., but in the case of rich materials the results differ from 5 to 11 per cent.L. DE K. ESTIMATION OF LEAD IN ALLOYS OF TIN. Y. SCHWARZ. Chem Zeit. 4, 1888.- One gram, of the thinly flattened alloy is gently heated with 20 C.C. of concentrated hydrochloric acid. Without troubling about any undissolved spongy metallic mass, bromine is added until the liquid turns yellow, when everything will have dissolved. The excess of bromine is now boiled off and the liquid diluted up to 100 C.C. This, after cooling, is slowly poured into a solution of 40 grammes of crystallised sodic sulphide in 150 C.C. of water. After the plumbic sulphide has settled, it is filtered off and washed with weak solution of ammonic sulphide (1-10).The filter and contents are now heated, with the usual precautions, in a porcelain dish with a mixture of nitric and sulphuric acid, to make the plumbic sulphide into sulphate, which may then be washed with proof-spirit and collected and weighed as usual. It should be completely soluble in an alkaline solution of ammonic tartrate. If it leaves a residue of stannic oxide, this must be weighed and deducted. The tin is generally dissolved in about half an hour. Its weight should not exceed a few milligrammes. L. DE K. DETECTION OF ADULTERATED GROUND BONES. E. HEIDEN. Chem. Zeit., ii., 1328. -Ground bones are frequently made from bones that have been deprived of their gelatine by boiling. I n this way the nitrogen is lowered, and the phosphoric acid unduly increased.To remedy this the manufacturer often adds scraps of hoofs and similar nitrogenous matters and, at the same time he puts in sand or gypsum to bring the amount of the phosphoric acid within normal limits. The author has applied a similar process to that employed for the detection of alum in flour, viz., by shaking the suspected sample up with chloroforrn. When this is done the genuine bone powder sinks to the bottom, while the spurious additions float. No genuine sa.mple of ground bones will show more than 5 per cent. of floating particles. W. H. D. ANALYSIS OF BLACKING. V. H~LBLING. Zeitschr. f. angew. Chenaie. IVO. 1.- Analyses of apparently very simple mixtures, like blacking, give, as a rule, more trouble to analysts than delicate investigations.It will, therefore, no doubt, be interesting to them to read the author’s process. A weighed portion of the sample was boiled with water; the residue collected on a weighed filter and washed until the filtrate was colour- less, After drying and weighing the filter was exhausted in a Soxhlet’s apparatus with petroleum spirit. After evaporating the latter the residual fat was weighed. The filter and contents were burnt to ash, and the total carbon was thus found by difference. This carbon is a mixture of carbon derived from animal charcoal, and ditto formed by the action of the sulphuric acid on the sugar. A fair idea of the quantity of the firstF O THE ANALYST. / a may be got by the estimation of the calcic phosphate as the ratio between tricalcic phosphate and carbon in bone-black is generally as 9 to 1.The ash was estimated in a separate portion of the sample and further analysed by the usual processes, the chief constituents being lime, soda, iron, phosphoric and sul- phuric acids. The fat was saponified with potash and the mineral oil extracted by agitating the fluid with petroleum spirit. By titrating back the excess of alkali the saponification equivalent of the fat was obtained, which threw some light upon its nature, The watery extract was diluted up to a definite bulk, and in an aliquot part, the sugar was gravimetrically estimated by Fehling's solution. Glycerin was first qualitatively tested for as follows: 2 drops of the liquid were mixed with 2 drops of phenol and 2 drops of sulphuric acid, then heated up to 120" C., and, after cooling, dissolved in ammonia. The quantitative estimation is best performed by the process of Becke and Mayer (Zeitschr.f. anal. Chemie, 1880, 291). If more than 1 or 2 per cent. of iron has been found this points to the use of ink (tannate of iron). A portion of the watery fluid is acidified with hydrochloric acid, and repeatedly agitated in a separating funnel with acetic ether, which dissolves the tannin. This solution is then poured on some water, and the ether expelled by heat. I f tannic acid should be present it is best estimated by the well-known process with potassic permanganate. The result of the analysis of one of the samples submitted t o the author was as follows :- Water, 12-36 ; free sulphuric acid, 1.38 ; glycerin, 3.45 ; invert sugar, 10.49 ; mineral oil, 4.02 ; neatsfoot oil, 4.89 ; total carbon, 12.63 ; lime, 16.06 ; sulphuric an- hydride, 10.04 ; phosphoric anhydride, 12.65 ; oxide of iron, *84 ; soda, 5-78 parts.The phosphoric anhydride corresponds with 32.82 bone-black, or 3.28 carbon. This leaves 9.35 carbon, corresponding with 28.05 of sugar, thus making a total of 38.54 of sugar. Taking the composition of molasses as constant (24.7 per cent. of sugar), this will then represent 156.03 parts of original molasses. To char the sugar to the extent found 44.22 parts of sulphuric acid must have been required (according to the equation : C,H,,O, + 3H,S04 = 5C -t- GO,+ 2S0, + 8H,O), the total amount of the acid, therefore, being 44.22 parts. The soda (which in practice is added after the other ingredients have been mixed, to stop further action of the acid), is equivalent to 9.88 parts of caustic soda.The composition of the sample may, therefore, be fairly given as: bone-black, 33 ; molasses, 156; oil of vitriol, 44 ; mineral oil, 4 ; neatsfoot oil, 5 ; glycerin, 3.5 ; caustic soda, 10. Corresponding quantities of these must be calculated to fat. The author does not, of course, claim If glycerin is present the solution will be of a carmine red colour. The fat is sometimes decomposed into fatty acid and glycerin. absolutely accurate results. L. DE K. ESTIMATION OF STARCH BY MEANS OF IODINE. F. SEYFERT. Zeitschr. f. angew. Chernie. No. 1.-The author found the true formula of iodide of starch to be (C24H40020)61,, and has based upon this fact a volumetric estimation.1 gramme of the finely-ground flour is heated with about 150 C.C. of water for two hours in a water-bath, which will cause the starch to gelatinise. After cooling the liquid is introduced into a 500 C.C. flask and mixed with 50 C.C. of deci-normal iodine. 20 C.C. strong hydrochloric acid are'74 THE ANALYST. - added, and ths whole diluted with water up to the mark. After the iodide of starch has completely settledan aliquot part of the clear liquid is taken off with a pipette and titrated with sodic hyposulphite. The difference in iodine is multiplied by 4.37 to get the corresponding amount of starch. I n one sample of dried potato-flour the amount of starch found was 73.9 per cent. The same The test experiments are encouraging. sample, when analysed by the baryta process, gave 73.6 per cent.L. DE K. ESTIMATXON OF MANGANESE IN CAST IRON. C. REINHARD. Zeitschr f. angew Chemie, No. 4.-The author recommends the following process for samples, poor in manganese, but rich in silicon. About 3 grammes of the sample are dissolved in about 40 C.C. HCI, with addition of some potassic chlorato. After evaporating to about 20 C.C. the liquid is diluted with water, filtered into a 500 C.C. flask, and the residue well washed. Zinc oxide suspended in water is now added until the iron is completely precipitated, and after cooling, the whole is made up to the mark, and filtered. An aliquot part (say 250 c.c.) is now mixed with a little sodic acetate, and boiled with a little zinc oxide and bromine water.The manganese separates as MnO,, and is finally titrated with oxalic 15 C.C. of nitric acid are added, and the liquid boiled for some time. acid as usual. L. DE K. ESTIMATION OF CAUSTIC -ALKALIES IN PRESENCE O F ALKALINE CARBONATES. ISBERT AND VENATOR. Zeitsc?brf. angew Chemie, No. 4.--The usual plan is to first titrate with standard acid, and then again, after precipitating the carbonate with baric chloride, As, however, the percentage of caustic alkali is generally found too low by this process the authors adopt the following plan : A weighed or measured quantity of the sample is diluted and titrated in the cold with normal acid until the fluid turns distinctly yellow, an alcoholic solution of rosolic acid being used as indicator. The amount of the caustic alkali is now calculated. To find the quantity of alkaline carbonate, the same fluid must now be boiled, with occasional addition of normal acid, until the yellow colour no longer changes to red. From the extra amount of acid used, the alkaline carbonate is calculated as usual. L. DE K. A NEW PROCESS FOR THE ESTIMATION OF ALCOHOL. B. R~sE. Zeitschr f. angew Chemie, fVo. 2.-If potassic permanganate is added to alcohol, mixed with dilute sulphuric acid, an imperfect oxidation takes place, even if the mixture is heated. If, however, very dilute alcohol is first mixed with large excess of permanganate, and then suddenly with about one-third of its volume of sulphuric acid, the alcohol instantly and completely oxidises to carbonic anhydride and water. Water may now be added, and the excess of permanganate titrated back with potassic tetra-oxalate. From the amount of permanganate decomposed, the alcohol can be readily calculated, 8.244 grammes of permanganate equal 1 gram. of alcohol. The test analyses, four in number, are very satisfactory. Further experiments are promised. L. DE I(.

ISSN:0003-2654    

DOI:10.1039/AN8881300070

出版商:RSC    

年代:1888

数据来源: RSC

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TLIE ANALYST. 75 MONTHLY RECORD OF ANALYTICAL RESEARCHES INTO DRUGS. ASSAY OF COLCHICUM sEED.-Jour. de Phar. et de Chem. A. KREMEL.-TO determine the amount of colchicine, 20 grams. of the unbruised seeds are exhausted with76 THE ANALYST. alcohol, in a displacement apparatus. After boiling for two hours, the alcoholic liquor is poured into an evaporating dish, with the alcohol used in washing the receiver, and 25 ccm. of water. The residuum after evaporation-10 to 15 ccm.-is filtered and exhausted with chloroform, which takes up the colchicine. It is again dissolved in chloroform, which is finally evaporated in a water-bath. The chloroformic extract is treated with water to disassociate the combination C,,H,jNO,+ f?CHC'I, which has formed ; and is then evaporated to dryness.W. H. D. ESTIMATION OF CARBONIC ACID IN MINERAL WATERS. W. BORCHERS. Zeitsc7~r. f. Anal. Chemie, vol, vi., 1887.-The author published in 1878 his process for the estimation of combined, semi-combined, and free carbonic acid in waters." The two latter were estimated by simply boiling the sample and absorbing the liberated CO, in suitable tubes. The combined CO, was then expelled by hydrochloric acid, and also estimated. The process did not, however, work well if the water contained much sodic or potassic bicarbonates, as the excess of carbonic acid is but slowly expelled from these compounds. This may, however, be overcome by first adding to the water a little baric chloride. Baric bicarbonate is formed, which quickly loses its excess of UO, on boiling.L. DE f(. DELICATE TEST FOR XORPIIINE. J. L. ARMITAGE. Ylharm. J. 924, 127.-When a solution of ferric chloride is added to a solution of a salt of morphine a bluish-green coloration is produced. A t the same time, in consequence of the reducing power of morphine, a part of the ferric chloride is reduced to the ferrous condition, as shown in the following equation :- 3 Fe,CI, + 2 H,O = 4 FeCI, + 4 HCl + 0,. There is, however, a point of dilution (apparently about 1 in 2,000), at which the coloration is imperceptible, though the reaction represented in the above equation appears to take place even in the most dilute solutions. On this reaction is based a delicate test for morphine and its salts in solution, for if such a solution be treated with ferric chloride and then with ferricyanide of potassium, the latter will interact with the reduced ferrous chloride with the formation of Turnbull's blue, which appears either as a deep blue precipitate or greenish-blue coloration, according to the strength of the solution of the alkaloid.I n a solution of one part of a salt of morphine in 20,000 parts of water, the coloration is intensely green, and in a solution of one part in 50,000, the shade is still deep, though lighter. A solution of 1 in 100,000 gives the same result on standing a few moments, the coloration, even in this dilute solution, being unmistakable. Other reducing substances would, of course, give the same results, but in the absence of such substances the above is a delicate confirmatory test for the presence of morphine. Several other alkaloids submitted to the above test did not give the coloration. This reaction might be made the basis of a colorimetric process for the approximate estima- tion of morphine in very dilute solutions. W. H. D. * Joi6r.f. Pract. Cllemie, 17.

ISSN:0003-2654    

DOI:10.1039/AN888130075b

出版商:RSC    

年代:1888

数据来源: RSC

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77 THE ANALYST. REVIEW. ORGANIC ANALYSIS: A MANUAL OF THE DESCRIPTIVE AND ANALYTICAL CHEMISTRY OF TITATIVE ANALYSIS OF ORGANIC MATERIALS, COMMERCIAL AND PHARMACEUTICAL ASSAYS, THE ESTIMATION OF IMPURITIES UNDER AUTHORISED STANDARDS, FORENSIC EXAMINATIONS FOR POISONS, AND ELEMENTARY ORGANIC ANALYSIS. By ALBERT B. PRESCOTT, Ph.D., M.D., .Director of the Chemical Laboratory in the University of Michigan, etc. THIS is the American ‘& Allen,” and, on seeing the title, some of our readers will doubtless expect a critical comparison of the two works. I n this they will, however, be dis- appointed, because, after a most careful study of both books (with, we confess, such an intention) we have seen that each has its own idiosyncrasies and shortcomings, while, a t the same time, each has its own specialties and perfections.For ex+mple, the very first thing that strikes the reader on opening this book is that the author has adopted the dictionary arrangement, as distinguished from the classified one followed by our English author. On this point alone, when two such doctors differ, who shall decide ? For Dr. Prescott’a method of putting the matter it may be said that one can at once find what he wants to read, while Mr. Allen may reply that by the alphabetical method, all connection between the various members of the same groups of bodies is apt to be severed. Although the actual contents of both works cover pretty nearly the same ground, yet the two authors go to work so differently that the whole of Dr. Prescott’s book is compressed into one volume of 520 pages.Here again opinions will differ, some preferring the short diction and frequent absence of detail, characterising the American, while others will like the more extended and precise style of the British author. Which book a man should buy will, therefore, evidently depend on his own taste; but we ourselves are sufficiently patriotic to give the preference to our home production, as a more thorough and compendious treatment of the subject, so far as it has yet developed itself in the two volumes at present published. At the moment, Dr. Prescott’s book comes before us complete, while we still await the conclusion of Mr. Allen’s work, and, besides this, Dr, Prescott has the advantage in having been better able to present us with the recent advances in all the subject than is in the power of our English author, whose volumes only appear a t such long intervals that, in the present days of such rapid extension of the powers of analysts in dealing with bodies hitherto looked upon as almost beyond their means, the first volume is apt to be somewhat antiquated before the last appears.We hope that the publication of this book will be a stimulus to the more rapid production of our British manual. Dr. Prescott’s book is tt distinct compilation (although an able one), and we look in vain for the amount of original research by the author himself that characterises Mr. Allen’s work. On the other hand all the sources drawn upon are very plainly stated and full references are given to the original papers quoted.Having thus put our readers in possession of the relative styles of the two works, we must leave the issue in the hands of the buying public, only repeating that if our British author would only make some more speed, there would be very little room €or this work in the home market, Some very good remarks in the preface on the subject of the extension of this branch of chemistry (so interesting to us as public analysts) are worth reproducing :-&‘ Respecting the assumed peculiarities of organic analysis, it more and more appears that the differences CERTAIN CARBON COEiIPOUNDS IN COMMON USE, FOR THE QUALITATIVE AND QUAN- New York: Van Nostrand.1s THE ANALYST. between inorganic and organic analysis have been greatly overstated, just as, a t earlier periods, the distinction between inorganic and organic chemistry in general was over- drawn.With nearer acquaintance it is seen that the limits of error in determination of carbon compounds are by no means always wider than those in the analysis of metallic bodies. Organic analysis, as the determination of the unbroken compounds of carbon, no longer has an uncertain place in chemical learning.” LAW NOTES. TO OUR READERS‘. Some years ago it was decided to discontinue the reporting of orclinarypolice- court proceedings, and only to give such cases as ccuthoritatively established some point in connecti’on with the working of the acts in which public annlystt? ure interested. After a f a i r trial of this system, a majority of the members of our Society have expressed a wish that our old practice should be, to some extent, returned to, and, in deference to such request, we have decided to resume the reporting of police proceedings.The Line will be drawn at accounts of ordinary cases and reports will only be inserted when any novel, legal, or chemical point arise$, or where the certijcate of the analyst i s in any way attacked. Any member o r subscriber connected with such a case, i s therefore invited to furnish us with a report of the proceedings signed with his name, not for publication but as a guarantee of exactitude. GELATINE vewus ISINGLASS. ON the 13th March, Mr. Latimer Pfander Swinborne was summoned before the Lord Mayor for an infringement of the provisions of the Merchandise Marks Act of 1887, by having applied to certain goods-namely, gelatine or other substance-a false trade description as to the material of which such goods were composed, by which description the goods were falsely described, stated, or indicated to be isinglass.The defendant pleaded “ Not guilty.” Mr. Besley and Rfr. Gray appeared for the complainants ; Mr. Poland was counsel for the defence. Mr. Besley, in opening the case, said this was a proceeding instituted by Messrs. Gridley and Go., isinglass merchants, of 4, Bishopsgate Avenue. On February 6th twelve packets of the goods in question were sold a t the defendant’s premises in St. Andrew’s Hill, Queen Victoria Street, the label on the packets stating “ by royal letters patent.” The learned counsel pointed out that no patent existed after the lapse of fourteen years, and as far as he was instructed the only patent which would warrant that statement was one granted provisionally in the year 1847, and completely registered in 1848.He was not aware of any subsequent patent, but as far as the evidence was before him there had been no patent since that time. That patent had reference to the manufacture of gelatine, and isinglass was not mentioned in it, but only an isinglass cutter. The goods in question were described on the labels as ‘‘ Swinborne’s patent refined isinglass,” and it was asserted on the part of the prosecution that this was a false description of the contents. It was alleged in the summonses that it was not isinglass, but gelatine, and that there was not a patent exist- ing which would cover anything like the description.Isinglass wm manufactured fromTHE ANALYST. 79 the swimming-bladdera of sturgeon and other fish. Upon an analysis of a packet of the goods in question not a particle of isinglass was found, but it was gelatine. Isinglass was marked to a certain extent by non-solubility, and gelatine by solubility. Gelatine might be made from hides or undressed skins. Professor Attfield deposed that he analysed one of the packets in question. I n his opinion the substance was not isinglass but ordinary soluble gelatine. Among other differences, the insolubility in warm water of isinglass as contrasted with the solubility of ordinary gelatine was considered by him to show that the material was ordinary soluble gelatide and not isinglass. The witness was cross-examined at length by Mr.Poland as to the composition of isinglass and gelatine. He admitted that the word ‘‘ patent ” indicated that it was not isinglass, isinglass being a natural substance. Dr. Hake, of Westminister Hospital, also gave evidence to a similar effect. It was stated that when the summonses were served upon the defendant he read them and said, ‘‘ This was threshed out in 1851.” Mr. Poland, at the conclusion of the evidence, submitted that no case had been made out by the prosecution. The Lord Mayor, interposing, said he did not think it would be necessary to hear the learned counsel. He did not consider that the prosecution had made out their case, nor did he think it one that c a ~ e within the letter or spirit of the Act. The word ‘( isinglass,” by the evidence, was evi- dently a term which had been used as applied to gelatinous matters, and it was admitted by many authorities that isinglass was the purest form of gelatine.Professor Attfield, in his evidence, had admitted that the word (‘ patent ” on the packet proved that it could not be isinglass, which was a natural substance, and, if so, they could no more have patent isinglass than they could have a patent pear or a patent apple. Mr. Besley said he should like to have the question of law reserved for the opinion of the High Court. Mr. Poland said that ever since 1847 they had described this article in this way. I n 1851 the validity of the patent was called in question, and it was then described to be n most valuabh patent. I n 1853 Mr.Swinborne took proceedings against some other persons, and the Master of the Rolls then said that the plaintiff, Mr. Swinborne, was possessed of a patent for the manufacture of isinglass. They had always described it in this way. The Lord Mayor observed that they could not have a stronger proof that he was right than the fact that a judge had described it as isinglass. Therefore the term as a general term was perfectly correct. The summonses were accordingly dismissed. Isinglass was chemically one form of gelatine. How THEY TREAT (‘ MARGARINE” SELLERS ABROAD.--“ A butter merchant in Lisieux in France was charged, in the early part of February, with having sold as butter, mixtures containing according to analysis between 25 and 40 per cent. of margarine. It was sold as ‘ pure Normandy,’ ‘ unequalled,’ or ‘ choice butter.’ He was sentenced to three months imprisonment, a fine of 3000 francs and full costs.20,000 pounds of the mixtures were confiscated. The sentence to be published in twenty named papers, and notices to be posted on the doors of the town-halls and market-places of three towns on three consecutive market days.”80 THE ANALYST. €€ow A HAWKER OF MARGARINE CAN BE D E m r WITH IN BBITAIN.-A very interesting case has been decided at the Assizes in Essex, which may be thus summarised. A private person prosecuted a hawker, and had him committed for trial for obtaining money under false pretences, by selling to the said prosecutor margarine as butter. The prisoner was found guilty and sentenced to six months imprisonment, and the Judge told him that if he did it again he would send him to penal servitude. We are endeavouring to get an authoritative report of this trial, and will, if successful, publish the same in an early number. -._ - -_ - . ~VR. BURRELL (Cork) sends us the full report of a case (OConnel I ) . Kemp), where themilgistrates have fined a man $2 for selling what was admitted to be a mixture of 25 per cent. of coffee with 78 per cent. of chicory, although contained in a tin with a declaratory label. The I/ravanLcis of the decision lies in the fact that, in the view of the Court, the label was fraudulent, because while the words ‘‘ East India pure coffee ” were in bright and distinct letters, those following, namely, ‘‘ specially blended with cnltivated chicory” were in very dull letters which scarcely any one could read. An appeal was intimated, the result of which (if persevered in) will be awaited with interest.

ISSN:0003-2654    

DOI:10.1039/AN8881300077

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

80 THE ANALYST. CORRESPONDENCE. To tlbe Editor of the ANALYST. SIR,-I enclose herewith a copy of my report on the Ottawa water supply, made to the Department of Agriculture. The source of the water supply is the Ottawa River, the water of which is not subjected to any filtering process before entering the city mains. Last summer there was an exceedingly and exceptionally small rainfall, and to this may be ascribed, I believe, the presence of the large quantity of dissolved vegetable matter now found in the water. An anaiysis of this water, made in 1881, by Dr. Baker Edwards (Montreal) showed it to be an exceptionally pure water. Among the sources of Canasan water supplies we may notice three more particularly : (1) That of the large lakes, ag., Lakes Ontario, Huron, Michigan, and Superior, to which, apparently, the English standards are applicable ; (2) That, of the rivers, e.g., Ottawa, which flow through densely wooded districts, and which i t would not be wise to judge of with rigour by the English standards, as they necessarily contain more dissolved organic matter of a vegetable origin ; and (3) That of springs, the water of which differs greatly from either of the preceding, both as to organic and mineral con- stituents. The waters of the second class above named will be very apt to vary in quality according to the season of the year, and I have pointed out the necessity of a systematic and periodical examination, in order to ascertain, if possible, the normal condition of this water.As a word of vaison d'etre for the late examination I would say that the City of Ottawa has, during the last three months, been visited by a severe epidemic of typhoid fever, for the cause of which many theories have been promulgated, some ascribing i t to the water and others to defective drains.The good work which the Society of. Public Analysts inaugurated in England for obtaining greater uniformity in methods of water analysis, and consequently, for the interpretation thereof, has already started here, and valuable data have lately been brought out by Dr. W. Hodgson Ellis, of Toronto, and other analysts, with a view of ascertaining to what extent the English standards are applicable here. -Yours, etc., Ottawa, February 27th, 1888. [Mr. Shute's report is too long for insertion a t present, in extenso, but the following are the figures PRANK T. SHUTE, M.A., F.C.S., Chemist, Dominion Experimental Farms. of the analyses referred to.-ED. ANALYST.] GRAINS PER GALLON. A B C D Coloiir in 2-ft. tube . . . . . . . . . Dark Yellow Smell at 100" F. . . . . . . . . . Slightly peaty Chlorine . . . . . . . . . . . . . . . -035 -035 -03 5 ,035 Phosphoric acid . . . . . . . . . None Nitrogen in nitrates and nitrites ... -0080 *0103 -0126 9109 Free ammonia.. . . . . . . . . . . *0014 -0014 -0007 -0007 Rlbuminoid ammonia . . . . . . . . *0091 *0084 *0084 -0084 Oxygen absorbed in 15 minutes . _ . -1912 *16 10 -1708 -1629 Solids ... . . . . . . . . . 3-80 3-70 3.92 3.92 Oxygen absorbed in 4 hours . . . . . . -3511) -3507 -8507 -3507 Hardness as Ca60 . . . . . . . . . 1.64 1.40 1.55 1 -55

ISSN:0003-2654    

DOI:10.1039/AN8881300080

出版商:RSC    

年代:1888

数据来源: RSC