148 PROCEEDINGS OF THE AMERICAN ACADEMY. 



remained of the quantity taken 17 grams, with a loss of 32 per cent. A 

 portion of the nitro product crystallized on standing, and after several 

 crystallizations from hot alcohol, in which it was sparingly soluble, the 

 melting point could not be raised above l64°-16o°. In testing the action 

 of sulphuric acid alone on the distillate 171°-172°, 25 grams of the crude 

 oil was agitated with three succeijsive portions of concentrated sulphuric 

 acid, washed with sodic hydrate and water, and dried. In the first treat- 

 ment, in which the oil lost in weight 1.8 grams, the acid was badly dis- 

 colored; the subsequent portions were not affected. The oil was next 

 heated gently with fuming sulphuric acid with agitation, which caused con- 

 siderable blackening, washed first with concentrated sulphuric acid, then 

 with sodic hydrate and water, and dried. After the last treatment, the 

 oil weighed 19.8 grams, with a loss of 25 percent. 



It is evident from these observations that some care is necessary in 

 attempting to purify these hydrocarbons with concentrated nitric acid. In 

 the cold or under a gentle heat not prolonged, the decomposition is 

 probably not serious. But at higher temperatures, as shown above, the 

 action may proceed too far. The purified oil gave satisfactory results on 

 analysis : — 



I. 0.1373 gram of the oil gave 0.4247 gram COg, and 0.1900 gram 

 H2O. 

 II. 0.1459 gram of the oil gave 0.4520 gram C02,and 0.2090 gram HoO. 



Two determinations of the specific gravity at 20° of this oil in different 

 preparations gave 0.7519 and 0.7513. 



In a still more extended purification, some of the crude distillate was 

 agitated thoroughly with the mixture of nitric and sulphuric acids, 

 allowed to stand several hours with the acids, and, after washing, heated 

 for some time with tin and hydrochloric acid. The washed and dried 

 oil was then warmed with fuming sulphuric acid, washed, dried, and dis- 

 tilled. It then gave 0.7482 as its specific gravity at 20°, more nearly 

 approaching the specific gravity of the Pennsylvania decane 173°, 0.7467, 

 and analysis indicated that the remaining oil had the composition of the 

 general formula C„H.2„+o : — 



0.1449 gram of the oil gave 0.4494 gram CO^, and 0.2051 gram HaO. 



