608 EXPEKIMENT STATION EECOED. 



The fatty acids from the polymerized triglycerids of the wood oil, as well as 

 those from the other drying and semidrying oils, do not have this property. 



Wood oil can be completely polymerized upon heating for a short time at 

 very high temperatures. Under such treatment it will not gelatinize. The oil 

 polymerizes considerably faster than linseed oil at corresponding temperatures, 

 liime, litharge, and oxidation products together with a large number of metals 

 at higher temperatures catalyze the polymerization of the elaeomargaric acid 

 triglycerid into the intermediate product. Oxygen does not act as a catalyzer 

 except indirectly. The pure polymerized product of the oil dries very slowly. 

 It is thus characterized, as containing large percentages of polymerized' 

 triglycerid, by this slow rate of drying. 



The carbohydrates of pine •wood, E. Haggll-nd {Biochem. Ztschr., 10 (1915), 

 No. 5-6, pp. 416-425). — The composition of the carbohydrates of pine wood was 

 determined qualitatively and approximately quantitatively. On hydrolysis they 

 yielded chiefly xylose and mannose, together with some fructose and galactose. 

 Glucose could not be found. On hydrolysis with dilute acids at higher tem- 

 peratures the carboliydrates were first changed to a soluble form and on con- 

 tinued heating were partly converted to glucose. 



An effective apparatus for evaporating aqueous extracts by means of a 

 current of air, T. B. Aldrich (Jour. Biol. Chcvi., 23 (1915), No. 1, pp. 255-259, 

 pi. 1, fig. 1). — An arrangement for the evaporation of solutions or the drying 

 of biological materials which are susceptible to higher temperatures is de- 

 scribed. The apparatus has given excellent results and the author claims cer- 

 tain advantages for its use over vacuum distillation. 



A check valva for suction flasks, G. 1'. Walton (Jour. Indus, and Engin. 

 Chcm., 8 (1916), No. 1, p. 51, fig. 1). — A device which allows continuous filtra- 

 tion by suction in automatically emptying the flask is describe<l in detail. It 

 consists of a form of ball check valve, easily constructed and readily fitted 

 to any of the usual types of suction flasks. The device as described has been 

 found to be very convenient and a time saver in crude fiber, reducing sugar, 

 pentosan, and other determinations where the filtrate and washings are re- 

 jected. 



Note on the micromethod for gasometric determination of aliphatic amino 

 nitrogen, D. D. Van Si.yke (Jniir. Biol. Chnn., 23 (1915), No. 1, pp. 401-.',09, 

 fig. 1). — By a slight modification of the gas burette In the apparatus pre- 

 viously noted (E. S. R., 31, p. 610) it is found possible to secure the same degree 

 of accuracy of results by reducing the size of the apparatus one-half and using 

 correspondingly small amounts of material for the determination. 



The recovery of molybdic acid from phosphorus-determination residues, 

 A. D. Berkhout (VcrsUtg. LnndhouKlc. Ondcrzocl;. Rijlcslnndbouirprocfstat. 

 [Ncthcrlandali, No. IS (1915), pp. 8S-S5). — The following procedure is recom- 

 mended for the recovery of molybdic acid from the residues obtained in the 

 method of Grote (E. S. R., 22, p. 510) : 



Two and six-tenths kg. of the precipitate, which has been washed and air- 

 <aried, is dissolved in 2 liters of 2.5 per cent ammonium liydroxid and 4 liters 

 ojf water. Four liters of magnesia mixture are added, and ammonium mag- 

 nesium phosphate is precipitated after standing several days. This is filtered 

 and washed with 2.5 per cent anunonium hydroxid. (The ammonium magnesium 

 pliospliate, dissolved in nitric acid, may be used to recover molylxlic acid from the 

 mother liquor of precipitates.) The clear filtrate is evaporated on the water bath 

 to incipient precipitation of ammonium chlorid, several portions of 100 cc. each of 

 10 per cent ammonium hydroxid being added during tbe evaporation. The precipi- 

 tated ammonium molybdate is transferred to a porcelain mortar, mixed, and 



