— 125 — 



^ by Louise 1 ) in testing turpentine oil. The experiments of Queysamre with 

 laevorotatory French oil have been amplified by investigations conducted 

 by Gallon 2 ). The samples of oil under examination possessed the following 

 constants: d 15 o 0,8675 and 0,8682, n D25 o 1,4668 and 1,4655, « D10O + 40,32° 

 and 39,99° respectively. The constants quoted in the second set of figures 

 refer to another, but rather "older", sample of the same oil, the difference 

 in age being shown in the somewhat slighter solubility of the "older" 

 sample. But on the whole, the dextrorotatory oil was not so soluble in 

 aniline as the lasvorotatory sample which had previously been examined. 



That the chemical testing of turpentine oil offers great difficulties is 

 evident from the numerous publications on the subject. P. van derWielen 3 ), 

 who has been engaged in the investigation of this oil, proposes a mod- 

 ification of the sulphuric acid method. To 80 cc. sulphuric acid (d 1,698) 

 in a flask of about 1 litre capacity, he adds 20 cc. of the oil under ex- 

 amination, and allows the mixture to stand for an hour under repeated 

 shaking. After adding 300 cc. water the oil which has not been attacked 

 is distilled over into a bottle with a graduated neck. The coefficient of 

 of refraction as well as the separation temperature of the solution in 

 aniline are determined. It is also necessary to know the refraction of the 

 original oil. According to van der Wielen, an addition of hydrocarbons 4 ) 

 may be detected positively from the above data as well as from the 

 quantity of oil which has not been polymerised by sulphuric acid. The 

 author has examined by this method a large number of samples of turpen- 

 tine oil as well as various substitutes and mixtures with benzene, hydro- 

 carbons and carbon tetrachloride, and has collected the results in 

 table-form. 



For determining the evaporation-residue of turpentine oil, Herzfeld* 

 and also Kollo 5 ) recommend the embedding of the platinum dish in a 

 sand-bath, and the heating of the latter to 155° before filling-in the oil. 

 In order to obviate the risk of explosion of the suddenly-generated vapour, 

 a tin-ring is to be affixed below the rim of the dish. Wolff 6 ) has observed 

 that when the dish is merely embedded in sand, the last particles of oil 

 frequently creep over, and he obviates this trouble by surrounding the dish 

 with a tin-cylinder about 2 inches in height and of a diameter exceeding 

 that of the upper portion of the dish by nearly half an inch. This cylinder 

 is stuck in the sand to a depth of about V 4 inch. 



x ) Comp. Report October 1910, 139. 



2 ) P. E. Gallon, Sur la solubilite reciproque de V essence de tercbenthine dextrogyre et 

 de V aniline. Bordeaux 1911. From a reprint kindly sent to us. . 



3 ) Pharm. Weekblad 8 (1911), No. 35. 



*) By hydrocarbons the author apparently understands petroleum-hydrocarbons. 



5 ) Comp. Report April 1910, 116. 



6 ) Farbenzeitung 16 (1911), 2746. Quoted from Chem. Zentralbl. 1911, II, 1181. .■•;; .. . 



