116 THE ANALYST, ORGANIC ANALYSIS. Temperature of Combustion of Methane in presence of Palladiumized Asbestos. (Journ. SOC. Chem. Ind., 1905, xxiv., 1202.)-An investigation undertaken to ascertain to what extent methane is burnt when passed over palladiumized asbestos in presence of oxygen has shown that (1) the tempera- ture of combustion of a mixture of 1 volume of methane with 2 volumes of oxygen lies between 514' and 546'; (2) an increase in the speed at which the gases are passed through the tube causes a decided increase in the temperature of combus- tion; (3) a variation in the volumes of the gases influences the temperature of com- bustion, tending to raise it beyond the above-mentioned range ; and (4) the addition of hydrogen, even in large quantities, does not cause the methane to burn at a lower temperature.I t is concluded, therefore, that the usual method of fractional com- bustion of hydrogen gives reliable results, if the temperature does not exceed 500" to 550'. The catalytic action of the metal does not appear to be due to superficial oxidation, and in no case has anything approaching complete combustion been observed, even when the gas was 100' above its combustion temperature. H. J. Denham, W. H. S. The Volumetric Determination of Pentoses. A. Jolles. (Berichte, 1906, xxxix., 96, 97.)-From 0.2 to 1.0 gram of the substance under examination is treated with 200 C.C. of hydrochloric acid (specific gravity 1*06), and distilled in a current of steam until Bids reagent shows that no more furfural is formed, an additional 100 C.C.of the hydrochloric acid being introduced into the flask during the distillation. The furfural is now determined in an aliquot part of the distillate by treating it, after neutralization, with a known excess of standard potassium bisulphite solution, and titrating the excess with standard iodine solution after the mixture bas stood for two hours : C,H,O.COE + EKSO, = C,H,O.CH(OH)SO,K. Each C.C. of normal bisulphite solution is equivalent to 0.07505 gram of pentose. C. A. M. The Detection of Olive Oil extracted by Means of Carbon Bisulphide in Soap. J. Vamvakas. (Ann. de Chim. Anal., 1906, vol. 11, 53, !%.)--The soap manufactured in Crete is prepared almost exclusively from olive oil, and the author has long used the following simple method for determining whether the original oil had been extracted by means of carbon bisulphide: 2 grams of the soap are dissolved in 100 C.C.of 95 per cent. alcohol, the solution filtered, and its colour noted. If colourless or gray the oil was obtained by mechanical expression, whilst a yellow colour (with green fluorescence) indicates soap prepared from anTHE ANALYST. Specific Gravity. -- 0.9126 (21" C. 0.9120 (21" C. 0.9140 (l8O C. 0.9134 (18" C. - - 3,9389 (19" c. 3.9384 (18" c. 3.9160 (20" C. 1.9230 (23" C., 1.9130 (20° C. )'9120 (21' C.; - - - - - - 1.9136 (15' C.) )*910d (21" C.) 1.9108 (18" C.) 1.9604 (20" C.; 1.9596 (18" C.) 1'9161 (19O C.) ,09144 (22" C.) - - - - .I - - 0.9247 (14" C.) 0.9250 (15" C.) 0.9206 (20" 0.) - 117 extracted oil. The addition of a green or yellow dye-stuff, soluble in alcohol, to the soap is stated not to interfere with the test, since in that case the green fluorescence of the solution is even more pronounced (cf.ANBLYST, xxx., 313). C. A. M. On the Behaviour of the most Important Vegetable Oils towards Polarized Light. M. A. Rakusin. (Chem. Ztg., 1906, XXX., 143.)-The author suggests that animal and vegetable oils may be distinguished from mineral oils by means of polarized light, and has compiled the following table : OIL. A. LIQUID OILS. 1. Nowdrying Oils. Olive oil (Ob. olivarum) ,, (church use) .. ,, (gallipoli) .. Earth-nut oil ... .. 9 7 ... .. 9 9 ... .., Croton oil ... .. A1&6d oil (swkk't) . . ,, (Persian) ... 9 ) ,.. ..a ... ... olivi 'oil ... ... ,, (Provence oil) <.. oil (Prenci j .. . ,, (Japanese) ... $ 9 ... ... 9 9 ... ... ,, (01. raparum) ,, (refined) ... . . . Castor oil (Italian) 9 , 9 9 9 ... ... ... . . 4 ... ... Musiard oil (Sarepta) . . . ,, (black) ... Sesame oil (cold pressed) ,, (hot pressed) ,, 1878 ... ,, 1882 ... ,, 1882 ... ,, (Indian) ... ,, (01. sesame Gallicum) ,, 11. ... ... ... ... Must&d oil (white). Colour, etc. Yellow. Yellowish green. Y , 7 9 - - Dark 1 yellow. Light * yellow. I - - - Light yellow. j - - - Light yellow. - - Dark yellow. - - - - - - - Light yellow. - Ventzke with a Tube of Mm. 200 -- + 0-6 + 0.2 Opaque., -I- 0.2 - 0.4 - 0.31 ;o + 1-15 + 14-5 + 43 - 0'1 <- 0.1 - 0.7 + 0-6 + 0.2 f 0'3 - 2.1 - 1.6 - 0'23 D - 0'46 - 0.2 - 0.1 - 0.2 + 8.0 + 8.4 c+ 8-65 + 40.7 - 0.5 Opaque. + 3.1 + 7.2 + 4% -t 3.9 + 9.0 + 7.7 + 1.9 + 2-4 + 2.3 - 0.43 Analyst.i R* B. c. L. P. B. B. R. R. B. B. c. L. 1 R. I R. t R. w. P. - R. - B. - R. c. L. Remarks. Dark, with 200 mm. tube. - 7' to +24', with a Laurent. Benzene is with- out influence. Huil d'olive surfine. -5' to -10' with a Laurent, Belgian Go., Odessa. J. K. Glitschin, Sarepta. -9' with a Laurent. * B., Bischop ; C. L., Crossley and Le Sueur ; R., Rakusin ; W., Walden.THE ANALYST OIL. A. LIQUID OILS (continued). 2. Drging Oils. Cotton-seed oil ... Garden cress oil .. . Hemp-seed oil (raw) . . . Linseed oil (raw) > > > 7 ... ... Canieline oil ... Poppy-seed oil ... > > 9 9 a * * > > 9 7 - * a Niger-seed oil ... Walnut oil ... ... ' 6 Saiiior ' 9 oil ... Sunflower oil . . . ... ...a . . ... ... . .. ... ... ... ... ... P,. SEMI-SOLID ASD SOLID 011,s. Cocoanut oil ... .., 1 . Visco us 0% Is. Cocoanut oil in 50 pel cent. benzene solution Palm oil ... .., Palm oil in 50 per cent. benzene solution. 2. Solid Oils. 'Coca0 butter ... .. Cocno butter in 50 pel cent. benzene solution OTHER OILS. Laurel oil ... .. Laurel oil in 25 per cent Jasmine oil (01. jasstin Wild seed oil (01. resccla ether solution. pingue). pinpe). Colour, etc. -- Light yellow. bark green Dark - yellow. - - Dark yellow. - - Light yellow. - Almost :olourless. - - Light yellow. Nhite anc viscons. 2olourless Yellow paste. Light yellow. Pale yellow. Light yellow. Green paste. Green. Almost eolourless Yellow. Specific Gravity. -- 1.9220 (22" C.) 1.9256 (22" C. I 1'9314 (21" C.) - - - 0.9'230 (21" C.: - - 0.9219 (20" c.; - 0.9238 (18" C.: - - 0'9195 (22" C.: 0'9264 (20" C.- 0.9508 (18" C. - 0.9702 (20" C. - 0.9335 (19" C. - 0'9054 (IS" c. 0.9122 (18" C. O Veritzkc with a Tube of Mm. 2 00 -- - 0'1 0 0 paq ae . 7 9 - 0'3 + 0'28 - 0'1 0 to 0.17 0 + 0.1 0 to 0.86 + 0.15 - 0.3 -I- 0.17 to 0.66 + 0.1 Not exan + 0'19 x 5 Not exan 0.1 x 2 Not exan 0'1 x 2 Not exan - + 0.9 + 0.6 malyst. R. c. L. R. R. 3. c . L. R. c. L. B. R. c. L. R. B. c. L. R. - R. R. R. R. R. R. Remarks. -- !otton oil (OE. GossypX) . nactive oil. piltered. t 6 ' with a Lauren t. I" to + 4 with a Laurent. nactive. 1" to + 18' with a Laurent. -4' to +14' with a Laurent. 3- ystalline structure. Tasteless. A. G. L.THE ANALYST. 119 Detection of Artificial Colouring Matter in Fats.A. Olig and J. Tillmans. (Zed Untersuch. Nuhr. Genussm., 1906, vol. 11,94.)--If, during the rendering of a fat, the proteid matter be charred through over-heating, the fat becomes more or less tinted, and imparts a yellow colour to the acetic acid .ased in the test described by Sprinkmeyer and Wagner (cf. ANALYST, 1905, 244). I n case a coloration is obtained, the fat should be extracted with alcohol (which is also coloured by the oharred proteid matter), and the solution further tested for the presence of coal-tar dyes, etc. w. P. s. On the Detection and Determination of Paraffin Wax in Mixtures with Ceresin. F. Ulzer and F. Sommer. (Chem. Zeitg., 1906, xxx., 142.)-Various methods of examining mixtures of paraffin wax and ceresin are discussed. The best appears to be the determination of the refractive index at 90" C., the refractive index of paraffin wax with solidifying points varying from 50" to 60" C.lying between 2.0 and 4.0, whilst the values for ceresins solidifying between 68" C. and 71" C. vary from 11.5 to 13. A sample of German paraffin, however, with a solidifying point of 38" C. gave the high refractive index of 6-81. If only a small quantity of paraffin is present, it may be concentrated by boiling 5 grams of the sample for ten minutes with 100 C.C. of 95 per cent. alcohol, filtering hot, and evaporating, the refractive index of the residue obtained being compared with that of the original. Conversely, if only a small quantity of ceresin is present, 5 grams of the sample are dissolved in 50 C.C.of carbon bisulphide, and 100 C.C. of ether are added. Alcohol is then slowly added, the temperature being kept at 25" C. until a copious precipitate is obtained, which is washed with alcohol and ether, dried, and examined for ceresin. Good indications are also obtained by using Crismer and Motton's method of determining the critical temperature of solution in various solvents, ethyl alcohol being preferred. The critical temperature of solution of various paraffins was found to be, in ethyl alcohol, 155.5" to 158 ; amyl alcohol, 47" to 54" ; acetone, 67.5" to 77" ; and acetic anhydride, 163" to 176" ; whilst some samples of ceresin gaxe the values 68" to 71°, 174" to 177O, '73*5" to 76", 95" to 98", and 191" for the same solvents. A differentiation may also be made by capillarity, ceresin rising much less in filter-paper than does paraffin (6 cm.as against 10 cm. in one hour at 100" C. in the case of two samples compared), A. G. L. Determination of Fatty Acids in Textile Soap. Gerhard Kruger. (Chem. Zeit., 1906, xxx., 123.)-Ten grams of the cut-up soap are weighed out into a tared porcelain crucible of 150 C.C. capacity, dissolved in water, and heated with 20 C.C. of dilute (1 : 10) sulphuric acid on a water-bath until the fatty acids have become clear, From 5 to 10 grams of beeswax are then stirred into the fatty acids, and the whole allowed to cool. The solidified fatty cake is then lifted out of the crucible, the acid is poured out, and the cake treated with successive quantities of water until the latter ceases to show an acid reaction.The crucible and fat are then dried for one hour at 70" C., moistened with alcohol and dried for another hour at 10.0" C., after which they are weighed. The error due to any fatty acid passing into solution in the acid liquid120 THE ANALYST. may be neglected, since even for palm-nut oil soaps it is quite small, whilst cocoanut oil is not used for making textile soaps. A. G. L. Note on Commercial Oil of Turpentine. W. Vaubel. (Zed Ofensaztl. Chem., 1905, xi., 429-432.)-The author recommends the determination of the bromine absorbing power as a means of distinguishing between genuine oil of turpentine and its adulterants. American oil of turpentine was found to have a bromine value of 110 to 115 ; Russian, 72 to 97 ; resin '' essence " (a product of the distillation of resin), 89.The figures express the grams of bromine required per 100 grams of oil. Russian oil of turpentine is distilled from the roots of the trees, and is an unsatis- factory substitute for the genuine oil. w. P. s. The Physical Characteristics of Certain Copals. Bottler. (Chem. Rev. Fett a. Harx. Ind., 1906, xiii., 1-5.)-A comparative examination has been made of the characteristics of all the more important copals met with in commerce, many of the results being in tabular form. The physical properties included the appearance of the surface, the colour, transparency, lustre, appearance on fracture, specific gravity, hardness, fusibility and solubility. The specific gravities of the copals in most demand ranged from 1.03 to 1-07 for the substance containing air-bubbles, a higher value being obtained after removal of the air. Speaking generally, the smaller the difference between the densities determined before and after removal of the air, the more valuable the copal.Thus the following differences were observed : Lindi copal, 0.001 ; Zanzibar copal, 0.0015 ; red Angola copal, 0.014 ; Brazil copal, 0-014 ; Cameroon copal, 0.015 ; Manila copal, 0.059 ; Hymenea (South-American) copal, 0.0615; and Kauri copal, 0.064. In the author's opinion the Brazil copal is really a West African and not an American copal. The degree of hardness is an important factor for distinguishing between the different kinds of copals. The hardest is Zanzibar copal, and the other important kinds can be ranged in the following scale : Hard- Mozambique, Lindi, red Angola, Sierra Leone (Kiesel), yellow Benguela, white Benguela, Cameroon, and Congo copals ; Medium-Manila, white Angola, and Kauri copals ; Soft-Sierra Leone (new), Hymenea, and Brazil copals.The melting-points of copals range between 90" and 360" C. The following results were obtained by the author: Hymenea, 95" C.; Cameroon, 108" C.; Manila, 112" C. ; Manila (yellow, hard), 135" C. ; Kauri, 126" C. ; Kauri, 140" C. ; yellow Benguela, 170" C. ; white Benguela, 175' C. ; Congo, 180" C. ; Sierra Leone, 185' C. ; Kiesel, 220' C. ; white Angola, 245" C. ; Lindi, 246' C. ; Zanzibar, (a) 259" C., ( b ) 265" C.; and red Angola, 305" C. The solvents tried included chlorhydrin, terpineol, and carbon tetrachloride, in addition to the older solvents.A rapid method of dissolving copals (e.g., West African varieties) consists in heating them for forty-eight hours at 100" C., mixing them with sand or glass powder, digesting the mixture for twenty-four hours with anhydrous ether, and finally adding an equal quantity of hot alcohol. Turpentine oil has usually only a solvent action on copals when it contains ozone. The different copals can be arranged in the following order as regards their solubility in the solvents most commonly employed : White Angola,THE ANALYST. 121 Manila, Kauri, Brazil, Congo, Sierra Leone, yellow Benguela, red Angola, white Benguela, Kiesel, Cameroon, Lindi, and Zanzibar copals. C. A. M. Recovery of Iodine from the Residues obtained in Hubl's Method. A. olig and J.Tillmans. (Zeits. Untersuch. Nahr. Genussm., 1906, vol. 11, 95-97.) -The solutions obtained after the final titration in determinations of the iodine value of fats by Hubl's method are collected until a, good quantity is obtained. After removing the chloroform by means of a separating funnel, the aqueous portion is rendered strongly alkaline with sodium hydroxide, and evaporated as far as possible. The mercury compounds (oxide, basic carbonate, and some metal) are filtered 0% washed, and the filtrate again evaporated to dryness and ignited. A little mercury will still be present, and care must be taken during the ignition. The residue is dissolved in water, filtered from any insoluble matter, and the solution then rendered strongly acid with hydrochloric acid.The mixture is now warmed, and a concen- trated potassium bichromate solution is added until all the iodine has been precipi- tated. The liquid is then decanted, the iodine is washed with a small quantity of water, and distilled from a retort in a current of steam. The distilled iodine is collected in a well-cooled receiver, from which it may be readily removed in its wet state, and then dried or sublimed. w. P. s. Notes on the Determination of Calorific Values by means of the Bomb. I). Aufhauser. (Zeits. angew. Chem., 1906, xix., 89.)-In order to make the temperature corrections as small as possible, the water used should be initially as much below the normal temperature as it is finally above it. The temperature of the water in the calorimeter may be most conveniently adjusted for this purpose by putting colder water into the calorimeter, placing the bomb in position, starting the stirrer, and then warming the whole to the required temperature by means of a small electric heater, preferably a cylindrical electrical lamp.The lamp should be wetted before it is plunged into the water in order to obviate the error due to adhering water when it is taken out. A. G. L. The Volumetric Determination of Organic Hydrosulphides and Thio Acids. P. Klason and T. Carlson. (Berichte; 1906, xxxix., 738-742.)-Titration of organic hydrosulphides with an aqueous solution of iodine gives under suitable conditions quantitative results in accordance with the equation : 2R. SH + I, = R,S, + 2HI. Thiocyanic acid, however, does not react in this way.The presence of bicarbonate is not only unnecessary, but may lead to further oxidation. The weighed quantity of the hydrosulphide is dissolved in alcohol and titrated with N-iodine solution until a faint yellow colour appears. I t is essential that there shall be sufficient alcohol present to keep the bisulphide formed in solution, since otherwise it too can absorb iodine, and the results will be too high. The resulhs of test experiments with different classes of thio compounds, such as p-thiocresol, methyl and ethyl hydrosulphides,122 THE ANALYST. thioglycollic, and thioacetic acid, show that the method is capable of great accuracy. Rosenheim and Davidson found that the reaction between thioglycollic acid and iodine in sodium bicarbonate solution gave a, quantitative yield of dithioglycollic acid; but the author finds that the results thus obtained are not constant, and are invariably too high owing to further oxidation with the formation of thioacetic acid. This latter acid, too, also undergoes further oxidation in a bicarbonate solution, acetyl- bisulphide being produced.Aromatic hydrosulphides--e.g., thiophenol, P-thionaphthol, and p-thiocresol- are so strongly acid that they form salts with alkalies in neutral solutions, and can therefore be titrated with standard alkali solution, phenolphthalein being used as indicator. The more carbon the molecule of the compound contains, the greater the accuracy of the results. With alipathic hydrosulphides the end reaction is not sharp, and thioglycollic acid cannot be titrated with alkali.either in aqueous or alcoholic solution. C. A. M. On Quantitative Determination by Means of the Immersion Refracto- meter. H. Matthes. (Chem. Ztg., 1906, xxx., 101.)-The author severely criticises some applications of the use of the immersion refractometer made by Wagner (Ztschr. ofentl. Chem., 1905, xi., 404), especially in the case of sugar analysis. For legitimate uses of the instrument, such as the control of beer, wine, etc., prepared in the same way and under the same conditions, and the control of the strength of standard solutions, he refers to his own work (Ztschzr. arzalyt. Chem., 1904, xliii., 83). A. G. L. Simplified Ultimate Organic Analysis for Scientific Purposes. M. Denn- stedt. (Chem. Zeit. Rep., 1905, xxix., 390.)-In the use of the simplified method (see ANALYST, xxx., 135) of the author a diiliculty arises from the fact that, as some substances require different treatment in the combustion, these must be burnt in succession.The chief point of the “quick” method is that the boat containing the sub- stance is not placed directly in the combustion tube, but in a, narrow, hard glass tube, which may take any of three forms : (1) The form open at both ends, a, ’Fig. 1 ; The author now suggests some improvements. FIG. 1. (2) that with the hinder end closed, b, Fig. 1; or (3) that with a double current of oxygen, Fig. 2. The last named is fitted with a capillary and a bubble counting arrangement through which the oxygen enters the inside of the tube. AT-piece of somewhat wider bore fits over the capillary, and is provided with a cork to fit into the main combustion tube. The main current of oxygen passes through the calcium chlorideTHE ANALYST. 123 tube and the side tube of the T-piece. The bubbling apparatus and the calcium chloride tube are each connected to the ordinary drying apparatus by rubber tubing, which allows the tube to be withdrawn with one hand for introduction of the boat, etc. Form a is suitable for the combustion of substances which decompose slowly, with formation of much carbon difficult to burn--e.g., sugar, albumin; form b is for use with easily volatile or moderately volatile substances, which do not give a separation of difficultly combustible carbon-e.g., alcohols, benzol, aniline, etc. The third kind of tube is serviceable for all substances without exception. The regulation of the combustion is especially easy, as this can be effected not only by the flame, but also by increasing or diminishing the rate of the inner current of oxygen. The tubes can be obtained from Emil Dittrnar and Vierth, Hamburg. E. K. H.