摘要:

THE ANALYST. AUGUST, 1900. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. ON AN IMPROVED ABSORPTION APPARATUS FOR USE IN THE ANALYSIS OF ESSENTIAL OILS. BY ALFRED C. CHASPNAN, F.I.C., BED H. E. BURGESS. (Read at the Meeting, i4pril 4, 1900.) ABSORPTION methods involving the removal of certain active constituents of essential oils by means of appropriate reagents, and the subsequent measurement of that portion which remains unabsorbed, are of very frequent application in laboratories where these oils are examined. As examples, the estimation of citral in lemon and lemongrass oils, cinnamic aldehyde in oil of cassia, and eugenol in oil of cloves, may be mentioned. The instrument almost invariably used for such determinations is a simple glass flask capable of holding about 200 C.C.Its neck has such a capacity that it will hold 25 C.C. of the oil, and the space between the zero and the 25 C.C. mark is graduated in -k-ths, and sometimes &ths, of a C.C. This piece of apparatus is known as a Hirschsohn flask, and there are many objections to be urged against its use. In the first place, it is practically impossible to treat the oil under examination with a second quantity of the reagent, or to wash i t ; it is, moreover, impossible, as a rule, to shake the mixture in the flask with sufficient vigour for fear of obtaining an emulsion, which will not readily separate, and any insoluble matter, such as is frequently formed on shaking the oil with the necessary reagents, accumulates at the junction of the two li.quids, thus obscuring the meniscus and reducing the accuracy of the reading, an error which is further increased by the closeness of the graduations, due to the width of the neck.I t was to obviate to some extent these objections that we devised the piece of apparatus represented in the accompanying figure. It consists essentially of two parts, the flask A of about 250 C.C. capacity, and198 THE ANALYST. the measuring tube B. The latter is accurately ground to fit the flask A, and is {/TI- portion of the tube taken, from can be at once determined. arranged so that the volume intervening between the zero mark of the scale C and the mark d is exactly 25 C.C. The portion of the tube above the bulb has a considerably smaller diameter (about 5 millimetres) than that below, and is graduated downwards in 0.1 c.c., from 0 to, say, 5.The flask A has a tubulure at the bottom, through which passes a glass tube connected by indiarubber tubing to the funnel e. Communication between the two map be closed or established by means of the pinch-cock f. In using the apparatus, 25 C.C. of the oil to be analysed is pipetted at a known temperature into the flask, and is there treated with a sufficient quantity of the necessary reagent, the pinch-cock f being closed. When the soluble portion has been dissolved, the aqueous layer may be run off by opening the pinch-cock, and hot or cold water for washing purposes may be run in through the funnel e , or a further quantity of the reagent may be introduced if it is thought that the absorption has not been quite complete.The measuring tube is then fixed in position and the residual washed oil is transferred to it by running cold water through the funnel. The tube is nest fitted with a cylindrical glass jacket, water is poured into, or circulated through, it, and the oil brought to the temperature at which it was originally measured out. Then, by raising or lower- ing the funnel, the meniscus is brought exactly to the lower iiiark, and the reading on the narrow which the percentage of the absorbed constituent I t is obvious that several measuring tubes of different shapes and sizes may be fitted to the same flask, the character of the tube depending in each case on the precise purpose for which it is to be used. The tube represented in the figure is suitable for the estimation of citral in oil of lemons, or for the examination of any other oil in which the soluble constituent does not occur to the extent of more than about 20 per cent.This apparatus has now been in constant use for some months, and during that time many determinations have been made, working on artificially-prepared oils con- taining known percentages of the soluble constituents, with very satisfactory results. Since our communication was made to the Society, we have seen in a paper by Soldaini and Berte a description of a piece of apparatus intended for the analysisTHE ANALYST. 199 of lemon oil, which is very similar to ours in principle, but in which only 5 C.C. of the oil are used. So far as we are able to judge from the description, however, we are inclined for several reasons to give the preference to the apparatus described in this paper. We may add that the complete apparatus may be obtained from Messrs. C. E. Muller and Co., 148, High Holborn, London, W.C. Mr. CHAPRIAN, in reply to a question put by Dr. Lewkowitsch, said that he had had experience of the direct method of determining eugenol, based on the conversion OE the eugenol into benzoyl-eugenol, and had found that this method involved errors rather greater than those of estimation by difference.

ISSN:0003-2654    

DOI:10.1039/AN9002500197

出版商:RSC    

年代:1900

数据来源: RSC

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THE ANALYST. 199 ON THE COMPOSITION OF DANISH BUTTER. BY HAXALD FABER. (Read at the Meeting, April 4, 1900.) THE following few remarks on the composition of Danish butter were originally intended only for use in the discussion of a paper by Mr. Estcourt on “ Butter from Various Countries Compared.” Very full information of the amount of water in Danish butter is obtained by the numerous analyses made in connection with the State Butter Shows in Copen- hagen (Foreign Office Report, 1889, Miscellaneous, No. 151j. Table I., showing the amount of water found by the analysis of about 12,000 samples during nine years, calls for very few remarks. The average is about 14 per cent., most samples having from 13 to 15 per cent., and very few less than 12 per cent., or more than 16 per cent.TABLE I . XillOUNT OF TVSTEK. I N DASISH BUTTER. According to analyses of samples at the State Butter Shows. Yew13 A uerages. 1890-94 ... ... 4,458 14-32 1895 ... ... 1,517 13-70 1896 ... ... 1,992 13.68 1897 ... ... 2,016 13.79 1898 ._. ... 2,110 13.93 K‘unlber of Saniples. I’ercentagr of Water.200 THE ANALYST. Samples grouped according to Amount of Water. Percentage of Water. Number of Samples as Percentage of Total N~unber. 10-11 11-12 12-13 13-14 14-15 15-16 16-1.7 17-18 18c97. ... ... ... 0.8 ... ... ... 4.9 ... ... ... 17.1 ... ... . . . 37.4 ... ... ... 29.7 -.. ... ... 8.5 ... ... ... 1.2 ... ... ... 0.4 18\98. 0.4 2.4 12.6 37.0 35.3 10.3 1.7 0.3 The Customs have for some years taken samples of butter on landing. Dupli- cates of the samples of butter from Denmark have been analysed by Professor Stein at Copenhagen.From his reports I have compiled the following table (Table II.), showing monthly averages for the years 1898 and 1899 of the Reichert-Wollny figure, the refraction and also the number of samples which responded to the Becchi test. The chemical composition of the butter-fat as expressed, for instance, by the Reichert-Wollny figure varies with the season, the time since calving, and the treat- ment generally of the cows. In Denmark cows are generally housed from the middle of October to the middle of May, and the calving takes place in autumn and winter. Correspondingly, we find the Reichert-Wollny figure higher in the winter and spring than in summer, and lowest in the autumn, the maxima (32-6 and 32.5) for the two years occurring in Narch, the minima (24.3 and 25-61 in October. The effect of moving the cows from cold fields to warm byres in October, additional to the increased number of new-calved cows, finds its expression in a rapid rise in the Reichert-Wollny figure from October to November.I t has at last been recognised, also by the chemists of the Government Labora- tory, that the feeding of cotton-cake imparts something to the butter which reacts t o the Becchi test, and that, consequently, a cotton-oil reaction does not necessarily imply an addition of margarine. The comparison of the number of samples for the two years which gave the Becchi reaction is interesting. In 1898, which was remarkable for a luxurious growth of grass, the cows were grass-fed all through the summer, and from June to October inclusive not one sample exhibited the reaction, as no cotton-cake was used, while several samples reacted during the time the cows were stall-fed.The year 1899 was quite different ; a cold and dry spring and a dry and hot summer affected the growth of grass so unfavourably that the cows had to have some additional food nearly all through the summer, and as cotton was the cheapest cake, and Jtussian sun- flower cake (which is otherwise very much used) difficult to get, large quantities of cotton-cake were used, with the result that every fourth sample gave the Becchi reaction in summer-time, and six out of every seven responded to the test during the months of November and December. The refraction is by Zeiss's refractometer at 45" C.THE ANALYST.201 i p h e r of Reichert-Wolliiy Refraction. No11 th . amples. Figure. at 45" C. TABLE 11. STATEMENT SHOWING VARIATION IN CHEMICAL COMPOSITION OF DANISH BUTTER.* The samples analysed are duplicates of those taken by Her Majesty's Customs at port of importation. 1898. R.-W. Kecchi Test- j Max. and Min. -I January March ... 1 April ... j . * * I May ... June ... July ... ... August September 1:: i October ... November ... December . . . I None 7 16 None 14 3 None 7 16 6 16 (2) I 30.7 30.2 30.1 30.2 29.1 28.4 264 29.5 (30.0) - - 1- I - 40.4 ~ - 40*0 i 40-5 1 40.7 1 41% 42-5 1 42-7 40.5 I - I (39.4) , - 4 ' 10 1 Max. 32.6 - 9 - 7 7 9 , 9 9 ,, I Min. 24.3 5 (Max. 31.7) (1 ?> January February March April ... May ... June .. J U ~ Y ... August September October November ... I ... , ... , ... ... 1 ... ... , ... j ... None 8 (2) 17 i None ; I 9 13 3 18 - 30.7 30.8 (28.3) 29-3 (30.5) I 28.1 26.9 27.9 30.5 - 1899. I - 40.0 , 40.4 (41.5) 40.7 (40.6) 41.6 41.8 41.9 ~ 39.9 I - - 7 14 (None) 14 (1) - 1 3 2 15 Max. 32.5 Min. 25.6 (Max. 31.8) December ... I 3 30.5 40.0 ~ 3 1 PEECENTAGE O F NUMBEH, O F SAMPLES WHICFI REBCTED BY THE BECCHI TEST. 1898. 1899. January to May . * . ... 62 71 June to October ... ... 0 26 November to December . . . 33 86 * The figures included in brackets refer to samples which were so small that it way not deemed advis- able to include them in the percentage table.

ISSN:0003-2654    

DOI:10.1039/AN9002500199

出版商:RSC    

年代:1900

数据来源: RSC

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202 THE ANALYST. THE POLARIMETRIC ESTIMATION OF CAMPHOR I N CAISIPHORATED OIL. BY NORMAN LEONARD, B.Sc., F.I.C., AND H. METCALFE SXITH, F.I.C. IN a previous note on the examination of liniment of camphor (Analyst, 1898, xxiii., 272) we described two methods for the estimation of camphor in camphorated oil, one of which, yielding only approximate results, depended on a determination of the specific gravity of the liquid, whilst in the second and more accurate method the camphor was determined from the loss of weight on heating. Further experiments have shown us that by means of the polariscope the assay of camphorated oil may be effected both accurately and expeditiously. The rotatory power of camphor in its solutions in alcohol, benzene, and some other organic liquids has been studied by Landolt and others, but, so far as we are aware, no experiments have been made with olive or other oils as solvents.We have therefore examined a number of solutions prepared by digesting known weights of camphor and olive oil together at the ordinary temperature until complete solution had been effected. In the table below are given: (1) The weight of camphor contained in 100 parts of the solution ; (2) the specific gravity of the liquid at GO" F., compared with water at the same temperature; ( 3 ) the angular rotation for sodium light observed in a 200-millinietre tube with a Schmidt and Haensch half-shadow instrument ; (4) the amount by which the specific gravity is raised by each 1 per cent. of camphor; (5) the angular rotation per 200 millimetres for each 1 per cent.of camphor. The olive oil used in the preparation of the solutions had a specific gravity 0.91666, and a rotatory power +0-13" per 200 millimetres. The latter figure was deducted from the observed rotations of the solutions in calculating the numbers in the fifth column of the table. The last solution was a saturated one prepared by gently warming olive oil with excess of camphor, cooling to about 10" C., and filtering; the camphor in it being determined from the loss of weight sustained on heating at 110" to 120" C. : 1. 2 . 3. 4. 5. Specific Rotation Specific Gravity Rotation per Gravit.y per 200 raised per 200 Rlillimetres a t 60" F. Xillimetres. 1 per cent. per 1 per cent. Camphor per cent. 5.32 091903 + 5.26" 0.000446 0.964" 11-26 092173 + 11-35" 0*000450 0.996" 20.66 0.92604 + 20.i4" 0.000454 0 998" 26.78 0.92911 + 26.79" 0 a000465 0'-996" It will be seen from these results that the rotation is increased by nearly 1" for each per cent.of camphor present, and that the observed rotation of a sample of camphorated oil in a 200-millimetre tube gives at once, without calculation, the percentage of camphor with sufficient accuracy for most purposes. The rotation appears not to be appreciably influenced by ordinary variations of temperature. According to Bishop (Journal of the Society of Chemical Industry, 1887, p. 750), olive oil has a rotatory power +0*13" per 200 millimetres, and several specimens examined by us have given values closely approximating to this, values too small to affectTHE ANALYST.203 seriously the optical estimation of camphor dissolved in such oils. In the case of some other oils which are occasionally substituted for olive oil in liniment of camphor the rotatory power is greater. Thus, we have found the rotation of two specimens of rape oil to be -0.16" and -0.3", and of sesame oil +1-6", per 200 millimetres, results which are in accord with those of Bishop, whilst two samples of fluorescent mineral oil gave rotations of + 0-12" and + 0.42". Experiments with rape oil and mineral oil have shown us, however, that the increased rotation caused by the solution of camphor in the oils is practically the same as with olive oil, so that if the natcre of the oil used in the preparation of the sample is known, the process is still applicable.With regard to the identification of the oil used, we have found that the sample may be examined directly with the refractometer, the refractive index of the oil being apparently almost unaffected by the presence of dissolved camphor. I t is worthy of notice that the specific rotation of camphor in its solutions in olive oil is shown by our experiments to be about +54", a higher result than is given by any oE the solvents examined by Landolt, and approximating to the value ( + 55.4") calculated by hiin for the absolute specific rotation of camphor. Since writing the above, our attention has been called to an account of some experiments by E. Dowzard (British Food Jownal, 1900, p. 69), who finds, by comparing the rotatory power of a number of samples of camphorated oil with the amount of camphor '( ascertained by the gravimetric process," that the angular rotation per 100 millimetres multiplied by the factor 1.962 gives the percentage of camphor in the sample. We are indebted to Dr. Thomas Stevenson for permission to use results obtained in his laboratory. NOTE.-we are indebted to Mr. A. H. Allen for informing us, in a private com- munication, that P. Chabot (Compt. rend., cxi., 231, and Journal of the Chemical Society, Abstracts, 1890, 1427) had previously determined the rotatory power of camphor when dissolved in various oils. A 20 per cent. solution in olive-oil gave the value +55" 12', and this also agrees fairly with our own results. This result is in fair agreement with our own experiments.

ISSN:0003-2654    

DOI:10.1039/AN9002500202

出版商:RSC    

年代:1900

数据来源: RSC

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THE ANALYST. 203 ABSTRACTS OF PAPERS PUBLISHED IN OTHER J 0 U R N ALS. FOODS AND DRUGS ANALYSfS. Foreign CoPouring Natter in Milk. A. E. Leach. (hu?%. dmer. Chem. soc., vol. xxii. [4], pp. 207-210.)-To detect foreign colouring matters the author curdles 150 C.C. of the suspected milk by the aid of heat and acetic acid, the curd being collected in a lump by means of a stirring-rod, or else separated by straining through a sieve. The whole of any annatto or aniline-orange and a portion of any caramel colouring matter employed will be retained by the curd, which is next broken up and treated with ether for the extraction of fat and annatto. The residual curd will be204 THE ANALYST. white if the milk has not been artificially coloured, or if only annatto has been used ; whereas caramel will leave a brown curd, and aniline-orange a more or less bright orangs tinge.Annatto can be separated from the ethereal extract by evaporating the latter, making the residue alkaline with sodium hydroxide and pouring it on a wet filter, which will absorb annatto and acquire a fairly permanent orange tint, turning to pink in presence of stannous chloride. Caramel may be regarded as present if the coloured curd from which the fat has been extracted yields a deep blue coloration on agitation with concentrated hydro- chloric acid, such as the white fat-free curd of an uncoloured milk would give,” and may then be confirmed by any of the usual tests on a fresh sample of the milk. When aniline-orange has been employed the acid treatment develops a pink colora- tion immediately.c. s. Artificial Cooking Fat and its Digest,ibility in Comparison with Lard. H. Liihrig. (Zeit. .fiir Unterszich. der NcLhr. m d Genussnzittel, 1900, iii., 73-87.)- This paper is a further instalment of the author’s researches upon the digestibility of various fats (cf. ANALYST, 1899, xxiv., 237 and 283). Two preparations of cooking- fat were examined and compared as regards digestibility with lard. Preparation I. consisted of tallow and cotton-seed oil; Preparation 11. of tallow, cotton-seed oil and lard, both being productions of a well-known margarine factory. The methods pursued were mainly the same as described in the author’s previous communications. The following coefficients of digestibility were obtained : for lard, 96.36 ; for Preparation I., 96-09 ; for Preparation II., 96.47.H. H. B. S. The Detection of “Vinoline” and Bordeaux Red in Wines. A. Casali. (Stax. Sperinzeizt. Itnl., 1900, xxxiii., 183-189.)-1n the author’s experience the artificial coloration of Italian wines is at the present time a very general practice, those from the central provinces being chiefly coloured with “ vinoline,” and those from the south with Bordeaux red. The name “vinoline” is not applied to a single colouring matter, but usually denotes a mixture of different coal-tar reds. In Italian wines the author has found it to consist to a large extent of salts of rosaniline, such as the hydrochloride, acetate, nitrate, and (more rarely) the sulphate. I n order to detect these, 100 C.C. of the wine are rendered strongly alkaline with ammonium hydroxide, and after the addition of a few drops of it solution of sodium hydroxide, shaken for a long time with 30 C.C.of chloroform. The solution of the colouring matter in chloroform becomes red on acidification, and when allowed to spontaneously evaporate leaves a scarlet residue. Wines coloured with Bordeaux red (azo-naphthyl-naphtol-sulphonic acid) differ from those coloured with ‘‘ vinoline ” in giving a turbidity on the addition of hydro- chloric acid. To detect this, 50 to 100 C.C. of the suspected wine are treated with 10 to 20 c.c, of a 10 per cent. solution of barium chloride, and sufficient potassium bisulphate * In order to obtain this reaction, which is hastened by gentle heat, it is necessarythat the curd should be thoroughly freed from fat.THE ANALYST.205 solution to precipitate the barium salt. When the precipitate has subsided, the super- natant liquid is decanted, and after the addition of 3 to 6 C.C. of hydrochloric acid and sufficient water to bring it to its original volume, it is boiled for 5 to 10 minutes with a few fibres of fat-free wool. In the presence of Bordeaux red the wool is dyed a bright-red colour, which does not alter on adding ammonium hydroxide. I n certain cases the colour appears to be carried down with the precipitate, and the wool, when boiled with the deposit and washed, assumes, on treatment with alkali, a green tint, which changes to red on again mashing with water. "Vinoline" colours which are not in the form of salts do not behave like the dyes mentioned above, but can be readily extracted from the wine by means of hot amyl alcohol.This extraction can be made even when 9 to 11 per cent. of alcohol are present and in the presence of acetic or hydrochloric acid. The wool dyed red in the amyl alcohol solution becomes green on treatment with ammonium hydroxide, and again red when washed with water. When dried and digested with dilute hydrochloric acid it colours the liquid violet-red-a property which distinguishes it from wool dyed with Bordeaux red. C. A. M. __ - _. -~ Cider Vinegar; its Solids and Ash. R. E. Doolittle and W. H. Hess. (Jour?~. Anzer. Chem. Xoc., vol. xx., [a], pp. 218-220.)-Two samples of imitation cider vinegar containing the statutory percentages of solids and ash were found on examina- tion to furnish an evaporation residue resembling molasses, and of sharp acid odour, whereas the solids from the genuine vinegar are light and foamy in appearance, with an aroma of baked apples.The following results were obtained on analysis : ~ ~ ~ ~ _ _ _ _ ~ --__ ' Pure Cider 1 2zi:e Suspected Vinegar. - , Vinegar. I 1 2 Vinegar. Per cent. ~~~ _ _ ~ - ___--------- Per cent. I Per cent. 1 Per cent. Solids : I I I Reducing sugar, before inver- j sion.. . ... ... ... 1 0-14 0 42.88 56.82 ' 0 1 33.36 57.04 sion ... ... ... ... 0-10 Reducing sugar, after inver- I I Polarization, before inversion Polarization, after inversion CaO ... ... ... ... MgO ... ... ... ... K,O ... ... ... ... Na,O ... ... ... ... so, ... . . I ... ... P,O, ... ... ... ...Ash coizstituents : 0" 0" Per cent. 3.4-8.21 1.88-3-44 46.33 - 65-64 trace 4.66-16-29 3-29- 6.66 0" /+40*$" I-31.14" 0" l+38*8" 1-34-25' Per cent. Per cent. 1 Per cent. 4.73 4.70 37.95 4.12 2.00 ~ 2.22 37-00 nil 7-84 trace 49.71 trace 34-75 1 27.04 1 12.74 9-66 1 0.005 1-82 ~ Boiled Cider. Per cent. 61.12 66-45 - 17.9" - 25.0" Per cent. Fe,O, ... ... ... ... trace trace I trace I 1.60 COs, loss, etc. ... ... 40-44-0 1 9.64 ~ 16.54 35.83 ~ _- The suspected sample No. 1 was therefore compounded of dilute acetic acid, glucose and soda ash ; No. 2 of acetic acid, boiled cider, and lime. c. s.206 THE ANALYST. The Detection of Foreign Colouring Matters i n Praserved Tomatoes. G. Halphen. 1. Coal-tar CoZours.-The usual method of testing for these consists in mixing the tomato-pulp with dilute ammonium hydroxide, extracting it with amylic alcohol, and evaporating the extract in the presence of undyed silk.I n the author’s experience this has not proved satisfactory, partly on account of the readiness with which certain colouring matters become attached to the vegetable fibres, and partly because the particles of tomato prevent the solvent from coming into contact with the colour. He has obtained better results by extracting the desiccated pulp with ordinary alcohol from an acid medium. An addition of an equal volume of sand or precipitated silica is advantageous during the drying, which in certain cases should take place at the ordinary temperature in order to prevent the possible decomposition of unstable azo-compounds.In very many cases, however, the mass may be dried on the water-bath. The dried substance is pulverized, transferred to a flask, and covered with glacial acetic acid. The mass is well stirred and the flask closed, and left for ten minutes. The liquid is then mixed with twice its volume of alcohol (90 per cent.), and again allowed to stand. After ten minutes it is transferred to a filter, and the filtrate collected in a 250 to 300 C.C. flask. After the addition of ten times its volume of water, a small knot of flossy silk is introduced, and the liquid boiled for at, least fifteen minutes. In the absence of coal-tar colours the silk becomes slightly yellow or brown, without any trace of red or rose; but in the presence of these dyes it assumes a rose-red or salmon colour.2. Cochi.laea.Z.-According to the author, this is always used in the form of a lake, and as these lakes are often not attacked by glacial acetic acid, it is frequently possible to detect the dyes in the residue left on the filter in testing for coal-tar colours. It is preferable, however, to use a fresh portion of the tomato, which is mixed with silica and dried on the water-bath. The dried residue is thoroughly mixed with pure hydrochloric acid (specific gravity 1-16 to 1-17), and after being left for ten minutes the paste is shaken with twice its volurne of 90 per cent. alcohol, allowed to stand for ten minutes, and filtered. The filtrate is mixed with at least ten times its volume of water, and is shaken with sufficient amylic alcohol to form a layer of not less than 5 C.C.when the liquids separate. The lower aqueous layer is withdrawn, leaving the carminic acid and part of the natural colouring matter of the tomato in ehe amylic alcohol. I n order to separate these, from 1 to 1-5 times the volume of carbon bisulphidt: and 4 to 5 times the volume of water are added to the amylic alcohol, and the mixture shaken with a circular motion. After standing, the lower layer is removed and the upper aqueous layer filtered. When cochineal has been used the 6ltrate will have a rose colour, with more or less of a yellow shade, and on shaking with 2 or 3 C.C. of amylic alcohol the colouring matter can be extracted, forming a yellowish- red solution. The amylic alcohol solution is tested with a drop of a concentrated solution of uranium acetate, and on shaking gives a characteristic green coloration.C. A. M. (Journ. Pharm. Chim., 1900, xi., 169-172.)THE ANALYST. 207 The Occurrence and Estimation of Tin in Preserved Meat. F. Wirthle. (Clzem, ZeCt., 1900, xxiv., 263.)-The author has recently had the opportunity of investigating some samples of tinned meat, one, two, three, and four years old, which had been preserved in vessels of tin-plate with folded seams, solder not being used. He found that the proportion of tin in the food slightly increased during the time of keeping after the second year, but between the first and second year there was a minute falling off in metallic contamination. He also corroborated Giinther’s state- ment that the amount of tin in the meat itself is about two or three times as much as in the liquor.His maximum figures were obtained on a sample four years old, where the meat gave 0.0094 per cent., while another specimen of beef of the same age gave 0.0082 per cent. in the meat and 0.0028 per cent. in the juice. A sample of beef five years old, on the other hand, contained 0.0325 per cent. of tin, and the liquor 0-014 per cent., the inner surface of the vessel being completely destroyed. Corrosion of the can occurs mainly where it comes in contact with the fat ; and the white deposit noticed in bad cases consists of basic stannous chloride. For the determination, 120 grammes of meat (or liquor and fat) are heated in a porcelain basin over an asbestos plate with 5 C.C. of strong sulphuric acid ; the mixture is stirred at intervals, and more acid (altogether 15 or 20 c.c.) is dropped in gradually, until a porous carbonaceous mass is obtained. This is powdered and rinsed with dry sodium carbonate into a porcelain crucible, more sodium carbonate and some nitrate are added, and the whole is fused. The melt is extracted with water and a current of carbon dioxide is passed through the liquid. When clear, the precipitate is collected, washed, dried, and ignited, then heated in the covered cruoible with potassium cyanide to a dull-red heat. The mass is treated with water, the metallic iron and tin filtered off, and dissolved in warm hydrochloric acid. The tin is precipitated with sulphuretted hydrogen, collected, washed with sulphuretted hydrogen-water con- taining some ammonium nitrate solution, dried and ignited with the paper to constant weight. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN9002500203

出版商:RSC    

年代:1900

数据来源: RSC

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THE ANALYST. 207 ORGANIC ANALYSIS. The Detection of Benzene in Alcohol. G. Halphen. (Jounz. Plaarm. Chim., 1900 xi. 373-375.)-As it has been proposed in France to denature alcohol for commercial purposes by the addition of benzene oils the question has arisen as to whether it is possible to detect the presence of benzene in the alcohol recovered from such denatured products. The author finds that the following method is extremely sensitive and gives good results. It consists in isolating the hydrocarbons and converting them into diazo-compounds which combine with naphthols to form coloured compounds. From 10 to 20 C.C. of the spirit under examination are shaken with 5 to 10 C.G. of carbon bisulphide in a separating funnel and after the addition of ten times the volume of sodium chloride solution (about 20 per cent.) the funnel is inverted several times and allowed to stand.The lower layer of carbon bisulphide is withdrawn Etnd the hydrocarbons nitrated by the addition of 0.5 to 1 C.C. of a mixture of 10 C.C. of Nordhausen sulphuric acid and 1 C.C. of fuming nitric acid the liquids being stirre 208 THE ANALYST. together for two or three minutes. The supernatant carbon bisulphide is then decanted 5 C.C. of water added the rise in temperature produced accelerating the separation of the last portions. The acid layer is diluted with 15 to 20 C.C. of water and shaken with 4 or 5 C.C. of sulphuric ether in order to remove the nitro-compounds which are nearly in-soluble in water. The residue left on evaporating this extract is treated with 20 C.C.of water acidulated with hydrochloric acid (5 to 10 per cent.) then with one drop of a solution of platinic chloride and 0.2 to 0.3 gramme of zinc dust and the evolution of hydrogen continued for at least ten minutes. The liquid which should still be acid is filtered and when cold is treated.with 4 or 5 drops of a 10 per cent. solution of sodium nitrite and after ten seconds the excess of acid neutralized by a slight excess of sodium carbonate. The solution with the zinc carbonate in suspension is then tested with a few drops of an alkaline solution of a-naphthol which in the presence of nitrobenzene, produces an orange-red coloration. Similar colorations are also obtained with the nitro-compounds of the higher homologues of benzene. C. A. M.A Comparison of some Formaldehyde Tests. B. M. Pilhashy. (Jozbrn. Amer. Chem. SOC. vol. xxii. [3] pp. 132-134.)-The author finds that the following reagents recommended for the detection of formaldehyde viz. Schiff‘s (fuchsine and sulphurous acid) phenol and sulphuric acid diazobenzene-sulphonic acid and Nessler’s solution also give reactions with other aldehydes whilst the coloration produced by dimethylaniline and sulphuric acid (Trillat) is due t o the dimethylaniline alone. Lebbin’s test he finds unreliable below the limit of 1 200,000 whilst the limit of delicacy of the morphine hydrochloride test is 1 1000. On the other hand phenyl-hydrazine hydrochloride forms the best test a decided green coloration being developed in half it minute in a 1 100,000 solution and in ten minutes with a 1 250,000 solution.For the same reagent in conjunction with sodium nitrocyanide and concentrated sodium hydroxide the limit of sensitiveness seems to be about 1 1,000,000. c. s. Two Deceptive Reactions. C. Amthor. (Zeit. fur Uwkrsuch. dey Nahr. und Genussmittel 1900 iii. 233-235.)-Detection of PormaldeJzylde.-The author has studied the colour reaction with hydrochloric acid which Leonard and Smith supposed to be indicative of milk containing formalin but which Fisher pointed out was also obtained with milk containing boric acid (ANALYST xxiv. 86). He finds that the reaction is neither characteristic of formaldehyde nor of boric acid but is equally well produced when both bodies are absent. He ascribes it to the presence of albuminous bodies in conjunction with sugar (cane-sugar milk-sugar dextrose etc.).With sour milk owing to the small quantity of sugar remaining therein the reaction is weak but it becomes immediately stronger on the addition of a little milk-sugar THE BNALYST. 209 The reaction can also be produced with meat or egg-albumin but here also the addition of a little sugar is necessary to produce a strong reaction. Detection of Sesame Oil.-The author found that the reaction above referred to was frequently obtained with butter owing to the presence of small quantities of casein and milk-sugar and that when only slight it could be intensified by the addition of milk-sugar. Further that the same effect was produced when furfurol was substituted for sugar. The fact is of importance in connection with the detection of sesame oil in butter by means of furfurol since unless the casein be previously completely removed by filtration or other means the reaction may be obtained in the complete absence of sesame oil.H. H. B. S. Note on the Estimation of Formic Acid in the Presence of Acetic Acid. F. Sparre. (Zeit. anal. Chem. 1900 xxxix. 105 106.)-The method given by Leys (Zeit. ana2. Chem. xxxviii. 677) which consists in heating the liquid with mercuric oxide suffers from the drawbacks that the flask must be allowed to stand overnight, and that the precipitate must be filtered washed dissolved in nitric acid precipitated with sodium chloride and estimated gravimetrically. I n the author’s experience the method of Portes and Ruyssen is less tedious and equally accurate.In this 5 grammes of sodiuni acetate 25 C.C. of a 1 per cent. solution of the liquid under examination and 200 C.C. of a 4.5 per cent. solution of mercuric chloride are heated in a flask for one to one and a half hours on the water-bath and then diluted to 500 C.C. and filtered. The amount of formic acid is then calculated from the number of C.C. of the liquid required to produce a red coloration with 1 gramme of potassium iodide. C. A. M. A New Reagent for Phenolic Bodies. G. Candussio. (Chem. &t. 1900, xxiv. 299.)-This reagent consists of a 1 per cent. solution of potassium ferricyanide, containing 10 to 20 per cent. of ammonia; and its effect on various phenols, etc. is shown in the paper side by side with that of a 10 per cent.solution of ferric chloride. The tests are carried out in three ways by adding the reagent drop by drop to the phenol ; by dropping the phenol into an excess of the reagent ; and by making the phenolic solution alkaline with sodium hydroxide and then adding the reagent. Potassium ferricyanide exhibits several advantages over ferric chloride ; and in particular it can be used on an alkaline or faintly acid liquid without previous neutralization so that in the examination of essential oils or in physiological and pathological work it is distinctly preferable. Reducing bodies such as sodium phosphite and hypophosphite formaldehyde and especially sodium sulphite destroy the reactions precisely as happens with ferric chloride. F. H. L. The Theory of Saponification.J. Lewkowitsch. (Bel-ichte 1900 xxxiii., 89-99.)-Geitel came to the conclusion that during the saponification of fats and oils mono- and di-glycerides are produced as intermediate products but Henriques (ANALYST 1898 290) was unable to obtain any confirmatory evidence of this. The author has therefore made a large number of experiments in order to settle th 210 THE ANALYST. question. In these several pounds of tallow and of cotton-seed oil were saponified with sodium or calcium hydroxides in the same way as in the ordinary manufacturing process. From time to time samples were withdrawn treated with hydrochloric acid, and washed and dried. The acetyl value and the Hehner and saponification values of the acetylated product were determined whilst the amount of free acid calculated From the acid value showed to what extent the saponification had progressed.The line of reasoning followed was that if the saponification only produced glycerin and fatty acids the acetyl value of the partially saponified fat should not exceed that of the original f a t ; but if on the other hand lower glycerides were formed as intermediate products these having a definite acetyl value would cause an increase in the acetyl value of the samples (cf. ANALYST xxiv. 326). Confirmatory evidence would also be obtained from the Hehner and saponification value of the acetylated product which would show great variations in the presence of mono- or di-glycerides. The experiments proved that the acetyl values rose and fell with the progress of the saponification whilst at the same time the Hehner and saponification values of the acetylated products showed a corresponding variation.The author therefore, has arrived at the conclusion that there can be no doubt that the saponification process takes place in stages and that it must be regarded not as a tetramolecular change but as a bimolecular reaction in agreement with the views of Geitel. As a typical example the following results of one of the experiments may be quoted : SAPONIFICATION OF COTTON-SEED _ _ ____ .__ ~ _ _ _ _ _ _ _ __ Original oil acetylated Partially saponified oil : . . . 1. . . . 2. . . . 3. . . . 4. . . . 5. . . . 6. . . . 7. . . . Fatty acids obtained by saponification with alcoholic ~_ _-KOH acetylated . . __ __ -~ __ -~ ~ - __ Acid Value.0.0 - - __-__ 0.5 0.6 16.0 17% 19.9 53.4 73.2 199.45 OIL WITH CALCIUM HYDROXIDE. - - - _ ~ _ _ _ _ _ ~- __ _ ACETYLATEI) PHODUCT. Acetyl Value by Filtration Process. 11.7 14.9 20 *o 43.15 59.2 28.3 ! 24-9 32.4 Hehner Value. 93.5 94.5 92.84 92.0 89.1 92.35 93.8 93.6 99.4 Saponification Value. 206.3 209.2 230.1 240.0 215.3 214.8 223.4 216.4 Of this experiment the author remarks that the fairly rapid rise of the acetyl value with at the same time the slower rise of the acid value indicates the pre-dominance of the first or first two steps in the saponification whilst the subsequent rapid decrease in the acetyl value points to the decomposition of the monoglycerides predominating THE ANALYST 211 It is pointed out that in such experiments as these only the mean values of the concurring phases of the saponification are determined since simultaneously a molecule of diglyceride may be converted into monoglyceride and fatty acids or a moIecule of monoglyceride into fatty acids and glycerin while a molecule of triglyceride is only passing through the first stage.I n one of the experiments the saponification proceeded with such rapidity that but for the fact that a higher acetyl value was obtained with one of the first samples, the results might have appeared to support the older view of saponification. C. A. M. Volumetric Estimation of Fatty Acids. J. Swoboda. (Chem. Zeit. 1900, xxiv. 285.)-Standard alcoholic solutions of alkali hydroxides have the disadvantage of not retaining their strength for long ; whereas in the titration of fatty acids aqueous alkalis are inconvenient because of the precipitation of the fatty matter.The author suggests that fatty acids should be dissolved for titration in a mixture of 1 part of absolute ethylic alcohol and 2 parts of amylic alcohol to which liquid an aqueous alkali may be added without causing separation and in which the colour of the indicator is perfectly distinct. F. H. L. Mixtures of Maize Oil with Cotton Oil. G. Morpurgo and A. Gotzl. (Oestew. Chem. Zeit. 1900 iii. 53.)-Inasmuch as cotton oils with a low solidifying point are greatly sought after and fetch a high price an addition of maize oil is quite possible although its price is higher than ordinary cotton oil.The authors give a table of the constants of both oils as obtained from the examination in duplicate of four separate brands of American cotton and two brands of maize oil the figures '( agreeing fairly well " (sic ; cf. however ANALYST 1899 xxiv. 16) with those already quoted by De Negri and others. The most prominent differences between the oils are found in their iodine values and the melting-point of their fatty acids and the following table represents these constants in the case of the genuine oils and in various mixtures thereof : Cotton oil mean figures" . 4 parts cotton oil + 1 part maize oil 3 9 9 ? + 1 7 2 , 2 1 7 +I 7 9 7 1 part , +1 ) ? 1 7 7 9 + 2 parts 7 7 Maize oil sample No. 1 . I , No. 2 . Iodine Value.. 106.47 . 107.40 . 110.80 . 112.05 . 115.70 . 118.30 . 147.60 . 124.50 Melting-point of Batty Acids. 36-37" 36-37" 35-36' 34-34.5" 31-32' 29-30" 18-20" 18-20" Maize oil does not give the Becchi reaction so that additions of cotton oil can be detected in this manner. Taste and smell cannot be relied upon hot-pressed cotton oil is much like roasted maize oil ; sometimes however the latter is practically odour-€ess. The acid value of pure commercial cotton oil is generally under 1 and it does not increase much when the oil becomes rancid ; maize oil oxidises more readily so that an excess of free acid points to the presence of maize oil in cotton oil. F. H. L. * Extreme figures 104.45 and 107.61 212 THE ANALYST. The Detection of Cotton-seed Oil by the Pentosan Reaction.B. A. van Kettel. (Monit. Scientif. 1900 xiv. 154-156.)-1n a former communication (Ber. Nederl. Maatschap. Pharm. October 1897) the author described a test based upon the fact that vegetable oils and notably cotton-seed oil contain traces of pentosans, whilst animal oils are free from such substances. Ten grammes of the oil are heated with a few C.C. of hydrochloric acid (specific gravity 1.06) until permeated with the acid vapours. The tube is then left for 10 minutes for the liquids to separate and on now adding a solution of phloroglucinol hydrochloride a red ring is formed at the juncture of the layers in the presence of pentosans. Among the oils which do not give the pentosan reaction are cacao oil earthnut oil croton oil rape-seed oil and linseed oil.Two specimens of pure olive oil examined by the author also gave negative results. I n the present paper the results of this test are compared with those of Halphen’s and Cavalli’s reactions. The latter test consists in shaking the oil with a mixture of 2 grammes of resorcin 20 C.C. of water and 15 C.C. of sulphuric acid a red coloration changing to blue being given by cotton-seed oil. Six specimens of cotton-seed oil of different origin and a specimen of cotton “ stearin ” were tested. With Halphen’s reagent all gave a red coloration with the exception of a crude yellow Egyptian oil. With Cavalli’s reagent only two of the oils gave a pronounced reaction and one a faint coloration. With the author’s pentosan reagent five of the samples including the Egyptian oil gave a marked coloration and the other two a faint reaction.The crude Egyptian oil mas treated with animal charcoal and the filtrate tested with Halphen’s reagent but as the red coloration was still not obtained the conclusion was arrived at that this oil did not contain the substance producing the react ion. I n view of the results of these experimeuts Cavalli’s test was regarded as unreliable. The author found that his own reagent was capable of detecting 10 per cent., and sometimes 5 per cent. of cotton-seed oil in earthnut oil. Holde and Pelgry have shown (ANALYST sxiv. 214) that cotton-seed oil after being heated at 220-225” C. no longer reacts with Halphen’s reagent. The author has tested his pentosan reagent on the six oils mentioned abov8 after heating them for 30 to 40 minutes at about 250” C.Only two gave a coloration with Halphen’s reagent whilst with the author’s reagent two gave negative results four faint reactions and one a pronounced coloration. C. A. M. Separation of the Constituents of Rancid Fats and Oils. J. Nagel. (Amer. Clzem. Journ. 1900 xxiii. 173-176.)-The following classes of compounds were identified by the author in his investigatiou on the rancidity of fats and oils (1) Free fatty acids (saturated and unsaturated). (3) Lactones and anhydrides of fatty acids. (4) Alcohols such as butylic amylic and caprylic alcohol. (5) Esters of saturated unsaturated and hydroxy-fatty acids with higher and sometimes also polybasic alcohols (6) Aldehydes (saturated and unsaturated).(7) Acetals and (8) Terpenes. (2) Hydroxy-fatty acids THE ANALYST. 213 I. Separation of Saturated Unsaturated and Hydroxy dcids.-These were neutralized with a solution of soluble glass instead of with alkalies with the result that emulsions were avoided the silicic acid liberated in the reaction drawing the alkali salts mechanically to the bottom. 11. Separation of Ladones.-Those lactones which were volatile with steam were removed simultaneously with terpenes by distillation as in VI. Non-volatile lactones were converted into salts of hydroxy-fatty acids by boiling the oil from which the free fatty acids had been removed with a concentrated solution of an alkali. 111. Alcohols and Esters when volatile with steam were removed as described under VI.IV. Separation of ,4ldehydes.-When volatile these were removed by distillation. To separate the non-volatile aldehydes 4 volumes of the oil were heated for an hour with 1 volume of a concentrated solution of sodium bisulphite and the aqueous layer separated on cooling. The compounds of the aldehydes with sodium bisulphite being slightly soluble in the solution of bisulphite were removed together with the solution. V. Separation of Acetals.-Where these were not volatile with steam it was found best to decompose them into alcohols and aldehydes by heating the fat with dilute sulphuric acid. VI. Separation of Terpenes.-These were removed by distillation being all volatile with water-vapour. In order to prevent further changes in the oil by the prolonged action of steam at 100" C.and of atmospheric oxygen the steam was either passed through the oil together with a neutral gas or was gradually super-heated (100' to 170" C.) and accompanied by an inert gas. In fractionating with superheated steam the most volatile substances passed over before the more highly-heated steam which would have decomposed them was introduced. The oil was subsequently cooled in uacuo or in an atmosphere of an inert gas such as hydrogen The resulting insoluble salts were separated by filtration. The resulting compounds were removed as in IV. or VI. or carbon dioxide. In conclusion, of his investigation the author describes a method of practically applying the results to the purification of rancid fats and oils on a large scale.C. A. &I. Macassar Oil. J. J. A. Wijs. (Chenz. Rev. Fett. u. Haw-Ind. vol. vii. [3] pp. 46, 47.)-A sample of the butter-like fat obtained from the seeds of Schleichera trijuga Willd. by extraction with benzene furnished the following constants Melting-point (Le Sueur and Crossley's method) of the fat 22" C. ; of the fatty acids 52" to 54" C. ; Hehner value 91-55 ; saponification value (Henriques' cold method) 215.3; iodine value (Wijs' method) of the fat 55.0; of the fatty acids 513.9; Reichert-Meissl value 9 ; acid value of the fat 19.2 ; of the fatty acids 191.2 to 192 ; percentage of unsaponifiable matter 3-12 per cent. The seeds yielded 40 per cent. of kernel containing 70.5 per cent. of fat 3.5 per cent. water and 12 per cent. protein. The volatile acids examined by the Duclaux method were found to consist of acetic acid with a small quantity of a higher acid probably butyric by the odour of the ester furnished on treating th 214 TEE ANALYST.distillate with alcohol and sulphuric acid. Of the non-volatile acids 45 per cent. consisted of solid fatty acids and 55 per cent. of liquid acids having the iodine value 103.2. c. s. The Composition of Japan Wax. A. C. Geitel and G. van der Want. ( JO.UWZ. prak. Chem. 1900 lxi. 151-156.)-Considerable variations were found in the constants of four specimens of the commercial wax examined by the authors. The acid value fluctuated between 21.7 and 32.6 ; the saponification value between 217.5 and 237.5 ; the iodine value between 8.3 and 8.5 ; and the amount of unsaponifiable matter between 1-48 and 1-63 per cent.In two different samples 90.62 and 90.66 per cent. of insoluble fatty acids and 4.66 and 5-96 per cent. of soluble fatty acids, were respectively found. The soluble fatty acids had the consistency of lard; their acid value was 3452, and their mean molecular weight 162. In the authors' opinion they consisted of a mixture of fatty acids produced by the action of the oxidizing agents employed to bleach the wax. The insoluble fatty acids had an acid value of 212.2 to 215.7 and an iodine value of 10.6. By fractional precipitation with magnesium acetate they were separated into palmitic acid oleic acid contaminated with unsaponifiable matter, and a fatty acid melting at 117" C. to which the authors gave the name of J a p z i c acid.This acid when purified by recrystallization from alcohol or chloroform melted at 117.7" to 117.9" C. I t was found to be saturated and to contain no hydroxyl groups. Its molecular equivalent, as found by titration was 186.2 but by the boiling-point method its molecular weight was found to be 365. The conclusion finally arrived at was that it belonged to the succinic acid series and had the formula C,~€I,O(COOH)~. By recrystallizing the wax from hot benzene a hard wax-like substance melting at 43" to 45" C. and with an ester value of 252.6 was eventually obtained. As a glyceride containing one molecule of Japaizic acid and one molecule of palmitic acid would have an ester value of 253.4 the authors considered it highly probable that this acid is present in Japan wax in the form of a mixed glyceride.A reference is made to the abnormal behaviour of the fatty acids of Japan wax when dissolved in a saturated alcoholic solution of stearic acid (ANALYST xxi. 330). C. A. M. I t could be dried without loss at 115" to 120" C. Notes on Commercial Glycerin. (Zed. anal. Chem. 1900 xxxix., 95-99.)-The author gives a detailed account of a number of experiments from which he has arrived at the following conclusions : I€. Struve. 1. The purest glycerin in the market contains from 6.02 to 8 per cent. of water. 2. Commercial glycerin does not lose the whole of its water when dried in tmcuo, 3. The most anhydrous glycerin is hygroscopic and absorbs moisture from the 4. Traces of glycerin are volatile in a current of steam.I n one experiment the but retains 1-52 per cent. atmosphere up to 17.46 per cent. loss on distillation amounted to 0.379 per cent. C. A. M TEE ANALYST. 215 Some Properties of Rosin. A. Smetham and F. R. Dodd. (Jo?LT. XOC. Chem. Id. 1900 xix. 101.)-The authors call attention to the fact that the constants of colophony acids are not the same as those of the rosins from which they have been derived ; therefore in the analysis of soaps especially those containing much rosin, it is not possible to calculate accurately the proportion of colophony used by the manufacturer by comparing the analytical data with the figures published for ordinary rosin. The annexed table gives firstly some constants of various brands of commercial rosin and secondly the similar constants of the same materials after saponification decomposition of the soaps and removal of the resinous matters by means of ether.* The iodine values were obtained with the Hubl solution at eighteen hours employing an excess of 300 per cent of iodine.BRANDS. (‘ w. w. “N. C‘W. y. Zante.” Xeres.” Wax. “Wite.” ‘‘ Nerno. ” Original rosin : Acid value . . . . 160.8 162.0 154.5 157.3 160.1 Saponification value . . . 177-6 176.4 174.3 174.3 177-3 Iodine value . . . . 184-7 181.0 158.5 168-4 165.9 Acid value . . . . 163.9 163.9 159-1 159.1 161.0 Saponification value . . . 176.4 175.3 167.5 165.5 169.5 Iodine value . . . . 175.5 166.8 154.9 149.9 153.6 Recovered resin : The authors agree with Lewkowitsch that the elfect of the Wijs and Hubl iodine solutions on fats and oils is fairly concordant ; but on rosin or resin acids it is very different.One sample of rosin gave a Hub1 value of 156.7 and a Wijs value of 250.6 at eighteen hours. The widely different results obtained by the two methods would suggest that chlorine compounds are formed and this seems to be borne out by the immediate change in the colour of the Wijs solution on coming into contact with the rosin whereas in the case of tallow acids no such change occurs. The authors therefore conclude that the iodine process as at present worked is of doubtful utility in determining the nature of the fatty matters in a mixture of these with resirL acids. F. H. L. Essential Oil of Chrysanthemum. G . Perrier. (Bzdl. soc. Chim. 1900 xxiii., 216 217.)-The green leaves of Chrysaizthemum japonicum or autumn chrysanthe-mum furnish on distillation with water a green essential oil.The yield (about 16 per cent.) varies with the different species of the plant the maximum amount being obtained just before the flowers begin to fall. The essential oil is a liquid of an oily consistency with an odour recalling that of peppermint and that of chamomile. It begins to boil at 160” C. and has a specific gravity of 0.932 at 15” C. and a refractive index of 1-4931 at 18” C. It is soluble in 10 volumes of 95 per cent. alcohol but is nearly insoluble in 70 per cent. alcohol. * These latter figures however can scarcely be considered to represent the constants of colophony acids for the unsaponifiable matter of the rosin except that “removed in [aqueous] solution or by volatilization in the process of drying,” was not extracted.The abstractor has usually found the proportion of unsaponifiable matter in the low-grade rosin ‘( B.C.” to be about 7 per cent.-F. H. L 216 THE ANALYST. When cooled to - 15" C. it deposits a small quantity of a solid amorphous substance, probably a paraffin ; at -24" C. it becomes viscid and solidifies when cooled in a mixture of ether and solid carbon dioxide. I t combines partially with sodium bisulphite is acid to litmus and has a Saponification value of 8-61. The alkaline salt formed in the saponification yields when treated with hydrochloric acid a solid substance with an odour of angelic acid. From a preliminary examination the author considers that chrysanthemum oil resembles the oil of Roman chamomile in composition.C. A. M. Properties of some Essential oils. Schimmel and Co.'s April Report. (Chem. Zed. 1900 xxiv. 304.)-Oil of Basil.-Two descriptions of this substance are now recognised. From the large-leaved variety of Ocymzcm basilicum known locally as Selasih Mekah between 0.18 and 0-32 per cent. of oil can be obtained by distillation, which has a specific gravity of 0.90 at 26" C. and a rotatory power of -30.5" to - 36" in a 200-millimetre tube. The oil contains from 30 to 40 per cent. by volume of eugenol. From its neutral constituents a body of agreeable odour boiling at 190" C., has been recovered and is now under investigation. The other variety of 0. basiliczim yields about 0.2 per cent. of oil smelling like fenneI with a specific gravity of 0.945 at 25" C.I t boils mostly between 214" and 218" C. and consists largely of methyl-chavicol. On treatment with alcoholic potash it gives anethol; and on oxidation, anisic acid. Oil of Iris.-J. C. Stead has succeeded in obtaining from 5 parts of the usual solid or buttery material 1 part of a golden-yellow oil with a fine odour of violets when highly diluted. It is soluble in all proportions in ether alcohol chloroform, petroleum spirit and benzene and yields a clear mixture with 8 volumes of 70 per cent. alcohol. I t is acid to litmus. = 0.9489 ; [a] = - 28.25". I t solidifies at - 5" C. I t decomposes on distillation at atmospheric pressure and contains no constituent separable by bisulphite ; but by treatment with alkali before and after acetylation is shown to contain free acids and some alcoholic bodies.Oil of Rosemary.-Recent investigations by Guerbet of pure santalol recovered from its phthalic acid compound throw doubt on the correctness of the hitherto accepted formula C1,H,,O. On hydrolysing acetylated santalol figures were obtained 'corresponding to a content of 103.5 per cent of santalyl acetate whence santalol must either have a smaller molecule (perhaps C15€1220) or it must be a mixture of two differently composed alcohols. Oil of Wartara.-This is a new product prepared by Schirnmel from Bombay Wartara seeds which closely resemble the fruit of Xanthoxyhm piperitzcnz R. C. and probably also belong to the Rzctacew. On distillation about 2 per cent. of an oil smelling like coriander was obtained specific gravity 0.8714 ; rotatory power, [a] = + 6" 31' ; saponification value 27-1 ; solubility 1 vol.in I vol. of 80 per cent. alcohol. By distillation at a pressure of 14 millimetres it was separated into six fractions of which the first boiled at 175" to 176" at atmospheric pressure and gave a large yield of a tetrabromide melting at 125" showing it to be almost pure pentene. The fractions 3 to 5 were rectified and finally an oil was recovered which exhibited the properties of d-linalol specific gravity 0.868 ; rotatory power + 14" 20' ; boiling-Its optical values are THE ANALYST. 217 point 78” at 14 millimetres. The identity of this oil with d-linalol which has hitherto been found only in oil of coriander was proved by its conversion into citral and into 1-terpineol etc.F. H. L. _. On Certain Methods for the Determination of Cellulose. C. Beck. (Zeit. f j i r Untersuch. der Nahr. amd Geizussmittel 1900 iii. 158-164.)-The methods studied by the author were Lebbin’s (Arc. Hyg. 1897 xxviii. 212) Konig’s (Zeit. fiip. Untersuch. der Nahy. m d Genzusnzittel 1898 i. 3-16 ; ANALYST 1898 xxiii. 47) and Henneberg’s. Lebbin’s method is briefly as follows 3 to 5 grammes of the substance are first boiled with 100 C.C. of water for half an hour; 50 C.C. of 20 per cent. hydrogen peroxide are then added and the boiling continued for twenty minutes, during which 15 C.C. of a 5 per cent. ammonia solution are added in small quantities at a time. This is followed by another boiling for twenty minutes after which the raw fibre is filtered off washed with hot water dried and weighed.Konig’s method has already been published in this journal (vide abstract cited above) The old method of Henneberg (boiling successively with dilute sulphuric acid and potash solution) was studied in conjunction with the two newer processes for the sake of comparison. I n all cases the amount of cellulose was arrived at by deducting the sum of the pentosans (determined by Tollens and Councler’s method) the nuclein (N by Kjeldahl x 6-25} and the ash from the raw fibre. The most concordant results were obtained with Henneberg’s method and the author considers that for establish-ing a comparison between the finer sorts of flour this method furnishes the most reliable data. Lebbin’s method yielded the least concordant results.In connection with this method the author tried the effect of removing as far as possible the starch and the albuminous bodies before boiling with the hydrogen peroxide. The results however were still unsatisfactory and are only interesting in so far as they show the unsuitability of hydrogen peroxide for the purpose even under conditions more favourable than obtain in the original method. The author does not consider Lebbin’s method of any value at all either scientific or practical. The results obtained by Kiinig’s method were also very discordant owing apparently to variations in the boiling-point of the liquid. It also seemed that some other substance must be left in the raw fibre in Konig’s method since the cellulose found in bran and flour by this method by deducting the nitrogenous substances pentosans and ash from the raw fibre was greater than that obtained by Henneberg’s method notwithstanding that the cellulose is less attacked in Henneberg’s method than it is in Kiinig’s.Remarks on the Foyegoinq Paper by J. Koniq.-Kiinig remarks that the discordant nature of the results obtained by Beck with his method was probably due to his instructions regarding temperature not having been accurately followed. The temperature should be maintained within the limits of 131” and 133” C. This can easily be done by using glycerin of 1.229-1-230 specific gravity working upon air-dried substances containing not more than 12 per cent. of water and reducing the flame of the burner as soon as the fluid commences to boil.The use of a digester, however is preferable to open boiling and in this case the temperature should be maintained at 137” C. for one hour. Beck’s opinion as regards the suitability of Henneberg’s method for discriminating between fine flours is directly contrary to Konig’s experience. He considers that Henneberg’s method is less reliable with fin 218 THE ANALYST. flour and rarely gives concordant results on account of the difliculty of filtration. Konig remarks further that his object as stated in his paper was to devise a method for separating as completely as possible the pentosans from the hexosans, and that no method yet proposed furnishes pure cellulose of the formula n(C6H,,05). H. H. B. S. Notes on the Estimation of Cellulose. C. Councler.(Chem. Zeit. 1900, xxiv. 368.)-The author discusses four methods which have been proposed for this determination (1) The Schulze-Henneberg process (2) H. Miiller's process and (3) that recommended by G. Lange (ANALYST 1895 xx. 283). Miiller's process is carried out by extracting the material with a mixture of alcohol and benzene and next with hot water; then removing from the residue certain incrusting substances'' by repeated alternate treatments with 0.4 per cent. bromine-water and 0.4 per cent. hot ammonia filtering and washing the mass between each stage of the operation. Muller claims that four such treatments with bromine and ammonia are sufficient to yield pure cellulose; but Councler always finds more sometimes twenty, alternations to be necessary.The method thus becomes exceedingly laborious and Councler has endeavoured to shorten it by (4) previously heating the sample with calcium bisulphite solution (8" Beaume) for four or eight hours at a temperature of 110" to 140" C. in a sealed tube and then proceeding as before. All these four processes show different results (3) and (4) giving the lowest but not identical figures; (3) is untrustworthy because no true solvent for cellulose having yet been discovered the substance dissolved by Lange's alkali and pre-cipitated by his strength of acid is not cellulose; (4) is incorrect because cellulose appears to be attacked by bisulphite at temperatures of 100" C. and upwards; (1) and (2) seem to give better results but are too complicated and tedious. An exact and simple method of estimating cellulose has therefore yet to be elaborated.F. H. L. On the Determination of Carbon and Hydrogen by Combustion in Oxygen, using Copper Oxide. C. F. Mabery and W. Fb. Clymer. (Jozmz. Amer. Chenz. Xoc. vol. xxii. [4] pp. 213-218.)-1n investigating the conditions necessary to insure accuracy in the combustion analysis of hydrocarbon oils the authors find that copper oxide is reliable when brought into a constant condition by blank trials. For the drying apparatus they recommend combustion-tubes 175 centimetres long bent at an angle of about 105" at 30 centimetres from one end one set being filled with broken glass and concentrated sulphuric acid the other with glass and 40 per cent. potassium hydroxide solution. Sulphuric acid forms the best absorbent for the water produced during combus-tion and when used in small quantity (2 to 3 c.c.) retains but a very slight proportion of carbon dioxide.The tube employed has st bulb for collecting the greater part of the condensed water; the front limb of the U-tube is 10 centimetres high and a lateral tube is attached for connection to the potash bulb. This drying-tube may be used for ten to twelve combustions before recharging with acid. For carbonic acid absorption the Geissler bulb is the most convenient apparatus THE ANALYST. 219 and no loss occurs provided the 33i per cent. potassium hydroxide be used for not more than four or five analyses. With the ordinary calcium chloride tube air may be safely passed at the rate of 500 C.C. per minute and the freshly-fused fine granular chloride may be used in a large number of analyses.The combustion-tubes require a long time to bring them and the connections into good working order-expulsion of volatile impurities from the copper oxide, moisture from the tube oxide and rubber stoppers etc. If the tube be filled with oxygen before inserting the substance and the rate of volatilization be carefully con-trolled any hydrocarbon may be burned in a 20-burner furnace. No advantage is gained by weighing the absorption-bulbs full of oxygen instead of air. c. s. The Elementary Analysis of Organic Substances containing Nitrogen. F. G. Benedict. (Amer. Clzem. J o z L ~ . vol. xxiii. [4] pp. 334-352.)-To secure the reduction of the copper without adding unknown amounts of carbon dioxide and water to the materials to be weighed the author recommends that such nitro-compounds as contain a deficiency of carbon and hydrogen in the molecule should be burned in admixture with a carbonaceous substance of known composition the resulting products being then in a position to react upon and reduce the oxides of nitrogen present.Naphthalene benzoic acid and sucrose are highly suitable but the first-named is diflicult to obtain pure whereas pure dry sucrose can be readily obtained. I t is generally desirable in charging the boat to leave a free space of about 1 centimetre at the front end which space is filled with the reducing agent (e.g., sucrose) the rest being sprinkled over the substance. A space of 1 centimetre is left between the front end of the boat and the asbestos plug in the combustion-tube.The spiral in the front end of the tube is heated first and then the copper oxide, before the reducing material in the boat is reached The gases evolved by the sucrose reduce part of the adjacent copper oxide; and the final charring of the sucrose leaves an excess of carbon to aid in reducing the nitro-group. The conditions are different with benzoic acid there being little or no carbon left though the copper oxide is reduced for a distance of several centinietres. I n calculating the results, allowance is made for the known weight of water and carbon dioxide formed by the reducing agents employed. An admixbure of three or four volumes of finely-powdered dry silica increases the regularity of combustion and appears to have a direct influence on the reduction of the oxides of nitrogen which under these circumstances are found in much smaller quantities in the products of combustion.c. s. A Colour Reaction given by the Products of the Digestion of Fibrin a,nd Albumin with Papayotin. V. Harlay. (JozLY?~. Pharnz. Chem. 1900 xi. 172-178.) -The products of the digestion of proteids with the juice of CariccL hastifolza were found by the author to give with tyrosinase the same coloration as that given by the products of peptic digestion (ANALYST xxiv. 272) but in a greater degree of purity. The green colour in the case of pepsin resembled that of chlorophyll whilst th 220 THE ANALYST. papayotin green had more of a blue shade. This was shown to be due to the presence of other colouring matters which accompanied the pepsin green and which on reduction with zinc and hydrochloric acid were destroyed first.I n both digestions the main colours had the same spectrum and reactions and were considered by the author to be identical. C. A. M. A Method of distinguishing Indigo from other Blue Dyes in Woven Fabrics. F. H. van Leent. (Zeit. anal. Chem. 1900 xxxix. 92-95.)-The threads of the fabric under examination are disintegrated into a loose wool and a portion covered with pure melted phenol in a test-tube which is then kept for an hour in a boiling water-bath with occasional agitation. The blue solution which is obtained when indigo is present is poured off from the fibres and the treatment with phenol repeated if required. The fibres are then washed two or three times with strong alcohol and after pressing and drying a pure white wool is left.Indigo red and another red colouring matter possibly originating from the indigo are simultaneously dissolved by the phenol. When the phenol solution is mixed with a large quantity of strong alcohol the greater part of the indigo blue is precipitated and the liquid shows the colour of the indigo red. If the fibres be boiled with the phenol they are strongly attacked by it which, however is not the case at the temperature of boiling water. Aniline and nitro-benzene extract hut little indigo from dyed wool at 100” C. and are therefore unsuitable solvents for the test. In experiments with wool dyed with other colouring matters the author has so far found that with the exception of indophenol indigo is the only dye dissolved by phenol under the above conditions.The result8s of his experiments are shown in the following table : Pure indigo . . . Indigo with sandal-wood . . . . Indigo and alizarin blue with chrome mordant - . Indigo and indophenol in mixed bath . . . < . . Brilliant sulphonazurine . . . . . . Indulin . . . . Indigo over alizarin . . Indigo sulphonic acid . . . . Alizarin indigo blue . . . . Alizarin cynnin . . . Anthracene blue . . . Logwood with mordant of alum, . . . chromium and antimony Colour completely extracted ; fibres white. Indigo removed; red colouring matter left on the fibres. Iudigo removed ; fibres blue. Iudigo removed ; fibres red. Much colour removed; fibres still blue.Only a little colour removed; fibres blue. Nothing removed ; fibres unchanged. A little removed ; fibres blue. Nothing removed ; fibres unchanged. Liquid coloured red ; fibres remain blue. Some red estracted ; fibres unchanged. Unchanged. Other dyes such as palatine scarlet cochineal and anthracite black also remained undissolved by the phenol. On testing a mixture of fibres dyed with pure indigo with anthracene blue and with indigo and sandal-wood only the indigo dissolved and under the microscope the different colourless blue and reddish brown fibres could be identified THE ANALYST. 221 The test is not so suitable for cotton as for woollen fabrics since indoin is dissolved from cotton by the phenol as readily as indigo. The author has not succeeded in quantitatively estimating the indigo by this method chiefly on account of the difficulty of separating the fibres from the phenol solution without loss.C. A. M. Notes on the Valuation of Tanning Materials. Paessler. (&?its. angew. Chem. 1900 318.)-The author holds that if the directions laid down in the '' Report of the First Congress of Leather-Trades Chemists " (H. Proctor and J. P. Parker) are followed exactly the results obtained on analysing samples of tanning materials will become quite satisfactorily uniform and accurate. He also calls attention to the following points It is necessary to take great care in selecting 8 small sarnple for analysis even when the material has already been sampled from bulk. Many tanning materials contain a large number of foreign substances of different specific gravities and so tend to separate into layers of different composition during agitation or transport.Especially with materials which are but imperfectly soluble in water, the particular grade of filter-paper employed is of considerable influence on the results. Schleicher and Schull's No. 602 '( Extra Hard " is the best ; in all cases the filtrate inust be perfectly clear for even the trace of suspended matter that passes a softer paper and renders the liquid only opalescent is taken up by the hide-powder and affects the figures of the analysis. The use of a hide-powder containing a certain proportion of filter-paper is distinctly advantageous ; the cellulose prevents the liquid from rising up the walls of the filtering vessel and also assists in the washing of the tanned hide-powder.Mehner and Stransky of Freiberg-i.-S. are now making a powder with 15 to 18 per cent of filter-paper (instead of the 35 per cent. advised by Cerych) which behaves admirably. The hide-powder is best packed so that the, filtrate passes at about 10 drops per minute; excessive tightness causes loss of tannins by dissolution of the soluble matters of the powder but the errors are not serious. I t is advisable and in special cases important that the temperature of the extract when being diluted to the desired volume and of the liquid during filtration, should be maintained at the normal point 17-5" C.; for the degree of solubility of some of the almost insoluble tanning constituents depends largely upon that temperature.F. H. L. The Detection and Estimation of certain Vegetable Substances commonly used to adulterate Sumach. (Stax. Sprzwzent. 4 g m ~ . 1900 xxxiii., 168-171.)-Sicilian sumach should consist of the dried and powdered leaves of Rhlls coYiaricL ; but from the author's experience it appears to be widely adulterated with the leaves of other plants containing tannin and notably with those of the Tamni-ix nfricaiaa and of the lentiscus (Yistacin leiztiscus). Of the methods proposed to detect these adulterants a microscopical examina-tion of the powder as recommended by Brizi requires long experience and is hence, practically unused whilst that of Spica (Gaxzetta 1897 354) does not solve the problem. The author's method is based on the fact that when finely-powdered sumach is G.Scarlata 222 THE ANALYST. allowed to fall upon glycerin (specific gravity 1-26} which is then brought to the boiling-point and left for an hour the sumach subsides completely and the super-natant glycerin assumes a greenish-yellow tint. If however the test be tried with finely-powdered lentiscus leaves the powder is left on the surface of the glycerin to which it imparts a wine-red colour ; whilst in the case of the tamarix leaves the powder remains in suspension and only falls after twenty-four hours. I n his experiments on the quantitative determination of lentiscus in sumach the author prepared a mixture containing 20 per cent. of the former. Five grammes of this mixture previously passed through a fine-rueshed sieve were introduced into a large test-tube containing 110 C.C.of glycerin (specific gravity 1.26); the liquid was heated to the boiling-point without shaking and boiled for a few moments until there was a complete emulsion. It was then left for twenty-four hours after which the supernatant glycerin together with the powder on its surface was removed by means of a pipette. The powder was collected on a weighed filter washed with water until free from glycerin dried in the water-oven and weighed. The results thus obtained varied from 0.65 to 0.70 gramme. The loss through solubility of the powder in the glycerin amounted in the mean of several determinations on 1 gramme of pure lentiscus to 30 per cent. and on adding this to the amount actually found, the results agreed well with the quantity taken.I t was not found possible to quantitatively estimate tamarix leaves in this way, but they could be identified. For this purpose 5 grammes of the sieved sample were introduced into the tube of glycerin which was then boiled as described above and allowed to stand for two hours. If the supernatant glycerin was then clear and of a yellowish-green colour the sumach was regarded as pure. If however after twenty-four hours part of the powder remained on the surface while the glycerin was clear and of a wine-red colour the presence of lentiscus leaves was in the author's experience certain. Finally when taniaris leaves were the adulterant part of the powder remained after two hours i n suspension in the glycerin which had the same wine-red colour as in the case of lentiscus. After twenty-four hours the suspended powder completely subsided. Here too the glycerin is coloured wine-red. C. A. M. I N O R G A N I C A N A L Y S I S . Direct Determination of Carbon in Metallic Alloys. H. Brearley. (Che??~. iNews vol. lxxxi. pp. 91 92.)-Samples of various alloys were heated for one hour in a Bunsen furnace the porcelain tubes being supported in asbestos arches thus enabling a higher temperature to be maintained than usual with combustion tubes. The results showed the method to be applicable to metallic tungsten ferro-tungsten ferro-silicon 12 per cent. silicon-spiegel ferro-silico-molybdenum and 20 per' cent. spiegel, though the last-named could not he completely oxidized. On the other hand, metallic molybdenum volatilizes leaving only impurities like SiO, W03 etc. ; tungsten-nickel alloy is imperfectly oxidized and ferro-manganese ferro-chromium, chromium nickel and metallic chromium cannot be oxidized without some other oxidizing reagent. Ferromanganese is oxidized completely in presence of oxides inert towards chromium alloys e.g. zinc oxide. c. s

ISSN:0003-2654    

DOI:10.1039/AN9002500207

出版商:RSC    

年代:1900

数据来源: RSC

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THE ANALYST. 223 APPARATUS. New Device f o r drying Crystallized Salts. (C1iem. Nc?os., vol. lxxxi., p. 91.)--The apparatus consists of a large porous cup, B B, to contain the salt to be dried, with a hole in the bottom to take a good-sized 8 cork, the mouth being also closed with a cork. Glass tubing is fitted centrally through both corks, and, the whole being placed in a frame or box F F, the tube A is con- nected with an aspirator, whilst the other tube is connected with the drying tube D, with or without the intermediate tube C, which can be heated t.0 any desired temperature when hot air is required. The cup may be slowly rotated from time to time to expose a fresh surface of the salt to the a,ir current. F. H. Getman. C. s. An Improved Wash-Bottle with Bunsen Valve. 0.Gamber. (Clienz. Zeit., 1900, xxiv., 395.)-When an ordinary wash-bottle is fitted with a Bunsen valve, it is impossible to arrest the stream of water suddenly without loosening the cork of the flask, unless the exit tube is provided with a length of rubber which can be pinched with a clip or with the fingers. The annexed sketch represents an improvement that brings the current of liquid under more immediate control. CL is a bent piece of glass tube, carrying at its outside end a short length of rubber, b, the normal diameter of which is about one-half that of the glass. Within the glass tube slides easily a conical piece of rod (shaded in the diagram), which has a maximum diameter less than that of the glass, but greater than that of the rubber. When there is an excess of pressure in the wash-bottle, the rod is forced outwards till it makes a joint against the rubber tube; but if the finger give a slight lifting movement to the ball at the end, the rod slips upwards, the joint is broken, the pressure relieved, and the stream of water stops. F. H. L. ~ - _ _ _ _ _ _ _ ~- _ _ ~ - Aluminium Plates for Laboratory Purposes. Fritsch and Venat or. (Chem. Zcit., 1900, xxiv., 286.)-The authors recommend sheets of aluminium 3 or 4 milli- metres thick as substitutes for the ordinary wire gauze or sand bath. They have employed such a plate for five years in a fume cupboard, and it is still in perfect con- dition. The efficiency of the gas-burner is much greater than with a sand bath, while dust and breakage of the gauze are avoided. When evaporating liquids to dryness, a thin sheet of asbestos should be laid over the metal. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN9002500223

出版商:RSC    

年代:1900

数据来源: RSC

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224 THE ANALYST. INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND. THE following is a list of the names of the candidates who passed the examination of the Institute of Chemistry held in July, 1900 : INTERMEDIATE EXAMINATION.-Brown, J. A., University College, Nottingham. Chapman, E. M., Pharmaceutical Society’s Laboratories, and King’s College, London. Cunliffe, F., Owens College, Manchester. Dewhirst, J. A,, Yorkshire College, Leeds, and Pharmaceutical Society’s Laboratories. Dick, W. D., King’s College, London. Ellis, A. W., Mason University College, Birmingham. Gray, &4., Glasgow and West of Scotland Technical College. Lowson, W., Yorkshire College, Leeds. Lumsden, W. W., Glasgow and West of Scotland Technical College. Mclellan, B. G., Glasgow and West of Scotland Technical College.Nuttall, W. H., Gniversity College, Nottingham. Partridge, W., Finsbury Technical College, London. Robert - gon, A. J., University College, Dundee, and under R. R. Tatlock, Esq., F.I.C. ’Tainsh, P. W., Glasgow and West of Scotland Technical College. Tebb, W. S., ?AT.A., B1.D. (Cantab.), Cambridge University and King’s College, London. Thorburn, J., Glasgow and West of Scotland Technical College. Watson, F. W., Glasgow and West of Scotland Technical College. GENERAL PRACTICAL EX.~MIN~TION.-SC~~~, A. ,* Glasgow University, Glasgow and West of Scotland Technical College, and under R. R. Tatlock, Esq., F.I.C. FINAL A.I.C. EXAMINATIOX.-I~Z Mimral Chemistry : Baguley, A., B. Sc. (Wales), University College, Bangor. Davidson, A., Glasgow and West of Scotland Technical College.Hartley, T. ,* Yorkshire College, Leeds. Kinnersley, H. W., Merchant Venturers’ Technical College, Bristol, King’s College, London, and under E. H. Cook, Esq., D.Sc. (Lond.), F.I.C. Reinherz, O., B.A. (Cantab.), Trinity College, Cambridge. In Metalluryical Chemistry : Levy, A. G. , Finsbury Technical College, London. In Physical Chemistry : Pope, T. H., A.C.G. I., City and Guilds of London Institute, Central Institution, and Finsbury Technical College, London. In Organic Chemistry .- Billows, F. G. H., A.C.G.I., City and Guilds of London Institute, Central Institution, and Finsbury Technical College, London. Iu the Analysis of Food awl Dmgs, including an Exanzinatioiz in Them- p e h c s , Pharmacology and Microscopy : Aston, S., University College, London. Booth, N. P., Mason University College, Birmingham. Glass, T. W.,* B.Sc. (Lond.), Pharmaceutical Society’s Laboratories, and under Messrs. T. H. Redwood and A. J. de Hailes, FF.1.C. Jollyman, W. H., Finsbury Technical College. Platt, W. N.,* B. Sc. (Lond.), A.R.C.Sc. (Lond.), Royal College of Science, London. Woodhead, S. A. ,* B. Sc. (Dun.), Durham College of Science, Newcastle-on-Tyne. The examiners in chemistry were Dr. Bernard Dyer, D.Sc. (Lond.), F.I.C., and Dr. W. Palmer Wynne, D.Sc. (Lond.), F.R.S., F.I.C. The examiner in therapeutics, pharmacology and microscopy was Dr. Thomas Stevenson, M.D. (Lond.), F.R.C.B., v.-P.I.C. Jenkins, J. E., King’s College, London. Richmond, S. O., Finsbury Technical College, London. Morgan, J. tJ.,* of Wednesbury. + For the Fellowship (W. I. C. ).

ISSN:0003-2654    

DOI:10.1039/AN9002500224

出版商:RSC    

年代:1900

数据来源: RSC