摘要:

THE CHARACTERISTICS OF SOME ALMOND AND ALLIED OILS. BY DR. J. LEWKOWITSCH, F.I.C. (Bead at the Meeting, Dacember 2, 1903.) A HITHERTO unsolved problem in fat analysis ip; the detection of apricot and peach kernel oils in almond oil. The ordinary quantitative reactions applied in fat analysis are of hardly any use here. It is well known that most of the commercial L g almond oil ” is apricot kernel oil, and in the trade an oil described as ‘‘ oil of sweet almonds, French ” (oleum amyg- dalarum gallicum), is nothing 0lse but apricot kernel oil or peach kernel oil. Genuine almond oil is sold under the name of ‘‘ almond oil, English.” Through the kindness of Mr. Brewis and Ur. W. C,. Allen, T have been placed in possession of several samples crf almond oils, apricot kernel oils, and peach kernel oils of undoubted genuineness (Nos.2 to 9 in the following table). It may perhaps be useful to collate the numbers which ere usually ascertained in the examination of fats.106 THE ANALYST. I have added the values obtained for a genuine sample prepared for me some ten years ago by a German firm from pure Valencia almonds. Description of Oil. Almond oils, expressed from : 1. Valencia sweets 2. Blanched Valencia sweets 3. Sicily sweets 4. Mazagan bitters 5. Small Indian almonds 6. Mogador bitters 7. Peach ker- nel oil 8. Apricot kernel oil 9. Apricot kernel oil from Mogador kernels 10. Californian apricot kernel oil 0.91995 0.9182 0.91i8 0.9180 0.91907 0-9183 0.9198 0.9200 0.9172 0.92026 8 $ 6 .r( a2 d 3 gs - 207'6 191.7 183.3 188.6 189'2 194.98 191.4 192.4 198.2 190 -3 0)' .2 s zz 99.4 103.6 L00*3 102 '5 96-65 104.2 95.24 107'4 .07*9 .08*7 ad -a E +g 5-16 2.9 0.79 3 -1 2.9 1.3 3.0 2 -3 2-8 1 -2 FATTY ACIDS.207% 196.4 198.8 196.8 195.8 197'1 196'8 198'0 194.0 197.8 $ 2 5 G &F: $3 G P 207.6 201.7 202'2 203 -1 200'7 203.2 205.0 202.0 200 -7 202% Colour Tests. Bieber's Test. Colourless Colourless Colourless Colourless Colourless Colourless Colourless a t first, then pink tion Pink colora- Slightly pink Very slightly pink Phloroglucinol Test. No coloration No crimson coloration No crimson coloration Slightly crimson Slightly cnmson No crimson coloration Deep crimson coloration Deep crimson coloration Less deep crimson than 8 Less deep crimson than 8 Mr. Ross, to whom my best thanks are due, was kind enough to determine the refractive indices of the ten oils for different rays.Unfortunately, the numbers given below do not furnish an andytical means of differentiating almond oil from the related oils. REFRACTIVE INDICES AT 20" CENTIGRADE. D. 0. F. G. No. 1. 1.4715 ... 1.4688 ... 1.4780 ... 1.4835 No. 2. No; 3. No. 4. No. 5. No. 6. No. 7. No. 8. NO. 9. No. 10. 1.4715 1-4711 1.4712 1.4710 1.4714 1.4710 1.4717 1.4715 1.4725 ... 1.4688 ... 1.4685 ... 1.4686 ... 1-4685 ... 1-4688 ... 1.4685 ... 1.4692 ... 1.4690 ... 1.4700 ... ... ... ... ... ... ... .a. ... 1.4780 14777 1.4778 1.4777 1.4780 1.4776 1 *4784 1.4782 1.4792 ... 1-4836 ... 1.4833 ... 1.4834 ... 1-4833 ... 1.4835 ... 1.4832 ... 1.4839 ... 1.4837 ... 1.4847THE ANALYST. 107 I t will be seen that no information of a discriminative nature can be gained from the figures contained in the foregoing tables.Recourse must therefore be had to colour reactions. Much in vogue, and in fact the only one that gives some indications, is Bieber’s test. This consists in treating 5 measures of the oil with 1 measure of a mixture consisting of equal parts (by weight) of sulphuric acid, fuming nitric acid, and water. Pure almond oil does not change colour, whereas peach kernel oil assumes a peach-blossom tint. I t is best to prepare Bieber’s reagent afresh for each set of tests. I t should also be noted that the colour reaction is much stronger in the case of fresh oil than with a sample which has been kept for half a year or longer. Mixtures of almond oil and apricot kernel oil containing one-third of the latter are coloured distinctly, but mixtures containing 25 per cent. of apricot oil only slightly, so that it would be certainly somewhat hazardous to pronounce adulteration on the strength of this colour test.Peach kernel oil gives the same colour reaction, but in a much fainter degree, and only after standing for some time. I t will be more risky still to judge from this test as to adulteration of a given sample of almond oil. Maben’s statements as to the differences in the elaidin tests are unfounded. Although with concentrated sulphuric acid apricot and peach kernel oils give darker colorations than almond oil, this test is perfectly useless. The same criticism holds good with regard to Maben’s zinc chloride test. per cent.ether solution i n the presence of nitric acid, specific gravity 1.45, has been proposed as a test for apricot kernel and peach kernel oils. Undoubtedly, apricot kernel oil and peach kernel oil give a distinct deep crimson coloration with the reagent, in contradistinction to some almond oils ; yet some specimens of the above-described genuine almond oils show more or less strongly the same reaction. This test must therefore be employed with the utmost care. Unfortunately, the quantities at my disposal did not permit me to examine the fatty acids, especially the liquid fatty acids, as thoroughly as I could have wished, since it may be hoped that differences between almond oils and the other oils can be established in the yield of the tetrabromides, the differences in the iodine numbers of the oils becoming much more pronounced in the liquid fatty acids than in the mixed fatty acids.I have added in the last two columns of the table the neutralization and saponi- fication numbers of the fatty acids. These were ascertained, together with those of many other fatty acids, in view of Tortellz’s and Peygami’s statement that nearly all fatty acids contain small quantities of lactonic substances. These numbers will be published elsewhere, and I must content myself with stating that the experimental numbers did not wholly bear out the statements of those chemists; in fact, in some cases the difference between the saponification and neutralization number was a negative one, the difference exceeding the experimental values. The numbers given for the first almond oil bring out the same fact.Dieterich states that by Crismer’s method of determining the critical temperature Recently, phloroglucind* in * Chwolles, l ’ h a r ~ Zeit., 1903, p. 109.108 THE ANALYST. of dissolution differences between almond and the allied oils are observed. not yet been able to verify this experimentally, I have DISCUSSION, The PRESIDENT (Mr. Fairley) having invited discussion, Mr. E. T. BREWIS said that in 1890 Mr. W. C . Allen and he had examined a series of oils from known sources [Pharm. Journ. (IV.), vol. xi., p. 871 similar to those with which they had been able to provide Dr. Lewkowitsch, and their conclu- sions from the figures then obtained had been that the specific gravity and saponifica- tion value were not of very much assistance.It seemed possible, however, that the iodine value might afford some means of differentiating between almond oil and apricot kernel oil. The iodine values obtained were somewhat lower than those given by Dr. Lewkoaitsch, but, speaking generally, the iodine value of genuine almond oil was lower than that of apricot kernel oil, while the iodine value of peach kernel oil WGS intermediate, but pretty close to that of almond oil. With regard to celour reactions, Bieber’s test and the nitric acid test (which latter was official in the British, German, and American Pharmacopoeias) gave with apricot kernel oil a deep salmon-red coloration, almond oil a white or whitish mixture, and although some specimens varied somewhat, any coloration produced with a genuine almond oil was but slight, and, quite distinct from the reaction of other oils, with the exception of peach kernel oil, which gave an intermediate result.This fact had been pointed out some years previousIy by Mr. J. C. Umney, and he (Mr. Brewis) was able to confirm it, and h9 believed that Dr. Lewkowitsch had also obtained a similar result. There was, considerable misapprehension as to the peach kernel oil occurring in commerce, which he believed was originally due to an erroneous idea as to the source of the kernels used. At the ti&e that what is now sold as peach or (and) apricot kernel oil was introduced into English commerce, the kernels were known on the market under the general name of (‘ peach kernels,” whence the term (( oIeum amygdala persica ”- viz., the oil from t c the peach ” (Amygdalus persica), and not, as some incorrectly translate it, ‘( Persian almond oil.” At the present time, however, the kernels from which 01.amygd. persic. dulc. is expressed are mainly apricot kernels, of which a much larger quantity is imported than of peach kernels. The kernels themselves could now be distinguished by the difference in their appearance, the peach kernel being flat while the apricot kernel was quite plump. Apricot kernels coming from different parts of the world, such as Persian or Syrian kernels, and those from America, differed somewhat in appearance, and the oils from them also gave slightly different figures; but on the whole the iodine value of almond oil was lower than that of apricot kernel oil and peach kernel oil came in between.He could quite corroborate Dr. Lewkowitsch’s experience as to the unreliability of colour tests generally. Bieber’s test, however, is useful for distinguishing apricot-kernel oil from the others, if nothing else. With reference to the nitric acid test, the Pharmacopoeia, after stating that in the case of almond oil no colour should be given with the mixture of water and nitric acid, went on to say that, on standing for six hours at 10” C., a deposit should, in the caseTHE ANALYST. 109 of almond oil, appear in the tube. He did not find that with all genuine almond oils, and he would like to see some further work done on this point, for he thought that in that respect both the British and the German Pharmacopaeias were hardly correct.Mr. ALLEN inquired whether Dr. Lewkowitsch insisted on the strength of the nitric acid being 1.45, because that was a somewhat awkward strength to obtain. Acid of specific gravity 1.42 distilled unchanged, while 1.50 to 1.52 was what was termed fuming nitric acid. Both of these were commonly readily available, but 1-43 acid was an intermediate strength which would usually have to be specially prepared. He gathered from Dr. Lewkowitsch's demonstration that it did not much matter how much of the phloroglucinol solution or how much of the nitric acid was used. He quite agreed with Mr. Brewis as to the misapprehensions which existed in commerce with regard to these oils, and which often caused much difficulty in dealing with such cases.Probably it would be best if almond oil were defined as the fixed oil from almonds, peach kernels or apricot kernels, for probably all three were equally useful. He was afraid that the tests laid down in the British Pharmacopda for distinguishing between almond oil and peach kernel oil or apricot kernel oil were not to be regarded as trustworthy. He would like to see described as genuine any oil derived from the same botanical family and having the same therapeutic value and the same physical characters, though probably further research might lead to the establishment of a correct method for differentiating between these very closely allied oils. Dr. SCHIDROWITZ inquired whether any particular difference had been found to exist between ordinary expressed almond oils and oils extracted by ether.The point, perhaps, was not one of any importance commercially, but from an analytical point of view it sometimes might be. He had recently had to examine two samples of ground almonds to ascertain if they were adulterated, and, having extracted some of the oil, had obtained therefrom results which corresponded fairly well with those now given by Dr. Lewkowitsch. With some of the colour tests the samples had certainly given different results. In one case the Bieber test gave a faint reaction, and in the other none. The same applied to the zinc chloride test and the nitric acid test. The only important difference, however, between the two samples, beyond a decided difference in taste, was in the acidity of the almonds themselves.One of the samples, on direct titration, showed an acidity equivalent to 1-06 per cent. of oleic acid, and the other an acidity equivalent to 0.77 per cent. But after standing for a few days, the acidity in the first case had increased to 3.4 per cent., and in the other case to 1-23 per cent. Curiously enough, in the case of the sample with the higher acidity the saponification and iodine values of the extracted oil were less satis- factory than in the other sample. Dr. LEWKOWITSCH said the point he had wished to raise was not so much the differentiation of almond oil from apricot kernel oil-which, taking all tests together, would seem to be not very difficult-but the detection of admixtures of, say, 20 per cent. or 30 per cent. of these oils to almond oil, a question which was sometimes put before the analyst, and which was very difficult to decide.As to the strength of nitric acid to be used, he did not lay down any fixed strength. So long as one did not know what was the chromogenic substance which caused the colour reaction, as in the case of sesame oil, such tests were really more or less valueless. In the110 THE ANALYST. present case the suitability of acid of 1-45 strength wa8 more or less of the nature of Q compromise; 1.5 acid caused the ether to boil and spoiled the test, whereas in 1.4 acid there was insufficient nitrous acid ; hence a few, drops more or less might be required in different cases. He was afraid that, in the matter referred to by Dr. Schidrowitz, chemistry would not be able to afford much assistance. Microscopical examination and taste would give more information in such a case than any chemical test. It would be quite intelligible that the more bitter sample should have a greater acidity, and hence should become more Rtrongly rancid, very likely in consequence of hydrolysis set up by a ferment. Dr. VOELCKER inquired whether there was any marked difference in commercial value between almond oil and peach kernel or apricot kernel oil, or any difference in properties which made an admixture undesirable. Dr. LEWKOWITSCH said that he personally could not see that any great harm would be done to a buyer by supplying him with apricot kernel oil or peach kernel oil instead of almond oil, but, of course, almond oil was the dearer oil. Mr. BREWIS said that the wholesale price of peach kernel oil was from 7d. to 9d. per pound, while thst of almond oil was from 1s. 4d. to Is. 8d. Apart from the question of price, a sharp commercial distinction was .drawn between almond oil and peach kernel (and) or apricot kernel oil, and very little peach kernel oil as such occurred in the market at all.

ISSN:0003-2654    

DOI:10.1039/AN904290105b

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

110 THE ANALYST. NOTE ON CHINESE TALLOW-SEED OIL. BY L. MYDDELTON NASH, F.I.C. (Read at the Meeting, February 3, 1904.) CHINESE tallow-seed oil is obtained from the seeds of Sapium sebiferum (syn. Stdlingia sebifera), a tree of the natural order Euphorbiacea This tree, which is indigenous to China and the adjacent islands, is known as the “tallow-tree.” It has been found to grow well in North India, and has also been introduced into South Carolina. Its leaves are about 2 inches broad, rhomboid-shaped, sharply tapering, and pointed ; they are attached to slender stalks, and have two prominent glands situated at the point of attachment between the stalk and leaf; its flower catkins are from 2 to 4 inches long. The fruit is about 8 inch in diameter, and contains three seeds thickly coated with a fatty substance, which yields the tallow.The hard wood of the tree is used by the Chinese for printing-blocks, and its leaves yield a black dye-stuff. The vegetable tallow, known to the natives as c c pi-yu,” is commonly extracted by the following method : The kernels, after being carefully removed from the hard outer shells, are placed in a large wooden drum provided with a number of holes. A current of steam is passed through the drum, when the melted tallow runs out into a receptacle placed beneath it. After the tallow has solidified it is again melted, filtered, and cut into cakes weighing about 1 hundredweight each, in which form i t is exported to Europe.THE ANALYST. 111 6 b Tee-ieou” or (‘ ting-yu” is the name given to the oil extracted by expression from the kernels left after the operation just described, and is 8 liquid oil with drying properties.I t is used as an illuminant and in the manufacture of varnish. pi-yu ” and (‘ ting-yu,” obtained from the whole seeds by a combination of the above process. mou-idou ” and b b pi-yu ” are sold under the name of Chinese vegetable-tallow, but the former is not so hard or white as the latter. The sample of tallow-seed oil which I examined is of a brown colonr, and has an odour resembling that of wood oil. Its viscosity, measured at 15.5” C., is about three-fifths that of rape oil. When cooled to 0” C. no stearine is deposited. A film of the oil on glass becomes nearly dry in three days and quite hard in The following results were obtained from the examination of the sample : The yield of oil is about 59.5 per cont.“ Mou-iQou ” is a mixture of Both six days ; it must therefore be classed among the drying oils. ... ... ... Specific gravity at 15.5’ C. 15-5’ C. Free fatty acids (as oleic) ... ... ... Unsaponifiable matter ... ... ... ... Saponification equivalent ... ... ... Iodine absorption (Hubl) ... ... ... Iodine absorption of fatty acids ... ... Hehner number ... ... ... ... ... Ineoluble fatty acids ... ... ... ... Combining weight of fatty acids ... ... Rotatory power (in 100-millimetre tube) about ul, Zeiss-butyro figure at 20’ C. ... ... ... Refractive index Y,, at 20” C. ... ... ... ... 0.9395 ... 3.1 per cent. ... 0.44 ,, ... 277 ... 160.7 ... 165 ... 94.4 ... 272 ... - 4 O ... 89.1 ...1.4835 ... 93-96 per cent. The fatty acids on cooling and standing separate into a solid and a liquid portion. The oil gives no very distinctive colour reaction with sulphuric acid. One drop of the concentrated acid on 20 drops of the oil gives a red-brown coloration, changing, on stirring, to a muddy-brown, and finally to ;L very dark brown. I n conclusion, I have to express my indebtedness to Professor Dunstan, F.R.S., director of the Imperial Institute, for kindly supplying me with the information aa to the botanical origin and method of producing the oil contained in this paper. DISCUSSION. Dr. LEWKOWITSCH said that the earliest paper on the subject of this oil was one published some years ago by Tortelli and Ruggeri, who named the oil (‘ Stillingia oil,” a name he had adopted in his “Laboratory Companion.” Those observers had recorded the laevo-rotatory property of the oil, and he was glad to find this confirmed now by Mr.Nash, because it was one of the most important characteristics of the oil. sample of the mixed fatty acids of the oil, which showed an iodine value of 181.8, a considerably higher figure than that given by Mr. Nash. The liquid fatty acids, freed from the solid portion, had the iodine value 191.1. These figures indicated Mr. Nash had been kind enough to afford him the opportunity of examining112 THE ANALYST. that the oil was one of high drying power, and, therefore, one which might very well be substituted for linseed oil when the latter should become dearer. The high iodine value, he had found, could not be due to any error, since he had it confirmed by what he ventured to call the (' hexabromide test "-ie., the amount of hexabromides obtain- able on treatment of the liquid fatty acids with bromine.The Stillingia oil acids yielded 25.78 per cent. of hexabromide, a proportion which was hitherto regarded as a maximum for linseed oil, though he (Dr. Lewkowitsch) had found the latter to yield as much as 40 per cent. The divergent results hitherto recorded for Chinese vegetable tallow were probably to be accounted for by the practice of selling not only the solid tallow and the liquid oil separately, but also a mixture of the two ; so that a, sample described as a vegetable tallow from China might be either the solid tallow or any product intermediate between it and the oil.In view of this, it might be interesting to mention that in the case of the solid tallow the iodine value was about 20. The figures of 50 or thereabouts whioh were on record probably referred to mixtures of the solid tallow and the oil. Mr. HERBERT E. BURGESS suggested that, since optical activity was very unusual in fatty oils, it might be worth while to steam-distil the oil and examine the fractions with a view to ascertaining to what the la3vo-rotatory power might be due. It was to be noted that the oil had a distinct scent. The PRESIDENT inquired whether the refraction figures given were obtained with the simple form of instrument specially designed for butter examination, or with the more complete instrument that could be used for a greater variety of work. Mr. NASH, in reply, said that possibly the difference in the iodine numbers might be due to the use by Dr. Lewkowitsch of Wijs's process, whereas he (Mr. Nash) had used the old-fashioned Hu bl process. Steam distillation would probably afford in- teresting results, but that the quantity of the oil at present at his disposal was too limited for the purpose. The refractometers (which had been kindly lent to him by Mr. Burgess) mere (1) a form of the Abbe refractometer, very similar to the ordinary Zeise butyro-refractometer, its readings, however, being in terms of the actual refrac- tive index, and (2) the Zeiss butyro-refractometer itself.

ISSN:0003-2654    

DOI:10.1039/AN9042900110

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

112 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. M. Popp. (Zeit. fiir Untersuch. der Nahr. und Genussmittel, 1904, vii. , 6-12.)-The author has carried out a series of investigations on the reliability of this method (ANALYST, 1898, xxiii., 259), and especially on the influence of variations in the strength of the ammonia used, on the time required for separation of the ether layer to take place, and on the determination of fat in cream by this process, He finds that solutions of ammonia, containing from 4.80 to 24.99 per cent. of NE, may be employed without appreciable The Gottlieb-Rose Method for determining Fat in Milk.THE ANALYST. 113 influence on the results. The ether layer was found to separate completely in one hour. For the purpose of estimating fat in cream, 3 to 5 grammes of the latter are weighed into the cylinder, diluted with water to 10 c.c., and treated:with ammonia, alcohol, and ether, etc., as in the case of milk.After standing one hour the ethereal layer is drawn off as completely as possible ; the solution remaining in the cylinder is once more shaken out with the ether-petroleum spirit mixture, allowed to stand thirty minutes, and the ethereal solution again drawn off. The united extracts are then treated as usual. w. P. 8. The Use of Amy1 Alcohol i n Gterb3r’s Method for determining Fat in Milk. M. Siegfeld. (Zeit. fur. mzgew. Chem., 1903, xvi., 1217-1220.)-The author confirms Van Haarst’s statement (ANALYST, 1903, 213) that some samples of apparently pure amyl alcohol give considerably too high results when used in Gerber’s process.A traction was obtained from a sample of amyl alcohol, which, when used in the above process, yielded 3.9 per cent. of With regard to the nature of this insoluble substance, an ultimate analysis gave results agreeing with formula for amyl alcohol, but the boiling-point was too high for any of the known isomers of the latter. Whether the substance is present in the original amyl alcohol or is formed by the action of the sulphuric acid is still undecided. The best test as to the suitability of any particular sample of amyl alcohol for use in this process is a blank experiment with the same. fat.” w. P. s. On the Use of Phenolphthalin for the Detection of Heated Milk. Utz. (Milch Zeit., 1903, xxxii., 722 ; through Chm.h i t . Rep., xxvii., 328.)zAccording to the author, a mixture of an alkaline solution of phenolphthalin and dilute hydrogen peroxide cannot be used for the detection of boiled milk, as neither boiled nor .unboiled milk gives a colour with the reagent in the cold, whilst the colour produced by warming to 30” or 40’ C. is permanent in-both cases. A. G. L. The Estimation of Methyl Alcohol in Presence of Ethyl Alcohol. T. E. Thorpe and J. Holmes. (Proc. Chem. SOC., xix., 285.)-The method depends on the diflerence in action of a mixture of potassium dichromate and sulphuric acid a n methyl and ethyl alcohols, the evolved carbon dioxide being weighed. The method is applicable to the examination of methylated spirits and medicinal preparations.A. G. L. The Interdependence of the Physical and Chemical Criteria in the Analysis of Butter-fat. T. E. Thorpe. (Journ. Cliem. SOC., 1904, lxxxv., 248-256.)-1n the course of an investigation on the chemical nature of butter produced within the British Isles, which was instituted by the Board of Agriculture for the information of the Departmental Committee on Butter Regulations (this vol., p. 67), a number of butters of known origin, and produced from milk given under varying climatic con-114 THE ANALYST. ditions, were analysed. Of 430 samples received, 357 were examined as regards their Reichert-Wollny number, their specific gravity, saponification equivalent, refractometric number, and, in a certain number of cases, their Hubl-iodine value. A summary of the results obtained is given in the following table : __.~ Number of Samples. 7 17 15 27 37 51 78 56 41 18 10 357 -_ Reichert- Number. Woll11y 22-5 23-5 24.5 25.5 26-5 27.5 28-8 29-5 30.5 31.3 32.6 -_ - ~- Specific Gravity a t 37 *go c. 3- 0.9101 0.9104 0.9108 0.9110 0.9113 0.9114 0.9118 0.9120 0.9123 0-9125 0.9130 -- -- __ ____ 3aponificatior Equivalent. -- 255.4 253.4 251.3 251.1 248.9 247.4 245.7 244-0 242.4 241-5 241.2 , Refracto- Soluble meter Acids." Kumber Per Cent. a t 45" c. 42.0 41.5 41.5 41.3 41-0 40.6 40.1 40.1 on Fat. 4.3 4.5 4.7 4.8 4.9 5.2 5.4 5.6 39.9 , 5.8 39.7 ' 5.7 39.4 6.0 1 I i Insduble Acids. Per Cent. on Fat. 90.1 89.7 89.4 89.3 88.9 88.7 884 88.3 87.9 87.9 87.7 -~ _ _ - Meail Molecular U'eight of Insoluble Acids. 266.9 265.5 265.0 264.2 261-9 261.7 260.9 259.6 260.1 258.0 257.8 -- Twenty samples, with an average Reichert-Wollny number of 24.2, had a mean iodine value of 40.0, whilst thirty other samples, having an average Reichert-Wollny number of 30-8, gave a mean iodine value of 32.4.The interdependence of the main values obtained are shown in a series of curves, and full details of the origin of the samples are published in the Minutes of the Evidence to the Report of the Com- mittee (Cd. 1750, Appendix xxix., 505-588). w. P. s. Determination of Alcohol in Tinctures. T. F. Xarvey. (Chemist and Drzbggist, 1904, xliv., 178.)-The method described consists in diluting the tincture, distilling, and treating the distillate with kieselguhr or kaolin to remove undiwolved oil. The dilution in no case need exceed three times the original volume.To prevent the diluted tincture frothing and bumping during the distillation, a, little paraffin and a few pieces of ignited pipe-clay are added. The kieselguhr or kaolin must be previously washed and dried. If there be any doubt whether a tincture has been sufficiently diluted, further dilution of the distillate will settle the point. About 0.5 gramme of kieselguhr is usually sufficient, and the specific gravity of the treated distillate after filtration is determined. w. P. s. Determinhtion of Starch by Baumert and Bode's Method. H. Witte. (Zeit. fur Untersuch. der Nuhr. und GenussmitteE, 1904, vii., 65-77.) - This method (ANALYST, 1901, xxvi., 20) has been found to give good results with potato starch, * Calculated as bntyric acid.TRE ANALYST.115 'but with wheat-meal and maize flour the figures obtained were always too low. By slightly altering the method, principally as regards time of digestion and final washing of the precipitated starch, the author obtains reliable results with these two flours. I n the case of wheat-flour, the digestion is allowed to proceed for two hours at a pressure of 4 atmospheres. After precipitating with alcohol, as previously described, the residue is washed on to the asbestos filter with a mixture of 25 C.C. of alcohol and 15 C.C. of water, and then successively with mixtures consisting of 25 C.C. alcohol and 15 C.C. water ; 25 C.C. alcohol, 10 C.C. water, and 5 C.C. hydrochloric acid (10 per cent.) ; 25 C.C. alcohol and 15 C.C.water ; then with alcohol, and finally with ether. Maize and rice starches must be digested at a pressure of 4.5 atmospheres. I n the analysis of flours it is pointed out that as the different proteids in flours contain from 16.90 to 18.39 per cent. of nitrogen, an approximation only of the amount of total proteids is obtained by multiplying the nitrogen by a factor. The author, however, found that by using a factor of 6.25, and determining the starch by difference, the percentage of starch agreed closely with that obtained by the above method. As regards the consistently low results given by Dennstedt and Voigtlander's colorimetric method for the determination of starch (ANALYST, 1895, xx., 210), the errors are most likely due to the presence of substances intermediate between starch and dextrin, which substances are insoluble in cold water, and give no blue colour with iodine.w. P. s. The precipitate is dried, weighed and ignited. Characteristics of Olive Oil in which Sardines have been preserved. M. Henseval and M. Deny. (Chenz. Rev. Fett-u. Hum-Ind., 1904, xi., 44-46.)-Sardines were preserved in boxes in the usual manner by sterilization at 110" C . , and the following values show the changes produced by the diffusion of the fish oil into the olive oil, for a year : Specific gravity ... ... Maumend test . . . ... ..- Refractometer reading at 25" C. Acid value ... ... ... Hehner value ... ... ... Reichert value.. . ... ... Iodine value . . . ... ... Unsaponifiable matter, per cent, Saponification value . . . ... Acetyl value .. . ... .-- Glycerin, per cent. ... ... Melting point . . . ... ... Solidification point . . . ... Acid value . . . ... ... Saponification value . . . Iodine value ... ... ... Acetyl value* ... ... ... Fatty Acids. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... Original Olive Oil. 47.3 62.6 5.7 194.9 95.8 0.86 84.9 7.1 10.5 0.95 0-91736 26.7" C. 21.2" c. 200.0 210-57 87-68 10.75 Sardine Oil. 0.9274 96.5 76.5 194.5 6.88 95.10 1 -40 142.0 8.8 10.48 1-36 25-4O c. 27.9' c. 196.3 200.8 147.5 8-4 Olive Oil from the Tin. 0.9186 59.9 65.4 6.8 195.2 94.67 2.00 97-2 7 -08 10.70 0.79 27-08' C. 22.55" C. 201.12 212.24 99-42 10.50 C. A. M. * Lewkowitsch's method.116 THE ANALYST. Cocoanut Oil in Lard. Mecke. (Zeit. f i i r oflentZ. Chem., 1904, x., 8, 9.)-A lard, having an unusually soft consistency, gave on analysis an iodine number of 54.6 and a refractometer number of -2.6.With Halphen’s test a feeble brown coloration was obtained. By shaking the melted lard with alcohol, cooling, filtering, and evaporating the latter, a residue was obtained having an iodine numbar of 39.5, a saponification number of 235, and a refractometer number of - 6-7. From these results the author considers that cocoanut oil wag present in the lard. W. P. S. Detection of Artificial Colouring in Dried Peas. K. Lendrich. (Zed. fiir Untersuch. der Nukr. and Genussnzittel, 1904, vii., 1-5.)-1t is not unusual for dried peas, either in the whole or split condition, to be artificially coloured. The dyed peas are generally treated with talc to give them a polished appearance.The colours employed are greens or orange-yellows, and may be detected by shaking the peas with a mixture of equal parts of alcohol and water and decanting the latter after the lapse of five minutes. With natural peas the solution is colourless or only slightly tinged, whilst with dyed peas an orange-yellow or deep green extract is obtained. The alcoholic solution may then be further teeted as usual by dyeing wool, etc. Talc when present is readily removed from the peas by shaking the peas with water. On decanting the latter and allowing it to stand for a time, the talc settles and may be recognised under the microscope. By treating the ash of the peas with dilute hydro- chloric acid, the talc remains insoluble and may be quantitatively determined.w. .P. s. Searle’s Test for Yeast Extract, H. E. Davies. (Pharm. Jozim., 1904, lxxii., 86, 87.)-The author finds the precipitate formed by boiling yeast extract with the modified Fehling’s solution, previously described in a paper by Searle (Analyst, 1903, 360), may contain considerable quantities of copper oxide, and that even the modified solution itself, on boiling for three minutes, gives a precipitate of copper oxide. He has also, in some cases, obtained precipitates with pure meat extracts. Xearle (ibid.) points out that although meat extracts do sometimes give small precipitates with this test, the appearance of the precipitate is totally different from that yielded by yeast extract. The test is essentially a qualitative one, and depends on the physical characteristics of the precipitate, and not on the weight of the latter.The mixture should not be boiled for more than one minute. With longer boiling copper oxide is thrown down. Although some yeast extracts fail to give quantitative results, others yield approximately constant weights of precipitate. w. P. s. The Determination of the Quantity of Eggs in Pastry. H. Luhrig. (Zeit, f6T Untersuch. der Nahr. und Geimssmittel, 1904, vii., 141-151.)-The most trust- worthy results are obtained by determining the phosphoric acid combined as lecithin and also the ether extract yielded by the sample. The pastry is extracted with ether for twelve hours and then with hot alcohol for a similar time. The phosphoric acid in both extracts is determined in theTHE ANALYST.117 usual way, the sum of the two giving the lecithin-phosphoric acid.” Wheatmeal without eggs gives an average of 0.0229 per cent. of (‘ lecithin-phosphoric acid ” and 1-06 per cent. of ether extract, whilst eggs give an average of 0.320 per cent. and 9-49 per cent. respectively (See also ANALYST, Vol. xxv., p. 100.) w. P. s. Examination of Commercial Peppers. J. W. Gladhill. (Anzer. Journ. Pharna., 1904, lxxvi., 71-81.)-The author has examined typical samples of thirteen different kinds of pepper. In the determination of the piperine 10 grammes of the ground pepper were thoroughly extracted with 95 per cent. alcohol, the extract evaporwted, and the residue mixed with about 100 C.C. of a 10 per cent. solution of potassium hydroxide, and allowed to stand for twenty-four hours with occasional agitation, so as to bring the resins into solution.The undissolved substance was collected on a filter, dissolved in 95 per cent. alcohol, the solution filtered and evaporated, and the crystals weighed as piperine. The oleo-resin was determined by deducting the piperine from the amount of ethereal extract. The following results were obtained : Peppers. Blac k. Singapore (4) . . . ... Tellicherry (4) . . . ... Aleppy (2) ... ... ... Trang (2) ... ... ... . V . , Lienburg (4) . . . ... Lampong (4) . . . ... W.C. Sumatra (2) ... ... Acheen, A (4) ... . I . ,, c (a) ... ... Coriander (4) . . . ... Singapore (3) , . . ... Penang (3) . . . 1 . . ... Decorticated (3) . . . ... White, I Ash. _I Per Cent.3.5 to 4-5 3.8 ,, 4.8 4.7 ,, 4.7 3.8 ,, 3.9 3.6 ,, 4.0 5.0 ,, 5-5 4.0 ,) 4.3 4.0 ,, 4.7 0.8 ,, 1.0 1.0 ,, 1.2 2.1 ,, 2.8 0.8 I , 1.9 Hulls. Eight samples . . . ... ~ 7.0 ,, 9.6 Ethereal Extract. Per Cent. 8.76 to 9.76 7.26 ,, 8-85 9.47 ,, 9.65 8.44 ,, 8.83 8.70 ,, 9.48 8.76 ,, 10.31 9.22 ,, 9.28 9.20 ,, 10.10 7.90 ,, 11-68 8.20 ,, 8.78 6.80 ,, 7.20 6.60 ,, 7.64 5-00 ,, 8.93 Piperine. Per Cent. 6-58 to 7.68 5-91 ,, 6.82 6.75 ,) 7.70 5.12 ,, 5-61 5.98 ,, 6.50 7.00 ,, 8.30 6.68 ,, 7.00 7.10 ,, 7-96 6.81 ,, 9-00 6.78 ,, 7-26 5.74 ,, 6.76 6.25 ,, 7.02 None Oleo-resin. Per Cent. 1.08 to 2.63 0.70 ,, 2.83 1.95 ,, 2.72 3.22 ,, 3.39 2.20 ,, 3.22 1.16 ,, 2.30 2.28 ,, 2.54 2.10 ,, 2.50 1.06 ,, 2.68 1.00 ,, 1.67 0-44 ,, 1.30 0.24 ,, 1.39 5.00 ,, 8.93 The author concludes that the ash should not exceed 6.5 per cent.in the case of black pepper, or 3.0 per cent. for white pepper. He makes a constant allowance of 1 per cent. for sand and other accidental material. Black pepper should yield between 7.5 and 10 per cent. of ethereal extract, and white pepper between 6 and 9 per cent. Only itl the case of coriander pepper did it exceed 9 per cent., but this variety is never ground for white pepper on account of its cost. The piperine should range from 5.5 to 9 per cent, in good black pepper, and the author takes the former118 THE ANALYST. figure as a minimum standard. only adulterants used to any considerable extent. He states that at the present time the hulls are the C. A. M. The Determinat.ion of Citric Acid by Means of Lime. 0.v. Spindler. (Chem. Zeit., xxvii., 1263.)-The author has investigated Klinger and Bujard's method (Zeits. angew. Chem., 1891, 514), in which the citric acid is weighed as calcium citrate, Ca, (C,H,(OH)(COO),), + 4H,O, and shows that the method is utterly unreliable, as the salt is very appreciably soluble in water, even in the presence of ammonium chloride. He also shows that the salt slowly loses water even at 100" C., and that it contains more than the theoretical amount of calcium if it has been obtained by the direct neutralization of citric acid with lime. A. G. L. A New Modification of Denighs' Reaction : The Detection of Tartaric Acid in Citric Acid. 0. v. Spindler. (Chem. h i t . , xxviii., 15.)-The author modifies Denigds' test for citric acid by using a 0.5 per cent.solution of potassium bichromate instead of the 2 per cent. potassium permanganate solution. The test is carried out by dissolving 0.5 gramme of the acid to be examined in 10 C.C. of water, adding 2 C.C. of mercuric sulphate solution (obtained by dissolving 5 grammes mercuric oxide in.20 C.C. sulphuric acid and 80 C.C. water), heating to boiling, and adding 2 C.C. of the bichromate solution. The liquid is then allowed to stand. Citric acid alone produces only a yellow precipitate containing chromium and mercury; tartaric acid, on the other hand, reduces the bichromate with production of the usual green colour. With 5 per cent. of tartaric acid the reaction is quite sharp, the colour beginning to change at the end of five minutes. A. G. L. A Suggested Test for Free Salicylic Acid in Bismuth Salicylate.W. Lyon. (Pharm. J o z ~ ~ n . , 1904, lxxii., 219.)-The official test for this impurity being unreliable, since the alcohol exerts a decomposing action upon the bismuth salicylate, a reaction being obtained with ferric chloride similar to that indicating the presence of free salicylic acid, though none was present in the sample, the author suggests the sub- stitution of benzene for. the alcohol. A small quantity of the salt is placed on a filter, benzene is poured on it, and the filtrate collected on the surface of a dilute solution of ferric chloride contained in a test-tube. Should free salicylic, acid be present, a violet ring appears at the junction of the two liquids. w. P. s. Colour Reactions of Pilocarpine. E.Barral. (Joztm. Pharm. Chim., 1904, xix., 188, 189.)-The most characteristic reaction of pilocarpine is the violet colora- tion (colouring matter soluble in benzene) obtained on adding a few drops of potassium bichromate solution, followed by a, few drops of hydrogen peroxide solution, to the pilocarpine solution. Sodium persubhate heated with 1 or 2 C.C. of a dilute solution of pilocarpine gives a yellow coloration, and emits vapours with a slightlyTHE ANALYST. 119 ammoniacal odour. These vapours turn turmeric paper blue, and blacken mercurous nitrate. Szdphuric acid with formalin, when heated with a few drops of a, pilo- carpine solution, gives a yellow coloration changing to yellowish-brown, then to blood red, and finally to brownish-red. Mandelin’s reagent, heated with a very dilute solution of pilocarpine, gives a golden yellow coloration gradually changing to bright green, and finally to bright blue. Potassium permangunate in a 1 per cent.solution in strong sulphuric acid, when heated with a solution of pilocarpine, is at first decolorized, and then becomes dark yellow, and gives off vapours with an odour exactly like that of tartaric acid decomposed by heat. C. A. M. New Reactions of Acetanilide. E. Barral. (Joum Pharm. Chim., 1904, xix., 237.)-The phosphomolybdic reagent for phosphates added to a solution of acetanilide gives a bright yellow precipitate. This is soluble on heating, and can thus be distinguished from the similar precipitate given by phenacetin. M a d e l i d s reagent added to a solution of acetanilide gives a red coloration changing rapidly to brownish- green, whereas with phenacetin an olive-green coloration is obtained, changing to reddish-brown on heating. C. A. M. New Colour Reactions of Phenacetin. E. Barral. (Journ. Pharm. Chim., 1904, xix., 237, 238.)-In addition to the reactions mentioned above (preceding abstract) the following are described : Sodizm perszclphate heated with a solution of phenscetin gives a yellow coloration, becoming orange after prolonged boiling. Bromine water heated with a few crystals of phenacetin turns them rose-coloured, whilst the liquid itself becomes orange-yellow. On cooling, a brown precipitate is gradually deposited. Millon’s reagent heated with phenacetin gives a yellow colora- tion changing to red. Nitrous ether is then liberated and a yellow precipitate formed. C. A. M.

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THE ANALYST. 119 TOXICOLOGICAL ANALYSIS. A Ptomaine Resembling Veratrine in some Respects. Stiiber. (Zeit. fur Untersuch. der Nahr. und Geizussmittel., 1903, vi., 1137, 1138.)-As is wen known, rats play an important part in the dissemination of plague. In the course of an examination of the bodies of 114 dead rats, found in the hold of a vessel arriving at Hamburg from a suspected port, the author obtained a ptomaine" from the bodies which, in certain of its chemical reactions, resembled the alkaloid veratrine. A bacteriological examination of the bodies gave a negative result as regards the bacteria of plague, and no metallic poisons were present. The purified substance consisted of a yellowish, amorphous mass. When treated with concentrabed sulphuric acid it gave a yellow coloration, changing to orange and finally to violet. A trace of the substance with concentrated hydrochloric acid yielded a bright cherry-red coloration, exactly similar to that obtained with veratrine. The characteristic blue colour given by the latter when treated with a mixture of sugar and sulphuric acid was not * For a similar rase, see Otto. A.u.nuittelzcnq der G f t e , 1896, 115.120 THE ANALYST. yielded by this ptomaine. Iodine and tannin solutions gave precipitates, but platinic chloride and mercuric chloride did not react with the substance. It also differed from veratrine by producing no muscular contractions when injected into a frog. The cargo of the vessel consisted of cotton-seed, wood, also maize which had become putrid. w. P. s.

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DOI:10.1039/AN9042900119

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年代:1904

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120 THE ANALYST. ORGANIC ANALYSIS. Determination of Spirits of Turpentine in Alcohol Denatured with this Substance (0'5 per cent.). (Oester. Chem, Zeit., vi, 562.)- The method is based on the determination of the bromine value of the mixture, the bromine used being only liberated during the titration; 50 C.C. of the alcohol to be examined are mixed with 25 C.C. water, 10 C.C. dilute (1 : 3) sulphuric acid, and 10 C.C. dimethylorange solution (0.02 gramme per 1 litre) ; a solution containing 50 grammes potassium bromide and 15 grammes potassium bromate per 1 litre of water is then added drop by drop from a burette until the pink colour of the liquid disappears. The 50 C.C. of alcohol containing 0.5 per cent. turpentine should require 11.7 to 12.4 C.C. of the bromine solution, corresponding with an absorption of 1-87 to 1.98 grammes bromine per 1 C.C.turpentine. Umberto Chierego. A. G. L. A Method of Determining Aldehydes. S. S. Ssdtler. (Amer. tJozwn. Phamt., 1904, lxxvi., 84-88.)-This is based upon the fact that on adding a, neutral sulphite solution to an aromatic or fatty aldehyde an addition-compound is formed, whilst sodium hydroxide is split off, and can be determined by titration with standard hydrochloric acid. C,E,,COH + 2H,O + 2Na2S0, = C9H17COH(NaHS0J2 + 2NaOH. I n applying the method to oil of lemon, from 5 to 10 grammes are exactly neutralized with $ potassium hydroxide solution with rosolic acid as indicator, and then treated with 25 to 50 C.C. of a 20 per cent. solution of sodium sulphite, previously neutralized with hydrochloric acid after being heated by immersion in a water-bath.The red colour formed in the aqueous layer is discharged from time to time by the addition of hydrochloric acid, the flask being heated and frequently agitated. If the two layers be kept well mixed, the reaction is complete in about thirty minutes, and the amount of acid required can then be calculated into citral in accordance with the above equation. Duplicate determinations of the citral in a sample of lemon oil by this method gave (1) 5.24 and (2) 5.29 per cent. The accuracy of the method has been proved by the analysis of mixtures containing known quantities of citral, and by results obtained with crystalline vanillin. In the case of the latter the reaction was complete in the cold. The reaction was also capable of detecting 1 part of formaldehyde in 1,000,000 parts of milk, etc., of detecting acetone in wood spirits, and of determining acetaldehyde in grain spirits.It is generally applicable to any essential oil where the main aldehydic constituent is known. Thus in the case of citral the reaction agrees with the formula : (Cf., Burgess, ANALYST, xxix., 78.) C. A. M.THE ANALYST. 121 The Detection of Acetone in Urine. Vournasos. (Bzd?. SOC. Chaiu., 1904, xxxi., 137-139.)-A solution of iodine in methylamine is more sensitive than other reagents used for the detection of acetone. It acts upon acetone in the same manner as on lactic acid, yielding (in the presence of alkali) iodoform, which combines with the nitrogen of the amine forming an isonitrile (methylcarbylamine), which is readily recognised by its characteristic odour.The reaction is capable of detecting 1 part of acetone in 100,000. In applying the test, 10 C.C. of the urine are rendered alkaline by the addition of 1 C.C. of a 10 per cent. solution of sodium hydroxide, and filtered. The filtrate is then treated with 1 C.C. of the freshly-prepared reagent containing 1 part of sublimed iodine, 0.5 part of potassium iodide, and 5 parts of methylamine in 50 parts of water. After the addition of the reagent, the urine is heated to the boiling-point, and when acetone is present, the odour of the isonitrile is soon perceptible. Alcohol and chloroform also give the reaction, and so in the case of pathological urines containing those substances it is necessary to fractionally distil a larger amount of the alkaline urine, and to test the distillate.A solution of 5 parts of iodine in 50 parts of aniline (boiling point 183.7" C.) can replace the methylamine solution as the reagent, and is stated to be equally sensitive. C. A. M. South American Orange Oil. J. C. Umney and C. T. Bennett. (Pharm. Joz~rrz., 1904, lxxii., 217, 218.)--,4 sample of this oil shipped from Buenos Ayres had a specific gravity of 0.887, and optical rotation +2O. I t contained 36.5 per cent. of esters (reckoned as linalyl acetate) and 38.4 per cent. of alcohols (reckoned as geraniol). The total alcohols amounted to 67.1 per cent. The oil resembled the ordinary Paraguay variety of petit-grain oil, but had a more delicate odour, and contained a higher percentage of free alcohols. I t contained no methyl anthranilate, the most characteristic constituent of neroli oil.Fractional distillation under reduced pressure and further fractionation and examination of the distillates showed that the oil con- tained terpenes, pinene, dipentene, geranyl acetate, and other estere, linslol, geraniol and t erpineol. w. P. 8. Some Rare Fixed Oils. (3. R, Pancoast and W. Graham. (Amer. Journ. Pharm., 1904, lxxvi., 70, 71.)-The following values have been obtained in the examination of some less-known fatty oils : OILS. Walnut. ::':- *k:i:y- Lobelia. Stroph- Pumpkin. Larkspur. vzga. Eriot. anthns. at 15" C. ... 0.925 0.917 0.921 0.925 0-927 0.920 0.881 0.935 0.918 Specific gravity Acid value ... 3.5 3.5 2.3 - Saponifioation - - - - 3.5 value ...197.0 1925 195.6 - - 195.5 - - - C. A. M.122 THE ANALYST. Chinese Tallow. Mecke. ( Z e d . frir ijflentl. Chciii., 1904, x., 9.)-.4 tallow is now imported into Europe from China which, as regards its soft consistency and brownish colour, resembles Australian tallow. A sample of this fat gave the following figures : Iodine number . . . . . . ... . . . ... 44 to 46 Refractive index at 60" C. ... . . . . . . 1.4503 Welman's reaction ... . . , ... faint green Furfural reaction . . . . . . . . . ... intense red Soltsien's (zinc-chloride) reaction ... .. negative . . . Bechi's reaction ... . . . . . . ... negative That the fat was not mixed with sesame oil is shown by the negative result with Soltsien's reagent. After repeated washing with 'glacial acetic acid the fat gave no furfural reaction.Baudouin's reagent yielded scarcely any coloration with the fat. This indicates that the assumption that Baudouin's reaction depends upon the formation of furfural by the action of hydrochloric acid on sugar is open to doubt. By evaporating the acetic acid extract of the fat, saponifying the residue, and extracting the soap with benzine, a residue is obtained on evaporating the latter which gives a reaction with furfural. The fatty acids separated from the extracted soap yield no reaction. The soap similarly obtained from sesame oil gives a strong reaction, but the benzine extract does not. w. P. s. Colophony. W. Fahrion. (Zeits. f. ajigew. Chew, 1904, viii., 23'3-241.)-The author claims to have proved that the principal constituent of American colophony is an acid of the formula C.10H3002, which may consist of several isomers.I t eaeily becomes oxidized, and then yields products insoluble in petroleum spirit. Mach and others have put forward the formula C1!,H?OOP, but although the results of organic. analyees agree better with this latter, it is suggested that the percentage of carbon and hydrogen may have been diminished by some oxidation which had taken place. The author brings forward the results of determinations of the acid values of the acid in corroboration of his formula. -4. Rl. A Method of Grading Soape as to their Detergent Power. H. W. Hillyer. (Journ. dmer. Clrem. SOC., xxv., 1256.) -The method used depends on the fact previously found by the author (Joirrn.Attier. Chem SOC., xxv., 511, 524), that when a soap solution is made to form drops beneath the surface of an oil, the number of drops formed from a given volume of the solution is dependent on the amount of soap in the solution, and on the emulsifying power of the soap, and, further, that the emulsifying power of a soap may be taken as a measure of its detergent properties. The apparatus used consists of a pipette, A , which holde 5 C.C. from a mark on its upper stern to another on the lower capillary outlet tube, the bore of which is 0.5 millimetre, and which ends in a smooth horizontal surface 10 millimetres in diameter, from which the drops fall. The stem has a bore of 3 millimetree, and ie widened at its upper end into a small funnel. The oil receptaole, BC, coneisteTHE ANALYST.123 practically of two test-tubes connected by an overflow tube, 60 that the oil in B can overflow into C, and, consequently, be maintained at the same level in B. In using the apparatus, 2 or 3 C.C. water are poured into B, followed by 20 C.C. of kerosene. Some of the soap solution to be tested is heated in a boiling water-bath, poured into the pipette, and expelled through the capillary by blowing at the other end. After repeat- ing this twice, the pipette is filled, supported in a cork, dipped into the kerosene, and the number of drops formed from the 5 C.C. is counted. The test may be carried out either at room temperature or at 100" C., according to the use8 to which the soap is to be put, by placing the oil receptacle in a beaker of cold or hot water respectively.As a standard for the hot test, a solution is used containing 1 gramme sodium palmitate in 200 C.C. watei. This is prepared by adding 0.921 gramme palmitic acid to 36 C.C. >zr sodium hydroxide solution, and diluting to 200 C.C. with water. Of this solution, 10 c.c., 20 c.c., 30 c.c., and 40 C.C. respectively, are diluted to 50 C.C. with boiling water. The number of drops formed by 5 C.C. of each of these solutions, as well as by the undiluted standard, is then ascertained, the results being plotted in 8 curve. For the cold test a similar curve is plotted, using a solution of 1 e;l.amme sodium oleate in 200 C.C. water as the standard, and diluting this in the same way. To value a soap by means of the hot test, 0.5 C.C.of the sample is disaolved in 100 C.C. hot water, and the number of drops formed by 5 C.C. at 100" C. counted; the result in terms of sodium palmitate is then read off on the curve. For the cold test, 0.5 gramme of fine shavings are allowed to stand overnight with 100 C.C. cold recently-boiled water ; the solution obtained is stirred and filtered through a dry covered funnel, letting all that will pass through the filter run through iL The filtrate is then stirred gently and 5 C.C. tested as above, and compared with the sodium oleate standard. From the results obtained, the author believes the test to give good comparative results. Duplicate results by the hot test ure said to vary by less than 1 per cent., taking the sodium palmitate as 100, and those by the cold test by about 4 or 5 per cent.A. G. L. On the Determination of Sulphur in Glue. Otto Krummacher. ( h z t . Bioi., 1903, xlv., 310 ; through Chewb. h i t . h i p . , xxviii., 5.)-On burning glue by .means of compressed oxygen in a Mahler bomb the author found that in the case of purified glue 17 per cent. of the total sulphur remained in the ash, whilst in the case of commercial samples 27 to 30 per cent. of the sulphur were fixed. A. G. L.124 THE ANALYST. Investigations on the Accurate Determination of Sulphur in Vegetable Substances and other Organic Bodies. ( J o z m . Landzo., 1903, xxvi., 289 ; through Chem Xeit. Rep., xxvii., 327.)-The substance to be examined is weighed out into one or more boats placed in a hard glass tube, 70 centimetres long and 1.5 centimetres in diameter, drawn out at one end.At a distance of about 30 centimetres from the drawn-out end a hard glass tube 6 or 7 millimetres in diameter is fused into the larger tube. Between the side tube and the drawn-out end a layer of ‘‘ soda-quartz ” (v.2.) is placed, which is kept in place at one end by a perforated platinum disc, and at the other end, nearest the substance, by a fairly long spiral of platinum wire, The substance itself is placed on the other side of the side-tube. The ‘‘ soda-quartz ” is made by mixing pieces of rock-crystal, about 1 or 2 millimetres in diameter, with 3 to 4 grammea sodium carbonate and a little water, and drying the mass over a spirit-lamp. As soon as the tube has been charged, a current of carbon dioxide is led through the wide tube from a narrow tube going through a cork in the end nearest the substance, the side tube being closed by means of a piece of rubber and a clip; at the same time, the ‘6sodaquartz” is heated to a dull red at the end nearest the substance, the other end being only very geotly heated.As soon as vapours are visible in the wide tube, a current of oxygen is led in through the side-tube, which serves to burn them, the sulphuric acid produced being absorbed by the sodium carbonate. When no more vapours are given off the current of carbon dioxide is stopped, and oxygen led in at this end also until the carbon in the boat is completely burnt. When combus- tion is complete, the boat containing the ash and the soda-quartz ” with its platinum supports, are removed separately; the tube is rinsed out with water, the washings being added to the “soda-quartz,” which is next treated with hydrochloric acid, evaporated to dryness, and baked, after which the sulphuric acid it contains, derived from the volatile sulphur, is determined as usual. The sulphur in the ash is also determined. This method is said to give higher and more concordant results than eight others investigated by the author. W. E. Barlow and B. Tollens. The substance itself is then heated gradually. The whole operation takes about twenty to thirty minutes. A. G. L. The Determination of Nitrogen by the Kjeldahl Method. - Robert Banks Gibson. (Joimz. ilwzr. C h e s ~ . SOC., xxvi., 105.)-The author ascribes the bad results obtained by Kutscher and Stendel (Zeits. physiol. Chem., xxxix., 12) with the Kjeldahl method to an insufficient time of heating. Using the Gunning modification, with potassium sulphate, he himself obtained practically theoretical results with a, number of substances such as uric acid, hippurio acid, tyrosine, thiourea, caseinogen, etc. (cf. ANALYST, this vol. p. 53). A. G. L.

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THE ANALYST. 125 INORGANIC ANALYSIS. The Volumetric Determination of Zinc. W. Ueorge Waring. (Journ. Amer. Chem. SOC., xxvi., 4.)-The auther cites a number of errors likely to affect the ferro- cyanide method for zinc as ordinarily carried out. The most important of these are due to volatilization of zinc chloride at as low a temperature as 145" C. when heated with ammonium chloride and hydrochloric acid ; to the recombination of zinc with silica in ammoniacal solution when ammonia is added to the solution of a siliceous ore to precipitate iron and aluminium; to the insolubility in acids of zinc aluminates, which are perfectly decomposed only by fusion with potassium bisulphate ; to the use of too much hydrochloric acid in the final solution ; and to the employment of an incorrect standard for the ferrocyanide solution, The following method is said to give excellent results for even the most complex zinc ores; for simpler compounds some of the operations may of course be omitted or modified.The method depends on the separation of zinc from manganese, iron, and aluminium by means of hydrogen sulphide, under slight pressure, in a solution very slightly acidified with formic acid, the metals of the copper group having been previously separated by metallic iron or aluminium. For most ores, solution can be effected by treatment with hydrochloric acid or aqua regia, the nitric acid in the latter case being destroyed by evaporation with an excess of hydrochloric or sulphuric acid. If zinc spinels or aluminates are present, the insoluble residue is decomposed by fusion with sodium carbonate and borax, or, if no silica, is present, with potassium bisulphate, any lead sulphate having previously been dissolved out by ammonium acetate.The solution of the melt is added to the main solution. Some silicates, such as furnace cinders and slags, may be at once fused with sodium carbonate before treating them with acid. I n all cases the silica may be filtered off in the gelatinous state, thus saving the evaporation to dryness. I n the filtrate the metals of the copper group, except lead and cadmium, are next precipitated by boiling for fifteen minutes with a strip of clean iron or steel. Metallic aluminium may also be used for this reduction, and has the advantage of precipitating cadmium and lead as well as the other metals.When copper and aluminium are to be determined on the same portion, sodium sulphite or thiosulphate may also be used for the reduction. In any case, the liquid is filtered into a 300 C.C. flask, made slightly alkaline with caustic soda, using methyl orange as indicator, then just acid with 50 per cent. formic acid solution, after which another 0.5 C.C. formic acid is added, and the liquid diluted so as to contain not more than 0.15 to 0.20 gramme metallic zinc per 100 c.c., and heated to 80" C. Hydrogen sulphide is then led through the solution; as soon as zinc commences to come down, the flask is closed with- out interrupting the current of the gas, so as to saturate the solution with hydrogen sulphide under the pressure of the generating apparatus.The resulting precipitate settles easily, and can be washed with hot water. It is dissolved in 10 C.C. concen- trated hydrochloric acid, the filter-paper being washed with hot water until the total volume is about 125 C.C. If iron was used for the original precipitation, any cadmium present will be left undissolved at this stage; an equal volume of hydrogen sulphide water is added to the liquid, the cadmium sulphide filtered off, and determined with126 THE ANALYST acid ferric sulphate and perqnganate as usual.. The einc chloride solution is heated to 60" C., made up to 200 or 250 C.C. with hot water, a little ammonium chloride is added, and the zinc is titrated with ferrocyanide solution, made by dissolving 21.63 grammes potassium ferrocyanide m d 7 grammes sodium sulphite in 1 litre of water free from air.As a standard a solution of 6.23 grammes zinc oxide in 60 C.C. acetic acid made up to 1 litre with water is used. The amount of ferrocyanide solution required to give a colour with the uranium acetate solution when no zinc is present must always be deducted from the burette reading. If only small amounts of zinc are present, the author recommends igniting the sulphide precipitate obtained as above to oxide, and weighing instead of titrating. Or else, in the solution of the ore, the zinc is determined as phosphate after removing iron, aluminium, calcium, magnesium, and any heavy metals present as usual. A. G. L. Quantitative Reduction by Means of Aluminium. N. Tarugi. (Cfazz. chim. ital., xxxiii., vol.ii., 223 ; through Chem. Zeit. Rep., xxviii., 4.)-Aluminium reduces silver completely in two to three hours from a solution of its nitrate acidulated with sulphuric acid ; under similar conditions copper is only incompletely reduced. A. G. L. Experiments on the Electrolytic Separation of the Metals of the Alkaline Earth Group. Alfred Coehn and Wilhelm Kettenbeil. (Zeits. .dnorg. Chem., xxxviii., 198.)-From the authors' experiments it appears that, using a mercury cathode, it is possible to separate, at least approximately, the metals of the alkaline earth group from each other by taking advantage of the fact that the current potentials necessary to separate them from solutions of their chlorides differ by several tenths of a volt. The method will, however, require further working out before it can lay claim to be quantitative, A.G. L. Determination of Alkalies in the Presence of Borstee. K. Jacobi. (Journ. dmer. Cheiu. Soc., xxvi., 88.)-Two grammes of the substance are dissolved in hydrochloric acid ; silica, iron, aluminium, and calcium are removed as usual, and magnesium is precipitated by ammonium phosphate. The excess of phosphoric acid is then removed by dding ferric chloride. The filtrate is evaporated to dryness twice with nitric acid to remove ammonium salts, the residue being evaporated twice with hydrochloric acid to remove nitric acid. The residue finally obtained is dissolved in water, the solution filterad into a weighed platinum dish, evaporated to dryness, and the residue ignited, at first very gently, and finally for ten minutes at a red heat, after which it is weighed.I t consists of anhydroue boric oxide, B,O,, sodium chloride, and sodium borate, Na,B,O,, due to the interaction of boric wid and sodium chloride at a high temperature. The residue in the dish is then dissolved in hot water, the sodium oxide present as borate is determined by titrating with sulphuric aoid, using methyl orange a8 indicator, and then the total boric acid by addingTHE ANALYST. 127 glycerin and titrating with potassium hydroxide, using phenolphthalein. The quantity of sodium chloride present is then obtained by subtracting from the total weight of residue the sum of sodium and boric oxides found. Should potassium or sulphuric acid also be present, they must be determined in separate portions, and their presence in the residue allowed for.The method appears to give good results. A. G. L. A New Method for the Determination of Free Lime, and on so-called " Dead-Burnt '' Lime. Edward H. Keiser and S. W. Forder. (,dmer. Chew&. Joum., xxxi., 153.)-The method described for the determination of free lime in Portland cement and similar substances depends on the fact that free lime combines almost instantly with water, whereas basic calcium silicates are acted upon much more slowly. It is carried out by first heating 0.2 to 0.5 grrtmme of the substance to be examined in a platinum crucible over the blast-lamp for a few minutes to remove water and carbon dioxide, weighing, and then adding a few drops of distilled water free from carbon dioxide.The crucible is next placed in a cylindrical brass box, D (see figure), fitted with a screw-top carrying a brass inlet and outlet tube, the screw- F h A-KOOR Bulb B--CaCl,TUbO C-Thermometer D-Brass Protector E-Porcelain dish for cmcfhle F-Platinum crucible G '-copperair- joint being made tight with white-lead and oil. The whole is put into an air-bath, G, and heated to 85" C. for thirty minutes. A slow current of purified air is then drawn through the apparatus for thirty minutes, the iiemperature being raised at the same time to 185" C . to expel the excess of water, after which the crucibls is placed in a desiccator containing caustic potash, and allowed to cool. From the increase in weight the quantity of free lime present is calculated. Results obtained in this way on pure lime vary from 99.26 to 101.00 per cent.of CaO. To ascertain the behaviour of so-called " dead-burnt " lime, pure lime was fused by means of the electric arc, and treated as above. At a temperature of 85' C. slaking was found to be complete at the end of two hours. The method was next tried on the compounds usually assumed to be present in Portland cement. For this128 THE ANALYST. Compound. (CaO)SiO, . . . ... 2(CaO) SiO, . . . purpose mixtures of pure lime and silica or alumina were fused by means of an OXY- coal-gas blowpipe and treated as above, the following results being obtained : Hydraulic Properties. None. Not quite as hard as cement. I 0.42 0.30 0.52 1.01 1.33 0.93 1-61 3-15 ... ~~(cGI)s~o, ... 1 1: 3( CaO) SiO, ... Hard as cement.4( CaO) SiO, ... None. Y, 9, $ 9 1, 2(Ca0)A1,03 . . . 3(CaO)A1,0, . . . Like a cement.. None. I of 1 Percentage of Lime Water taken UB. calculated from Water. Percentage Composition of Cement. 5A12O3, 25Sio2, 70Ca0 ... 9A1,O3, 21Si02, 70CaO ... 15Al2o3, 15SiO,, 70Ca0 ... Percentage of Set slowly; did not become quite as 1.43 Set slowly, and became quite as hard 2.16 Set slowly, and became very hard. ~ 4.65 Hydraulic Properties. Water taken up. -- hard as Portland cement. as Portland cement. 3 molecules of lime to 1 of sil& take up water only with great diflculty ; aluminates, on the other hand, are readily decomposed, and behave like free lime. Three synthetic cements were next prepared from pure lime, silica, and alumina, and tested by the same method, with the following results : I I ~ It appears that, as the percentage of alumina present increases, the percentage of water taken up increases ; but if the quantity of alumina does not exceed 10 per cent.-as is the rule in commercial cements-then the amount of water taken up does not exceed 3 per cent These conclusions were confirmed on testing a number of '' sound " commercial cements, the quantity of water taken up varying from 1-81 to 3.04 per cent.One sample of commercial cement examined took up 10.17 per cent. of water, indicating the presence of 7 per cent. of free lime ; a pat made from the neat cement proved to be altogether unsound. Finally, the method was tested by adding 15.40 per oent. of lime to a cement which took up 1.16 per cent. of water, corresponding to the presence of 3.60 per cent.of free lime. After adding the lime, the cement took up 6.25 per cent. of water, corresponding to 19-44 per cent. of free lime instead of 19.00 per cent. A. G. L.THE ANALYST. 129 On the Determination of Small Quantities of Sodium Hydroxide and Car- bonate in Soap. p. Heermann. (Chem. Zeit., xxviii., 53 and 60.)-The author condemns the older methods as being inexact, and quotes results obtained in favour of the following method for determining the cawtic soda : From 5 to 10 grammes of the soap are dissolved in 250 C.C. recently boiled distilled water; 10 to 15 C.C. of neutral concentrated barium chloride solution are added to precipitate the carbonate and fatty acids, and the solution is warmed until the barium soap collects into one mass.The liquid is then filtered or, preferably, decanted from the soap, which is washed, the solution being then titrated with & acid, using phenolphthalein as indicator. To determine the carbonate, the soap is either salted out with sodium chloride from its aqueous solution, which is then titrated for total free alkali with methyl orange and acid; or else the finely-divided soap is dried, dissolved in absolute alcohol, and carbon dioxide passed through the solution to preuipitate the total free alkali as carbonate, which is washed with hot alcohol, dissolved in water, and titrated as before, In either case, the sodium hydrate found accordiug to the first method must of course be subtracted from the NaOH plus Na,CO, obtained. The author prefers this last method. A.G. L. The Determination of Thiocyanates in the Presence of Salts precipitated by Silver, (Ann. de Chim. anal., 1904, ix., 45-46.)-The electrolysed solution of a pure chloride furnishes a neutral oxidizing agent that rapidly converts thiocyanates into sulphates without affecting cyanides. Suitable solutions for the purpose, containing 18 to 20 grammes of chlorine per litre, are readily obtained by cooling the anode during the electrolysis of sodium chloride or magnesium chloride. In the determination the solution of the thiocyanate, the strength of which should be sufficient to yield 0.2 to 0.4 gramme of barium sulphate, is mixed with a solution of 2 gramrues of barium chloride in 50 C.C. of water, and 50 C.C. of the oxidizing agent added little by little with constant stirring.After ten minutes the liquid is acidified with 10 C.C. of pure hydrochloric acid and heated to the boiling-point, and the beaker left for an hour on the water-bath for the barium sulphate to settle. The supernatant liquid is then decanted, and the precipitate washed two or three times with boiling water, collected, and weighed. The method, however, can also be used for the determination of sulphides. The author states that he has obtained closely concordant results in the determination of thiocyanic acid in the residual liquors from the manufacture of ferrocyanides. A. Dubosc. C. A. M. On the Determination of Silica in Silicate Mixtures. Ed. Donath. (Oester. Chem. Zeit., vi., 561.)-Confirming the results obtained by Lunge and Milberg (Zeit.ungew. Chem., 1897, 393), the author finds that when complex silicates are treated with hot 10 per cent. sodium carbonate solution, not only silica, but alumina and, occasionally, ferric oxide pass into the solution. The amount of alumina, dissolved may reach 1 per cent. and upwards. A. G. L.130 THE ANALYST. On the Quantitative Determination of Fluorine in Fluorides. A Critical Study of the Wohler-Freeenius Method. Karl Daniel. (Zeits. Auorg. Chem., xxxviii., 257.)-As the result of a long and elaborate investigation, the author comes to the conclusion that the Wihler-Fresenius method for fluorine gives accurate results, provided that a number of precautions are used, chief amongst which appears to be the destruction of all organic matter accidentally present, by heating the sulphuric acid to be used for the determination to its boiling-point in the apparatus itself before introducing the fluoride.For other details the original article rnust be consulted. A. G. L. On the Reduction of Alkali Iodates and Chlorates with Hydrazine Sulphate. Max Schlotter. ( Z e d s . Anory. Chem., xxxviii., 184.)-The author shows that potassium iodate is completely and instantaneously reduced to iodide if its hydrochloric acid solution is allowed to flow gradually into an excess of a solution of hydrazine sulphate. If the hydrazine sulphate solution is added to the iodate solution, on the other hand, iodine is set free, the reduction not being so complete. Chlorates are also converted quantitatively into chlorides by hydrazine sulphate, but the reaction is much slower, requiring several hours’ heating for its completion.A. G. L. A New Chlorometric Method. J. Pontius. ((‘hem. Zeit., xxviii., 59.)-This method for the determination of available chlorine in bleaching-powder depends on the oxidation of iodides to iodates by means of hypochlorous acid, and the liberation of iodine from iodides by means of iodates. For a determination, 7.1 grammes of the bleaching-powder are treated with water, the whole is made up to 1 litre, and 50 C.C. are measured out into a beaker containing 3 gramrnes solid sodium bicarbonate, which reacts with the calcium salts with formation of calcium carbonate, sodium chloride, and hypochlorous acid. After stirring well, 1 or 2 C.C. of starch solution are added, and the liquid is immediately titrated with ->G potassium iodide solution (containing 2.7667 grammes::: potassium iodide per litre), until the blue colour produced is permanent.3CaOC1, + GNaHCO, + KI = KIO, + 3CaC0, + 6NaC1+ 3C0, + 3H,O. If other bleaching agents, such as e m d e Javelle, are examined by this method, any free alkali they may contain must first be neutralized ; this is best done by adding an excess of boric acid, which is without influence on the above reaction. The potassium iodide solution used should be standardized against arsenious acid and a sample of bleaching-powder. From the test analyses given the method appears to give very good results, and it is also much more rapid than the original one of Penot. A. G. L. The reactions which take place may be expressed by the equation : - __ On Eschka’s Method for Sulphur Determinations.Otto Pfeiffer. (Chesn. Zeit., xxviii., 38.)--A Bunsen burner is used to heah the crucible containing the One-sixth of a niolecnle of l i I being relliiired for one atom of Cl.THE ANALYST. 131 mixture of coal and Eschka's reagent. To prevent contamination by the sulphur in the gas, the crucible is placed in one hole cut in the 'top of an inverted tray of sheet- iron, which is placed on the top of a tripod. To a second hole a chimney is fitted, which draws the burnt gases away from the crucible. The latter is made to fit tightly on the eheet-iron by means of an asbestos ring cemented to the iron by means of sodium silicate. The author uses a porcelain crucible in place of the more usual platinum one, and also uses this method for determining sulphur in indiarubber.A. G. L. The Iodometric Determination of Phoaphorus. E. Rupp. (Arch. Phccrm., 1903, ccxli., 321-326 ; through Zeit. fiir Untersiuh. cler Ndtr. u?ul Gewssmittel, 1904, vii., 158.)-Yellow phosphorus is quantitatively oxidized by :G iodine solution within twenty-four hours, if about 5 C.C. of carbon disulphide be added to the mixture. About 5 grammes of sodium-potassium tartrate are also added to neutralize the hydriodic acid formed. In titrating the excess of iodine solution, the thiosulphate solution should be added slowly with constant agitation. I t is unnecessary to add starch solution, as the characteristic colour of the iodine diasolved in the carbon disulphide serves as an indicator.On0 C.C. of & iodine solution is equivalent to 0*00062 gramme of phosphorus. ,4ny araenic in the latter is counted as phosphorus, but if necessary the areenic may be separately determined by Gooch and Morris's method, in which the arsenic acid is reduced by hydriodic acid, and the arsenious acid produced titrated with iodine solution in the presence of sodium hydrogen carbon ate. w. P. s. The reaotion is shown by the equation : P, + 51, + 8H,O = 2H3P0, + 10HT. A New Method for the Detection and Determination of Phosphorus in Oils. W. Straub. (.4rcli. Pharm., 1903, ccxli., 335-340 ; through Zeit. j'iir liittersuch. dele Nnhr. mid Geiz~~ss~)~ittel, 1904, vii., 158.)-By shaking 10 C.C. of a 0.1 per cent. solution of phosphorus in oliveoil with 25 C.C.of a 1 per cent. copper sulphate solution a brown- black emulsion is obtained. On continuing the agitation for from four to five hours, the brown coloration disappears, and when allowed to stand, the mixture separates into two layers, the whole of the phosphorus being found in the aqueous layer as phos- phoric acid, together with the copper sulphate. After removing the aqueous portion, the phosphoric acid in it is determined as usual. The disappearance of the brown colour indicates that the oxidation of the phosphorus is complete. w. P. s. On the Determination of Citric- Acid-Soluble Phosphoric Acid in Thomas- Slag. (Ckent. Zeit., xxvii., 1125.)-The author proposes the following rapid method for the examination of Thomas-slag comparatively poor in silica (cf.ANALYST, xxviii., 50, 159): The citric acid extract is prepared as usual; 100 C.C. are placed in a 200 C.C. flask, 75 C.C. of ammoniacal citrate solution are added, the whole is boiled up rapidly and allowed to stand five or ten minutes; if no 0. Bottcher.132 THE ANALYST. precipitate soluble in hydrochloric acid appears, the solution does not contain a injurious amount of silica, and the phosphoric acid may be determined in 50 C.C. as usual. On the other hand, if a precipitate of silica is obtained, the liquid is made faintly acid with hydrochloric acid, made up to the mark, and filtered through ti large filter-paper, 100 C.C. of the filtrate being then precipitated with 25 C.C. of magnesia mixture. A. G. L. Contributions to Technical Chemical Analysis.G. Lunge. (Zeits. f: aiigew. C h m . , 1904, vii., viii., ix., 195-203, 225-236, 265-270.)-Indicators.-Methyl orange and phenolphthalein are again recommended (see ANALYST, 1903, 307). Objections are raised to the use of para- and ortho-nitro-phenols on the ground that they are distinctly affected by carbonic acid and that the end-points are not sharp. Jferric salicylate, recommended by J. Wolff for the titration of boric acid, Lunge finda to be in no way preferable to methyl orange, the results given being identical. Stmulard Substances for Alknlimtric Titmtwns.--Potassium biniodate does not require the theoretical quantity of acid for neutralization when methyl orange is used as indicator, because iodic is but a weak acid. With phenolphthalein in a boiling solution the results agree with the theoretical, but are not very sharp.Potassium tetroxalate cannot be readily obtained with the correct proportion of water of crystallization; all the samples prepared according to the directions of 0. Kiihling or J. Wagner contained too much water. Sodium oxalate, prepared after the method of Sorensen, gives accurate and reliable results (see ANALYST, 1903, 306) ; so also does sodium carbonate, if made by gently igniting the bicarbonate. Iot7ometry.-Potassium biniodate and tetroxalate are rejebted, because, as is stated, it is difficult to obtain them in a state of sufficient purity. The method suggested by Kalman of standardizing iodine solution by adding an excess of sodium sulphite and titrating the acid set free is rendered unsatisfactory from the fact that it is difficult to obtain sulphite free from carbonate; the titration is consequently troublesome.The author, therefore, prefers to standardize thiosulphate solution against pure iodine, freshly weighed. Permnngaiiate Solutio)i.-This solution may be titrated with hydrogen peroxide, the strength of which has been determined by measuring the volume of oxygen evolved on shaking with permanganate solution and sulphuric acid. A. &I. Technical Analysis of Water. H. R. Procter. (Joitrii. SOC. Chem Ind., 1904, i., 8-lO.)-The determination of the hardness in water is of importance in many industries, but has hitherto been considered too exclusively from the point of view of the soap user. The soap test may with advantage be replaced by others of a more scientific and reliable character.The ‘‘ temporary hardness,” which is due to bicarbonates, is best estimated by Hehner’s method. The water is titrated with decinormal hydrochloric acid in the cold, using a minimum quantity of methyl orange as indicator. A blank determination should be made with distilled water titrated until the same tint is observed. The end reaction is, however, sharper if alizarinTHE ANALYST. 133 he used as indicator, the titration being conducted at 100” C. This indicator is prepared by mixing 1 gramme of pure alizarin paste with 200 C.C. of water. The colour-change is from violet in alkaline solution to clear pale lemon-yellow in neutral or acid. As this indicator is affected by carbonic acid, it is necessary to conduct, the whole of the titration at the boiling-point, and to use a vessel of either silver, platinum, or porcelain. The ‘‘ permanent hardness,” which is due to various salts, such as magnesium sulphate, should be determined by Pfeifer and Wartha’s modification of Hehner’s method (Zeits.fi angezi!. c‘hem., 1902, 198), in which a fairly large excess of a mixture of decinormal solutions of sodium carbonate and hydroxide are added to 200 C.C. of the water. The liquid is then reduced in volume to 200 c.c., or even less by boiling in a platinum dish or a flask of Jena glass ; it is then cooled, made up to 200 c.c., allowed to settle, 100 C.C. syyhoned off, and titrated with decinormal acid, The difference between this titre and that of the alkali originally added gives the amount of magnesium sulphate or other similar salt present in 100 C.C.of the water. The same water may be used for this operation which was neutralized with acid in the estimation of the temporary hardness; in this case, however, the titration will give the ‘‘ total hardness.” In some cases the permanent hardness as determined by these methods appears to be negative; this is due to the presence of sodium carbonate in the waters in question. Since, in the ordinary methods of water softening, lime is precipitated as carbonate, and magnesia as hydroxide, double the quantity of caustic alkali or lime being consumed, it is desirable to know the amount of magnesia present. This may be ascertained by rendering the water neutral and precipitating with lime-water, which throws down the magnesium, but does not affect the calcium salts.Pfeifer neutralizes 100 C.C. of the boiling water, using alizarin as indicator, as in the determination of the temporary hardness, which determination may be combined with that of the magnesia. A known quantity of clear lime-water (25 or 50 c.c.), which should be at least 50 per cent. in excess of that required for precipitating the magnesia, is added, the whole mixed and allowed to settle, and an aliquot portion of t h e clear liquid taken and titrated with decinormal acid either in the cold, using phenolphthalein, or a t boiling-point, using alizarin as indicator. The diminution from the original titre of the lime-water gives the quantity of magnesia in the water. Free carbonic acid (i.e., CO, not combined as bicarbonate) may be estimated by Archbutt’s method” of titrating with sodium carbonate solution and using phenolphthalein as indicator. A. 11 The Defects of Uncarburetted Water-Gas as Fuel for Laboratory Use. Masume Chikashige and Histoshi Matsumoto. (Joum. SOC. C‘hem. I d . , 1905, ii., 50.)-The flame of this gas is so small that it is necessary in many cases to use a far larger quantity of gas than is actually required to heat a vessel, otherwise the requisite heating surface is not obtained. The flame rapidly destroys air- and water-baths made of copper, the metal being oxidized at the high temperature of the flame. Nickel and platinum vessels are speedily damaged, probably through the alternate * Scr Jour. Sol. (,‘hoiL. Ittd., ssiii., 245.134 THE ANALYST. formation and decomposition of carbide. Porcelain vessels are also unavailable ; they become coated with a coherent deposit consisting largely of iron carbide. When burnt under a sand-bath a quantity of carbon monoxide escapes unconsumed, varying, according to the relative position of the fiame and the bath, from 0.3 to 0.9 volume per 100 volumes of gas burnt. As the volume of water-gas that must be burnt to secure the same heating effect is several times greater than that of coal-gas, the vitiation of the atmosphere is greater. In the discussion that followed Mr. David Howard suggested that many of the defects of the gas might be avoided by using Argand burners instead of Bunsen burners. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9042900125

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

134 THE ANALYST. APPARATUS. A Generator for the Continuous Preparation of Gases on a Large Scale in the Laboratory. Rsston Stevenson and W. MoKim Marriotte. (Joum. Amer. Chem. Sot., xxvi., 64.)-The apparatus shown is designed to generate hydrogen chloride gas from com- mercial hydrochloric acid, contained in the reservoir C, and strong sulphuric acid, contained in the flask D, the bottom of which is at the same height as C ; the flask D is heated on a water-bath, 0, the hot acid giving a larger and more rapid yield of gas. The two acids flow, drop by drop, through the tubes M and L, into the tower A , containing broken glass covered by a layer of glass wool. The tube I; should project against the tube M at an angle, so that the sulphnric acid may run down the tube carrying the hydrochloric acid for a lengtsh of about 5 millimetres.The gas generated passes through the tube*X into the safety flask E, from which it passes through 2 into the vessel F, or into a suitable drying-tube. The spent acids, flow through the tube Y into the carboy B, from which the tube Q leads to E, in order to equalize pressure inside the apparatus, and to obtain the remaining gas from the acids. By closing the stop-cocks N , 0, P, R, the flow of gas can be stopped a t any moment. A. G. L.THE ANALYST. 135 A Simple Thermostat for Use i n Connection with the Refkactometric Exrtmination of Oils and Fats. T. E. Thorpe. (Joum. C'hem. SOC., 1904, lxxxv., 357-259.)-The principle of the thermostat and the method of working it will be obvious from the -figure.The apparatus consists essentially of a vessel for gene- rating steam, containing a coil through which the current of water flows, and is heated before passing through the instrument shown in the drawing at Z. The vessel A is 5 centimetres in dia- meter and 5 centimetres deep, contain- ing about 100 C.C. of water. It is sur- mounted by the conical steam-chamber, B, in which the coil, C', is suspended. The diameter of the cover is 10 centi- metres. The coil is made of '' compo " tubing, about 30 centimetres long and 3 millimetres internal diameter. D is a reflux condenser, fitting tightly in the tubulure tl. The arrangement El is for maintaining a constant head of water a t the point of entrance to the coil, to avoid variations of temperature due to fluctuations in the pressure of the water- supply.F, a stout glass tube, serves as a gauge to indicate whether the over- flow and the current of water are run- ning properly. The caoutchouc tube, G, should be thick-walled to avoid loss of heat. A screw-clamp, H , regulates the flow of water through the instrument 2, and the tube, K, carries away the waste- water from the instrument. L is a, burner surrounded by a draught-protector, M, the latter having a hole, m, at its lower part, through which the gas-pipe pasees. Only a few minutes are required to bring the apparatus into action, and B steady current of water may be obtained, not varying more than 0.1" or SO in temperature throughout the day. w. P. s.136 THE ANALYST. New Lsboratory Apparatus. A. Hesse. (Chem. Zeit., xxviii., 18.) --For titratione, beaker and Erlenmeyer flasks with white enamelled bottoms are now made by Max Kaehler and Martini in Berlin.A. G. L. An Instrument for Determining the Degree of Turbidity and Depth Of Colour of Solutions. J. Konig. (Zed. fiir Untersuch. der Nahr. and Q e w s s r n i t t e l , 1904, vii., 129-141.)-The instrument, called a diaphanometer, consists of two - 0 - Eye-piece with red and green glasses I I I Reflection prism fT - - -@ Lummer Brodhun prism Compensator for loss of light in reflection prism Glass for absorbing light r* 1 I I ! I I I 1 Ground-glass plate / ,-/ .! immersion - tubes ; the light transmitted by the solution under examination passes through one tube (the right), the other tube serving as a comparison. The light from both tubes is observed through one eye-piece, each tube lighting one-half the field, after the manner of a half - shadow polarimeter.Discs of red and green glass are supplied to be inserted in the left tube, to cut-down the light until it is about equal to that transmitted through the other tube. A series of discs can also be introduced into the path, between the left-hand tube and its prism ; these cut off from 10 per cent. and up- wards of the transmitted light. The final comparison is made by raising or lowering the right-hand tube. Tables are given for converting the observations into percentages of turbidity or colour for white light, the number obtained actually denoting the percentage of light transmitted by the liquid under observation. window, the diffused light being reflected into the tubes by a ground-glass plate. Direct sunlight should be avoided. Standard glasses or solutions are not needed with the instrument. The strength of solutions of various coloured salts may be The instrument is used in front of approximately determined by this instrument. w. P. s.THE ANALYST. 137 A Back Pressure Valve for Ulse with Filter Pumps. R. N. Kofoid. (Journ. Amer. Chem. SOL, xxvi., 110.)-The body of the valve shown is made of fairly stout glass tubing. The valve itself is of the old Bun- sen type, with a glass rod, of slightly smaller diameter than the rubber tubing, wired on to prevent collapse. used should be soft. A. G. L. The rubber tubing

ISSN:0003-2654    

DOI:10.1039/AN9042900134

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

138 THE ANALYST. REVIEWS. THE PURIFICATION OF SEWAGE AND WATER. W. J. DIHDIN. Third Edition. (The The self-purification of sewage is a striking example of the perfection of Nature. After years of costly efforts to solve the problem of sewage-disposal by methods which attempted to control rather than to assist Nature, it has at length been discovered that sewage contains within itself the means necessary for its own purification, and requires only to be brought into suitable environment for those means to operate with remarkable rapidity. For much of the pioneer work required to thoroughly establish this fact the credit is due to Mr. Dibdin, who, in the volume before us, has recorded in a very interesting and able manner the results of his own observation8 and wide practical experience, together with those of other workers in this subject.After describing the nature of the foul matters which predominate in sewage, m d the processes involved in their ultimate oxidation, the author refers to some of the attempts which have been made to prevent or delay the putrefaction of sewage by antiseptic treatment, and to effect its purification by chemical precipitation, all such methods being necessarily imperfect. A r6sumd follows of the Massachusetts filtration experiments, and a full account of the experiments on the bacterial treat- ment of the London sewage at the Barking Creek outfall, which were commenced by the author in 1893, and have, since 1897, been continued and extended by Dr. Clowes, who has finally recommended the adoption of the system of bacterial treatment in coke-beds for the whole of the London sewage, after previous sedimenta- tion in tanks for a sufficient time to allow the greater part of the suspended matters to subside and become partially dissolved by putrefactive processes.I n the author’s original experiments at Barking Creek, the effluent from chemically-treated sewage was passed through a single bed of coke-breeze, but at Sutton the experiment was tried of treating raw sewage by running it first of all on to a coarse bed, and passing the more or less clarified effluent from this through a second fine bed. After two and a half years’ working it was found that this process removed the whole of the suspended matters--84 per cent. of the albuminoid ammonia, and 89 per cent.of the “oxygen absorbed,” whilst nitrification took place to the extent of 2.1 grains of nitrogen per gallon. Previous to the introduction of the bacteria beds, the average cost of treating 1,000,000 gallone of sewage had been $15 11s. Id. ; after their intro- duction this was reduced to $3 19s. Od., including pumping. I n the next chapter an account is given of the septic-tank syetems of Cameron, Scott-Moncrieff, and others, and the trickling filters of Ducat and Stoddart. The experiments carried out on behalf of the Corporations of Manchester and Leeds, of Sanitary Publishing Co., Ltd., London, 1903. Pp. 379. Price 21s. net.)TEE ANALYST. 139 which afull account is given in Chapters VIII. and IX, have proved that the sewage of large manufacturing towns is as efficiently purified by the bacterial method as that of purely residential towns, whilst Mr. William Naylor has discovered that even brewery and distillery refuse, which is 80 prone to undergo the lactic fermentation, may be successfully treated on a bacteria bed if mixed with putrid sewage.The experience of the last ten years has, in fact, established the bacterial system upon a firm basis as a acientific and practically efficient means for the disposal of the sewage of towns. Bacterial treatment in artificial contact beds depends upon the same principles as land treatment, and has the advaQtages of being independent of local conditions, under perfect control, and much more economical. When suitable land exists, the effluent from bacteria beds may be used for irrigation with much more profitable and pleasant results than if the raw or chemically clarified sewage be turned on to the land.Chapter XII. contains an interesting account of the steps by which the present method of disposal of London sewage has been arrived at, and of the immense im- provement in the condition of the Tharnes which has been effected since 1855; but until the effluent which is at present discharged into the river is bacterially treated fish life in the lower reaches will be impossible. Space will not permit of more than a reference to the subject-rnatter of the remaining chapters of this excellent book, which deale with the evils of discharging untreated sewage into the sea, the filtration of potable water, the character of the London water-eupply, the action of soft water upon lead, the absorption of atmospheric oxygen by water, the ventilation of sewers, and a summary of the interim report of the Royal Commission on Sewage Disposal, together with Appendices describing the author’s well-known method of determining suspended matter, and the principal methods of determining dissolved oxygen in water.This book contains an immense amount of information on a subject which the author has made a life-study of, and it cannot but be of the greatest value to all who have to advise upon, or are in any way interested in, this important subject. L. A. THE SALE OF FOOD AND DRUGS ACTS. By Sir W. .J. BELL, H. S. SCRIYENER, and In this new, the fourth, edition the matter of the previous one has been fully revised and brought up to date, that portion which dealt with the composition of the more important articles of food having been so modified as to no longer deserve the strictures passed on it by a previoue reviewer in this Journal.The work now includes all the more recent High Court decisions under these Acts, and also the new orders and regulations of the Local Government Board and of the Board of Agriculture. As a clear and well-arranged exposition of a very complicated subject, it cannot fail, as heretofore, to be a most useful aid to all those who are concerned in the working of the Food and Drugs and allied Acts. The general get-up of the book is excellent, C. F. LLOYD. (London : Butterworth and Co. Shaw and Sons.) and it is furnished with a copious index. IV. J. 5.140 TEE ANALYST. A LABORATORY GUIDE TO QUALITATIVE ANALYSIS WITH THE BLOWPIPE. By F. W. This work, which is intended to advance this somewhat neglected method of analysis-one which probably deserves more attention than it has hitherto received -has the merit of being short, concise, and to the point, whilst the information con- veyed is reliable. It can therefore be safely recommended for the object its author has in view. W. J. S. MARTIN. (London : Chapman and Hall. Price 2s. 10d. net.)

ISSN:0003-2654    

DOI:10.1039/AN9042900138

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

140 TEE ANALYST. INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND. AN examination in biological chemistry will be held at the Laboratories of the Institute in October, 1904. The examination will be open to candidates whose applications for admission to the final examination have been accepted by the Council, to candidates who have pawed the intermediate examination, and also to Fellows and Associates of the Institute who desire to obtain a certificate of competency in this branch of work. The examination will extend over four days, and may be theoretical, practical, written and oral. The syllabus will include biological chemistry, with special reference to the chemistry and bacteriology of foods, water, sewage, and effluents, and to the practical applications of biological chemistry to industries. The course of study recommended and copies of the exercises set at the examinations in biological chemistry held in October, 1901, and in October, 1903, can be obtained from the Registrar, 30, Bloomsbury Square, London, W.C.

ISSN:0003-2654    

DOI:10.1039/AN9042900140

出版商:RSC    

年代:1904

数据来源: RSC