242 THE ANALYST. ORGANIC ANALYSIS. The Detection and Estimation of Small Amounts of Benzene in Alcohol. D. Holde and G. Winterfeld. (Chem. Zeit., 1908, 32, 313.)-The method is based Apon the fact that on distillation the whole of the benzene passes over in the first 10 per cent. of the distillate, and appears as an oily layer floating on the surface. One hundred C.C. of the alcohol under examination are diluted with sufficient water to bring the alcoholie strength to 24.7 per cent. by weight, the mixture distilled, and the first 10 C.C. of the distillate collected in a flask cooled in ice-water. On diluting this distillate with 18 to 20 C.C. of water, and transferring it to a measuring cylinder or a burette, the proportion of separated benzene may be read directly. The amount of benzene remaining dissolved in the turbid lower layer amounts to about 0.3 per cent.by volume, and remains practically constant whether the original quantity of benzene be 0.5 or 5 per cent. C. A. 11. Estimation of the Degree of Bleaching of Cellulose. C. G. Schwalbe. (FtirbeY-Zcit., 1908, 19, 33 ; Chem. Zeit. B e p , 1908, 32, 204.)-A normally bleaehed cotton should show no reducing action when boiled with Fehling's solution ; but faulty or excessive treatment with the bleaching chemicals may give rise to the production of oxycellulose or hydrocellulose, both of which reduce Fehling's solution. For the estimation of the cupric reducing power of any cellulose, two portions of 3 grams each of the sample are weighed out. One serves for the estimation of the moisture by drying at 100" to 105" C.for four hours, whilst the other is suitably disintegrated and moistened with 150 C.C. of boiling water. One hundred C.C. of Fehling's solution are heated to boiling and added to the moist cellulose, the vessel being rinsed with 50 C.C. of hot water. The mixture is heated under a reflux condenser for exactly fifteen minutes after full ebullition is reached. The mass is then drained on a, filter by means of a pump, and washed with boiling water until no more copper is dissolved. The cake of cellulose is then heated with about 30 C.C. of 6.5 per cent. nitric acid, and sufficient water to make a paste. The liquid is filtered off, and the residue washed with boiling water ; the filtrate is evaporated to a, small bulk, and the copper is determined electrolytically.Tht? weight of the metallic copper, expressed as per cent. of the cellulose dry substance, is called the '' copper value '' of the sample. Since mercerised cotton absorbs cupric oxide, a correction must be made for the copper deposited in this form. This is determined by a,THE ANALYST. 243 separate treatment with Fehling's solution, the cupric oxide being extracted with acetic acid instead of nitric acid. J. F. B. Manila and Pontianak Copals. C. Cofllgnier. (Bull. SOC. Chim., 1908 [4], 3, 453-459.)-The following results were obtained in the examination of commercial samples : Specific gravity . . . Melting-point . . . Acid value ... Saponification value Insoluble in boiling : Ethyl alcohol ... Methyl alcohol ... Amyl alcohol .... Ether ... ... Chloroform . . . Benzene ... ... Acetone ... ... Turpentine oil . . . Benzaldehyde . . . Aniline ... ... Amyl acetate Carbon tetrachloyide ... ... ... ... ... ... ... ... ... ... ... . . . ... ... ... ..I Manila (Hard). 1.065 at 17' C. 190" c. (soft at 80" C.) 72-80 87.0 Per Cent. 55.90 64.60 Soluble 58.50 36.70 63.90 52.0 73-20 1-10 Soluble 69% Manila (Soft). 1-060 at 1 7 O C. 120" c. (soft at 45O C.) 145.2 185.1 Per Cent. Soluble 7-30 Soluble 28-70 52-40 57.90 Soluble 64.10 1.70 Soluble Pon tiaiiak. 1.037 at 16" C. 135' C. (soft at 55" C.) 134.3 186.5 Per Cent. Soluble 13.50 Soluble 46.0 50.3 63.0 Soluble 66.40 Soluble Pontianak copal, which is a product of Borneo, has only been in use a few years. I t has an aromatic odour, recalling that of eleniic resin, and varies in colour from pale yellow to reddish-brown.I t closely resembles soft Manila copal in its general physical and chemical characteristics. C. A. M. Chrysalis Oil. M. Tsujimoto. (Jozinz. CoZZ. Eizgiizeering, Imp University, Tokyo, 1908, 4, 63-74.)-Chrysalis waste is now extensively used as a, source of oil for soap-making in the silk-producing districts of Japan. A sample of the material examined by the author contained 5-48 per cent. of moisture, 26.26 per cent. of oil, and 3-77 per cent. of mineral matter. The oil was a yellowish-red liquid, of un- pleasant odour. It solidified at 0" C., and gave the following analytical values: Specific gravity at 15.5" C., 0,9280 ; acid value, 18.68 ; saponification value, 194.12 ; iodine value (Wijs), 131-96 ; Hehner value, 94.5 ; Reichert-Meissl value, 3.38 ; true rtcetyl value, 19.72 ; refractive index at 20" C., 1-4757.Fatty Acids .- Specific gravity at 100°/15*50 C., 0.8513 ; melting-point, 36.5" C. ; solidification point, 27" to 289 C. ; neutralisation value, 199.34; mean molecular weight, 28143 ; iodine value, 135.83; unsaturated acids (with iodine value, 178.73)) 75 per cent.; and melting-point of saturated acids, 57" C. (cf. Lewkowitsch, ANALYST, 1907, 32, 53).244 THE ANALYST. The oil contained 9.42 per cent. of glycerin, and 1.63 per cent. of unsaponifiable matter, consisting principally of phytosterol (melting-point, 143.5' C.), and not cholesterol, as in the sample examined by Lewkowitsch (Zoc. c2.t.). The fatty acids yielded hexabromide corresponding to 4.38 per cent, of linolenic acid.No linolic tetrabromide was obtained, but isomerides of linolic acid were apparently present. The solid fatty acids contained palmitic acid, but no stearic acid was found. c. -4. &I. The Japanese Dyewood '' Doss." E. Ito. (Joimt. CoZZ. Eizgineeriiig, Imp. Univeysity, Tokyo, 1908, 4, 57-62 )-The bark and extract of the evergreen tree " d o s ~ ~ ~ (Ilcz Merteizsii, Naxim) is used as a substitute for myrica bark in dyeing. The author has isolated from it a new dyestuff, dossetiit, C15HyOj, which crystallises in yellow needles, and melts at 271" to 272" C. With alumina mordant it gives a dull yellow colour, with tin a bright yellow, and with iron an olive colour. C. A. M. Japanese Lacquer. K. Miyama. (Jour?b.CoZZ. Engineering, Imp. Uizi- versity, Tokpo, 1908, 4, 89-110.)-The milky juice (umshi) .frob the Japanese lacquer-tree, Rhus vernicifera, turns brown when heated or exposed to light, and is then mixed with pigments, oils, etc., to form the lacquer. The crude liquid contains as its main constituent a polyhydric phenol, C3+Hj004, termed urushiol by the author. I n very dilute solution this gives a green coloration with ferric chloride, changing to red on the addition of sodium carbonate. I t yields a green precipitate with barium hydroxide, and gives a silver mirror in the cold with tlmmoniacal silver nitrate solution. The quality of a lacquer depends largely upon the proportion of urushiol it contains, whilst the greater the quantity of gum the poorer the quality.Samples drawn from the same tree at different periods varied greatly in composition-e.g. , moisture, 17.81 to 27.62; urushiol, 64.14 to 77.63 ; gum, 2.62 to 7-57; and nitro- genous substances, 1.78 to 2.47 per cent. Lacquers imported from China and India, contained more moisture, less urushiol (36-88 per cent. in inferior Chinese, and 26.39 per cent. in medium Indian), and more gum (23.5 and 37.78 per cent. reapectively). The presence of an enzyme causes the lacquer to dry at low tempera- tures. At 70" to 80" C. the drying process is suspended, but at temperatures above 100" C. drying takes place without enzymic action, and the urushiol itself, which does not dry at the ordinary temperature, then also dries readily. I n the valuation of a lacquer, the durability, transparency, lustre, and smoothness of its dried film, and the duration of drying and viscosity of the substance itself, are taken into account, whilst for the chemical examination the following method is recommended.: Moisture is estimated by heating 1 gram of the raw or 2 grams of the finished lacquer upon the water-bath until transparent, and then in the hot-water oven for thirty minutes.Umshiol: The dried lacquer is treated with 10 (or 20) C.C. of absolute alcohol, and left for thirty minutes (or one hour), after which the liquid is filtered through a tared filter, and the residue washed with absolute alcohol. The filtrate and washings are divided into two portions, one of which is used for the estimation of the substances soluble in alcohol. The other is titrated with N-bariumTHE ANALYST 245 hydroxide solution, with phenolphthalein as indicator, the barium urushiolate formed uhder these conditions approximating closely to the salt formed in the equation- C,,H,,O, + 2Ba(OH), = C,,H,,O,Ba, + 4H,O, 1 gram of the urushiol thus corresponding to 6-14 C.C.Oils are obtained by deducting the urushiol from the substances soluble in alcohol, whilst gz~m arabic is estimated by extracting the residue on the filter with boiling water, and evaporating the extract, and the final insoluble residue on the filter gives the amount of nitro- geizozis substances. In the case of black finished lacquer the solution of substances soluble in alcohol is assisted by the addition of one or two drops of hydrochloric acid. The dissolved substances left on evaporation are then successively washed with hot water, hot sodium carbonate solution, and hot water, and redissolved in alcohol. C.A. M. Test for Mineral Oil. F. Schulz-Kolin. (Chem. Zeit., 1908, 32, 345.)-A solution of commercial picric acid in benzene gives a red coloration with mineral oils. The reaction depends on some impurity in, the crude picric acid (probably lower nitration products or higher homologues), since the pure acid gives no coloration. Rosin oil shows the same coloration as mineral oils, and the test may be regarded as a general one for the detection of the hydro-aromatic hydrocarbons and their oxidised derivatives. Since the pure animal and vegetable fatty oils show no change in colour with picric acid, this is a very convenient reagent for the detection of their adulteration.The presence of 1 per cent. of vaseline in a dark yellow coloured rape oil showed a distinct reddening on testing with picric acid ; the test may also be used with linseed oil varnishes. J. F. B. The Iodine Values of the Phenols. E. Wake and H. Ingle. (Jouwt. SOC. Che?n,. Iizd., 1908, 27, 315-31G.)-From the figures given it is seen that the meta- phenols and P-naphthol have iodine (Wijs) values which correspond with 6, 4, or 2 atoms of iodine per molecule, the values found being : Phenol, 267 ; carvacrol, 177 ; yhloroglucinol, 478 ; resorcinol, 690 ; and @naphthol, 178. A determination of the iodine value could thus be used for ascertaining their purity. The experiments with the phenols gave ample evidence of the reducing action of potassium iodide on iodochlorides.From a-naphthol, which by Hiibl’s method gives an iodine value of 264, by Wijs’ method adding potassium iodide first, iodine values from 195 to 200 were obtained; whilst when water was added to the test so as to precipitate the iodochlorides in the chloroform solution before adding t h i potassium iodide, an iodine value of 262 (31 = 265) was obtained. I n the case of phenol the iodine value found was 623 when water was added before the potassium iodide, whilst when the iodide was added first the value obtained was 267. I t was found that, while the ortho and para poly-phenols liberated iodine from Wijs’ solution, the meta derivatives did not do so. This test may be used to determine whether the hydroxyl groups are in the meta or in the ortho or p a m positions, and also to distinguish a- from @-naphthol, the former liberating iodine246 THE ANALYST.from Wijs’ solution. The best may be carried out as follows: The substance is dissolved in a small quantity of chloroform, and a quantity of freshly prepared Wijs’ solution is added. If any darkening of the solution takes place, the substance under examination contains ortho or para phenols or a-naphthol. Rosin also liberates iodine from the reagent, and its presenee in shellac may be detected by this means. The behaviour of the esters of the phenols is interesting, for whilst the free phenols absorb iodine, such is not the case with the esters (benzoates). W. P. S. New Method for the Estimation of Tannin.G. Metzges. (Cl~cm. Zeit., 1908, 32, 345.)-The author describes a method for the precipitation of tannin under the action of the electric current; the unreliable precipitation by means of hide powder is thus avoided, but all the other operations remain the same as in the old process. The solution containing tannin is subjected to the action of a simple long- phase alternating current between aluminium electrodes ; the precipitation of the tannin takes place gradually, and the end of the reaction is ascertained by drop-tests. The current may be obtained from an ordinary continuous current main at 110volts ; this is passed through a resistance of four 16-candle-power lamps arranged in parallel. The current is transformed by a rotating commutator operated by a small turbine or motor. An aluminium dish 100 mm. in diameter, of a capacity of 250 c.c., consti- tutes one electrode, and the other consists of a perforated aluminium disc of 60 mm. diameter. The solution, prepared by the standard method, is placed in the dish, and the disc electrode is adjusted at a depth of 1 cm., the volume of the liquid being 100 to 120 C.C. During the passage of the current the contents of the dish are frequently stirred. The precipitation of the tannin is complete a€ter about thirty minutes, a few drops of the solution being filtered off and tested with iron or gelatin. The precipitate is then removed by means of a dry filter, and 50 C.C. of the filtrate are taken for the estimation of the non-tannin in the usual way. The results are said to agree well with those obtained by the official hide-powder method. J. F. B.