THE ANALYST. 235 ORGANIC ANALYSIS. The Determination of Methyl Alcohol in Formalin. 0. Blank and H. Finkenbeiner. (Berichte, 1906, xxxix., 1326, 1327.)-Nethyl alcohol is an ordinary constituent of the commercial (40 per cent.) solutions of formaldehyde, an addition of IS to 18 per cent. being made to prevent the liquid becoming permanently turbid when exposed to cold. The author bases a method for its determination on the amount of oxygen consumed when a weighed quantity of bhe formalin is oxidized by means of chromic acid and sulphuric acid- H.COH + 0, = CO, + H,O CH,.OH + 3 0 = GO2 + 2H,O. Qne gram of the sample is introduced into a mixture of 50 C.C. of chromic acid solution with 20 C.C. of skrong sulphuric acid, and the whole allowed to stand for about twelve hours a t the ordinary temperature, or about one to one and a half hours if the liquid be heated cautiously, care being taken not to let it evaporate below a third of its volume.The liquid is then made up to a litre and 50 C.C. withdrawn, and, after the addition of a crystal of potassium iodide, titrated with a sodium thiosulphate solution. From the result the total amount of oxygen consumed can be calculated, and, the amount of formaldehyde in the original solution being known, the percentage of inethyl alcohol can be obtained indirectly. In a test experiment described the result obtained was identical with the amount (7.65 per cent.) of methyl alcohol added t o a 20 per cent. solution of formaldehyde. c. A!!. 31. New Method for the Determination of Acetone. S. J. M.Auld. ( J o z ~ r ? ~ . S'oc. C'lzem. I n d . , 1906, xxv., 100, 101.)-The acetone in wood spirit, crude acetone, etc., is converted into bromoforrn, the latter decomposed with alcoholic potash, and236 THE ANALYST, the residual potassium bromide titrated with silver nitrate solution, the hydrolysis being represented by the equation- 3CHBr, + 9KOH + C,H,OH = 3CO + C,H4 + 9KBr + 7H,O. A quantity of the solution containing 0.1 to 0.2 gram of acetone is pipetted into a 500 C.C. round-bottom flask, diluted with a little water, and mixed with 20 to 30 C.C. of a 10 per cent. potash solution. The flask is attached to a long reflux condenser, and is fitted with a dropping funnel containing a solution of 200 grams of Br and 250 grams of KBr per litre. This solution is allowed to flow into the mixture until it has acquired a faint yellow tinge, the flask heated on the water-bath at about 70" C.for half an hour, and more bromine solution added drop by drop until the slight coloration is permanent, any excess being removed by boiling with a little more potash. The mixture is then distilled until the distillate is free from bromoform, water being added to the contents of the flask if necessary, and the condenser rinsed with a little alcohol. Distillate and washings are mixed with 50 C.C. of alcohol and sufficient solid caustic potash to make an spproxirnately 10 per cent. solution, and the mixture heated on the water-bath under a reflux condenser until the bromoform is completely decomposed, which occupies about three-quarters of an hour.After evaporating to smaller bulk, if necessary, the liquid is cooled, neutralized with dilute nitric acid, diluted to 500 c.c., and an aliquot part titrated with TG silver nitrate, using K,CrO, as indicator ; 240 parts of bromine correspond to 58 parts of acetone. Pure bromine must be employed, as crude bromine frequently contains bromoform. W. H. S. The Determination of Acetone. A. Jolles. (Berichte, 1906, xxxix., 1306, 1307.)-The method is based upon the fact that acetone combines with sodium bisulphite (1 molecule : 1 molecule), forming the sodium salt of a sulphonic acid siailar to that obtained with furfural (ANALYST, xxxi., 116)- The standard bisulphite solution is added to the acetone solution in a quantity three or four times greater than the theoretical amount, and the excess is titrated with standard iodine solution after the mixture has been allowed to stand for not less than thirty hours.A blank determination with the sodium bisulphite solution should be made simultaneously to obtain the correction for any changes it may undergo during the experiment. C. A. M. Experiments made with Dettmarsch's Apparatus for Testing Oils. Richard Kissling. (Cherm. Zeit., 1906, xxx., 152.)-The author has made over 500 tests on the Dettmarsch apparatus (shown in the figure) for testing the lubricating power of oils. The apparatus consists essentially in two heavy fly-wheels, a and b, connected by a shaft revolving in a journal between them, to which the oil to be tested is fed from the reservoir (h, situated just under the right-hand bearing), where it is heated electrically.The fly-wheels are driven by the motor, c, and canTHE ANALYST. 23 7 be instantaneously disconnected from the latter by releasing a spring, d. The method of working is to impart a certain measured velocity to the fly-wheels, then to release the spring, and to measure the time taken for the revolution to stop entirely. From these data a “coeflicient of friction ” gives results in good agreement with is calculated. Although the apparatus often tb.e viscosity determinations and the results t obtained in practice, the author has obtained so many totally inexplicable results with it (apparently attributed by him to the presence of an imperfection in the apparatus) that he condemns it entirely. E e believes the only way to determine the lubricating power of an oil to be to test it in situ in the machine for which it is to be used.A. G. L. Preparation of Aldehyde-free Ethyl Alcohol for Oil and Fat Analyses. F. L. Dunlap. (Jozwuz. Amer. Chem, Xoc., 1906, xxviii., 395-398.)-Alcohol yielding a colourless potash solution may be obtained by adding to 1 litre in a glass- stoppered cylinder a solution of 1.5 grams of silver nitrate in 3 C.C. of water, mixing thoroughly, then pouring in slowly, and without shaking, a solution of 3 grams of potash in 10 to 15 C.C. alcohol. The finely-divided silver oxide precipitated gradually distributes itself through the alcohol, and after standing overnight completely settles, when the clear, supernatant liquid is filtered or siphoned off and distilled.W. H. S. On the ‘‘ Milkiness” of Paraffin Wax. H. Mittler and R. Lichtenstern. (Chem. Bev. Fett. ZL. Harx-I?zd., 1906, xiii., 104, 105.)-Transparent paraf5n wax fetches a higher price than ‘( milky ” wax, and the greater value of the clear products j s due to more than their better appearance. Neustadtl concluded that ‘‘ milkiness ” was caused by differences in the melting-points of the different constituents of the paraffin ; but the authors contest this, and point out that transparent paraffins with238 THE ANALYST. melting-points as far apart as 57" and 42' C. can be mixed together without rendering the product opaque, though in some instances a bluish shade may be produced. They attribute the '' milkiness " to the presence of paraffin oil, and have isolated that oil from (I milky " paraffin by extraction with a mixture of alcohol and ether, and have rendered transparent paraffins " spotted " or milky " by adding oil in the proportion of 0.5 to 3 per cent.The addition of smaller quantities up to 0.3 per cent. has little or no effect upon the transparency. C. A. M. Constants of Carnauba Wax. L. G. Radcliffe. (Joz~m. SOC. Clzem. Itzd., 1906, sxv., 158.)-The following figures have been obtained with a sample of Gear& wax : Melting-point (in capillary tube), 84" C. ; acid value, 2.9 ; acid value deter- mined by dissolving 3 grams in 120 C.C. of boiling amyl alcohol, 5 ; saponification value (5 grams dissolved in 60 C.C. amyl alcohol, and boiled for six hours with 50 C.C. alcoholic potash containing 60 grams of potash per litre), 88.3 ; ester value, 854 ; iodine value, 13.17.The bleached wax melted at 61", and had an acid value in amyl alcohol solution of 0.56. W. H. S. On the Proportions of Pentosan and Methylpentosan in Plant Products. John Sebelien. (Clzem. Zeit., 1906, xxx., 401.)-P. Sollied has continued the work done by the author and others to show that in the great majority of cases the amount of methylpentosan occurring in plants is considerably less than that of the pentosan also present. Sollied's results are given in the following table, Tollens and Ellett's method (Bey., 1905, 492) having been used : Oak-wood, fifteen-year-old tree Oak-bark, eighteen-year-old tree Cedar-wood ... ... ... Fir-wood ... ... ... ... Beech-wood ... ... ...Ash-wood ... ... ... ... Fucus vesiculosus ... ... Ditto, younger ... ... ... Ditto, younger branches ... Hay ... ... ... ... Ascophyllum nodosum ... ... Rye-bran ... ... ... ... Rape-seed cake ... ... ... Carrots (dry substance) ... ... Kohlrube (ditto) ... ... ... Oats ... ... ... ... Linseed cake ... ... ... Cotton-seed cake.. . ... ... ... ... ... ... .*. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... Methylpentosan, Per Cent. 2.26 2.31 2.08 2.54 2 90 4.70 2.68 2-95 2.13 3.16 3.47 1.75 1.09 1.72 2.62 1.72 2.59 2.93 Pentosan, Per Cent. 19-06 18-60 14.21 12.85 12.36 10.03 23.59 17.24 17.43 6.32 8-46 20.93 12.76 6.25 9.73 6.23 8-43 6.67 A. G. L.THE ANALYST. 239 Linaloe Oil. W. Naumann. (Chemist and Druggist, 1906, lxviii., 619.)-The following results were obtained on the analysis of three samples of oil shipped direct from Mexico and guaranteed by the shippers to be pure oils : Specific gravity at 15" C.... ... Rotation in 100 mm. tube ... Refractive index at 20" C. . . . Esters ... ... ... ... Linalol ... ... ,, 195" C. ... ... 7 , ,, 200" c. ... ... ,, 205" C. ... ... ... ... Distilling beiow 190°C. . .. ... ,? ? S No. 1. 0-8785 1.4635 -8" 30' 4.3% 66% 7% 25% 45% none No. 2. 0*8800 14633 4.7% 68% none 570 350,; 40% - 1 2 O No. 3. These results are similar to those obtained by Parry and Bennett (ANALYST, 1906, 20l), and accordingly the above oils belong to the best class now obtainable. w. P. s. On the Chemical Examination of Kerosine. K. Charitschkow. (Westizik shirozo., vii., 14 ; through C'hem.Zeit., 1906, xxx. [Rep], 142.)-Dehnstedt and Geisler have recently shown the presence of neutral sulphuric esters in various petroleum oils imported at Hamburg. The author now shows that similar esters are sometimes present in Russian petroleum, the quantity varying inversely with the amount of acid used in the purification of the oil. The esters may be recognised by treating the oil with aniline, aniline sulphate being insoluble in kerosine. On burning oil containing sulphuric esters, sulphurous and sulphuric acids are formed and the lamp- wick is charred. A simple method of determining sulphur in petroleum consists in distilling it over potassium, potassium sulphide being formed and determined in the usual manner. The quantity of unsaturated hydrocarbons present in kerosine should always be determined, as they yield a flame of unpleasant colour.A. G. L. Collaborative Work on Tannin Analysis. F. H. Small. (Joumz. XOC. Clzenz. Ind., 1906, xxv., 296-298.)-The American Leather Chemists' Association have formulated the following methods for the estimation of tannin in raw materials and analysis of the tannin solutions obtained therefrom. The material is ground to a specified fineness, and the tannin extracted in a copper Soxhlet apparatus so constructed that the extractive is removed from the action of heat, as prolonged boiling of the liquor converts part of the tannin into some compound not tannin, probably gailic acid. The analysis of the tannin solution is conducted on a solution containing 0.35 to 0.45 gram of tannin per 100 C.C.The residues obtained from the evaporation of 100 C.C. each of the solution before and after filtration give the amounts of total and of soluble solids respectively. The tannin is removed from another portion of the solution by treatment with hide-powder, which is then filtered off, and the clear240 THE ANALYST+ filtrate evaporated to dryness, the residue being the soluble non-tannins. By deduct- ing these from the total soluble matter the proportion of tannin is readily obtained. The hide-powder employed is first treated with a dilute solution of chrome alum, washed free from uncombined salts, excess of water squeezed out, and the moist powder added to the tannin solution, a correction being made for the water added with the hide-powder.Dificulties have arisen owing to failure to obtain clear filtrates, and to the retention of part of the tannin by the filter-paper, but by following prescribed conditions concordant results are obtainable. To avoid decom- position during evaporation and drying of the residues, a special copper steam-bath has been devised, with a solid top on which the dishes rest, and fitted with a steam- jacketed cover provided with openings for ventilation. W. H. s. Analysis of Ebonite Articles. R. Thal. (Chewz. Zeit., 1906, XXX., 499.)-As supplied to the Russian army medical service, ebonite cases for instruments and bottles must fulfil the following requirements : The ebonite must be made from best Para rubber and sulphur.The quantity of the latter may vary from 27 to 30 per cent., but should preferably be 29 per cent. The vulcanization must be even throughout, and the ebonite must be free from surrogates. The amount of ash must not exceed 0.60 per cent. On warming the ebonite with fuming nitric acid, a clear or nearly clear solution should be obtained. The material should be black, capable of being polished, and be free from cracks, indentations, porous or coloured spots, etc. ; it must be sufficiently hard, and yet not too brittle to be worked by tools. The cases must not break or crack on allowing them to fall by their own weight when empty on to a stone floor, OF on knocking them together. The analysis of ebonite is carried out by the methods usual for rubber. Moisture may be determined by drying for two hours at 100" to 105" C.; longer drying results in oxidation of the material. For the test with fuming nitric acid, 0.5 gram of the ebonite in small pieces is gradually added to 20 C.C. of the acid, and the whole is warmed until nitrous fumes are driven off. A turbid solution indicates an amount of ash greater than 0.6 per cent. I n testing for surrogate, a correction must be made €or the weight lost by the filter-paper on treatment with 8 per cent. alcoholic caustic soda. For accurate work corrections must also be made for the amount of sulphur extracted from, and the quantity of soda, retained by, the dried residue. The author has previously found this to be 5.5 per cent. A. G. L. Grading of Glues and Gelatines. J. Alexander. (Joz~riz.Xoc. Chew. I ~ z d . , 1936, xxv., 158-161.)-The author recommends the determination of the reaction to litmus, viscosity, grease, foam, set," jelly strength, adhesive strength (under actual working conditions), and keeping properties. The viscosity is measured by noting the time of efflux at 80" C. from a 45 C.C. pipette of solutionsicontaining 25 grams of glue in 100 C.C. of water. The effluent tube is 7 cm. long, and has external and internal diameters of 9 and 6 mm. respectively, the smal1est:dianieter of the outlet being about 1.5 mm. The length of the bulb is 9.5 cm., and its outside diameter 3 em. The amount of grease is approximately proportional to the spots appearing when the glue solution is painted on white paper with a little aniline or dry colour.THE ANALYST.245. Foam is estimated comparatively by agitating with a rod or mechanical agitator, and " set " is the speed with which the jelly hardens. Jelly strength is well measured by pressure with the finger-tips; but a special instrument, more reliable than the shot test, has been devised for the purpose, consisting of a brass cylindrical vessel supported like a gas-tank by four vertical rods, against which it slides with almost frictionless roller-bearings. This rests on a truncated cone of jelly, and shot are poured in until a definite expression of jelly is observed, two vertical brass uprights 3.5 cm. high connected with an electric-bell circuit being placed beneath the CUP, SO that when this reaches their level the bell rings. Keeping properties are observed by exposing the uncovered glue solutions for some days at room temperature.arbitrary series of standards has been devised, based upon the viscosities, sixteen nearly equidistant grades having values assigned of 10 to 160, 10 points being allowed bdmeen each grade. The grades specially adapted for particular purposes are mentioned. W. H. S. Conditions affecting the Foaming and Consistency of Glues. So R. Trotman and J. E. Hackford. (JOWL. XOC. Chem. I d , 1906, XXV., 104-107.)- Foaming of glue is increased by overboiling, by prolonged boiling with alkalies, and by the presence of peptones, of soda or lime, of soap beyond a certain limit, of carbolic acid, and of suspended matter. From the influence of the last-named, loaded glues, such as Russian, may be expected to give considerable foam.The amount of foam is reduced by rise of temperature, by the addition of lubricating, bone, Or cod oil, or of hydrochloric, sulphuric, acetic, salicylic, or oleic acid. The mineral constituents of water used in glue-making would not affect the quality of the resulting glue. The consistency of glue is not injured by small quantities of peptone SO long as they do not replace albumose nitrogen, but is seriously reduced by alkalies and acids, though in a less degree by small quantities of carbolic or boric acid, A small amount of soda or potash soap does not diminish the consistency. The foaming has been measured by means of a graduated tube about 70 ern. long, and of such diameter that each division is 1 cm. in length and has a capacity of I C.C.This is half filled with a 10 per cent. solution of the glue, placed in a water-jacket at 60" C., and after allowing the glue solution to attain this temperature, withdrawn, and the level of the solution adjusted to zero. The tube is then corked and shaken vigorously for one minute, replaced in the water-jacket, and the height of the foam read off. Consistency has been determined by noting the time taken by spheres to fall through a column of the given glue solution. H. J. Watson (ibid., 1906, XXV., 209-211), from independent experiments on the same lines, concludes that foaming is not materially increased by the presence of free alkali or acid, except sulphurous acid. Mucins increase the foam, and zinc sulphate lengthens the time it takes to die away, but heat appears to be the all-important factor in producing foaming glue, probably due to hydrolysis of the gelatin to gelatone.By reducing the period under heat to the shortest possible, practically foam-free glue should be obtained. This author measures the foam by shaking 50 C.C. of a 10 per cent. solution of the glue at about 50" C. in a stoppered graduated cylinder 2.5 cm. in diameter, and reading the height of the top of the foam as soon as the height of the solution reaches 45 C.C. SV. H. S.242 THE ANALYST, The Determination of Urea. B. Glassmann. (Berichte, 1906, xxxix. , 705-710.-The following modification of Liebig’s and Pfliiger’s methods is claimed to give very accurate results, and to be more easily applied than any other method.The urea is precipitated from the solution, which has been neutralized with sodium carbonate, by means of a known excess of standard solution of mercuric nitrate, the precipitate filtered off, the filtrate acidified with nitric acid, and the excess of mercury determined by titration with & ammonium thiocyanate solutiorr, iron ammonium sulphate being used as indicator. From the amount of mercury that has been taken up the urea is calculated by means of the equation- 2CON2H, + 4Hg(NO,), + 4H,O = [2CO(NH,), + Hg(NO,), + 3HgOJ + 6HN0,. The conditions for the determination of the urea in urine by this method are the same as those required in Liebig’s original method--viz. : (1) The urine must not contain more than traces of albumin, which otherwise must be precipitated with acetic acid. (3) It must not contain leucine or tyrosine. (4) I t must not contain abnormal amounts of alkali chlorides, bromides, or iodides, or of benzoic, salicylic, or hippuric acids. (5) If too darkly coloured it should be treated with animal charcoal. (2) I t must not be in full alkaline fermentation. C. A. M. Simplified Ultimate Analysis for Technical Purposes-11. M. Dennstedt. (Zeits. a.lzgew. Chenz., 1906, xix., 517 ; cf. ANALYST, xxx., 135, 348, and this vol., 122.)-The author has given up the use of platinized quartz, which occasionally scratches the combustion- tube, and now uses rolled-up pieces of platinum foil, or, better, platinum- foil “stars” (Fig. l j , weighing 1 or 2 grams, which may For the introduction of the double current FIG. 1. be obtained from Hereaus, of Hanau. of oxygen, the arrangement shown in Fig. 2 is recommended, as it very seldom requires renewal. A. G. L.