24 PROCEEDINGS OF THE AMERICAN ACADEMY. 



this hydrocarbon has been carefully determiued, * further exam- 

 ination was not deemed necessary. The temperature rose rapidly 

 to 5°, and between 7° and 9° 20 grams of a distillate collected, mostly 

 between 7° and 8°, the boiling point of a hydrocarbon which was 

 separated by Warren from Pennsylvania petroleum, and which was 

 regarded by him as one of the butanes. Since the atmospheric tem- 

 perature was in the vicinity of 30° when these distillations were in 

 progress, special care was necessary to preserve the distillates, and the 

 ice accidentally becoming exhausted in the ice-chest, the distillate col- 

 lected at 0° burst the bottle, and the one at 8° forced out the stopper 

 and volatilized. Of the two possible butanes, the boiling point of one 

 is without question 0°. The other seems to have been obtained by 

 Butlerow t from isobutyl alcohol, and the boiling point assigned to it 

 was — 17°. 5, Under more favorable conditions, we shall collect a 

 larger quantity of this distillate, to determine by its chemical behavior, 

 as well as by its constancy in boiling point, whether it be a definite 

 compound, t 



Considerable quantities of distillates collected below 30°, but by 

 continued distillation they were mostly separated into higher and 

 lower constituents, indicating the absence of individual products. In 

 the vicinity of 30° the fractions were large, amounting to 300 grams 

 between 28° and 32°. After the ninth distillation, 75 grams collected 

 between 29° and 30°, with the barometer at 747 mm. A vapor 

 density determination gave 2.52, required for pentane 2.49. This 

 product was, therefore, isopentane. boiling point 30°. Between 36° 

 and 37°, 75 grams distilled, and this distillate was shown by its vapor 

 density to have the composition required for pentane ; a vapor density 

 determination gave 2.49, required for pentane 2.49. This sub- 

 stance therefore corresponded to normal pentane, boiling point 37° 



* Ronalds, Journ. Cliem. Soc, XVIII. 54 ; C. M. Warren, Mem. Amer. Acad. 

 (N. S.). IX. 156. 



t Ann. Chem. Pliarm.. CXLTV. 10. 



t We have since obtained .50 .crams of an oil that collected at 8° to 9° with 

 very small amounts above and below these limits. A vapor density determina- 

 tion by the Hofmann method gave the following result: — 



0.0717 gram of the oil gave 45.5 c.c. of vapor at 16°, and under a tension of 

 48.1 cm. of mercury. 



Required for 0411,5. Found. 



2.01 2.04 



For further proof as to the composition of this distillate, an examination of its 

 halogen and other derivatives is now in progress. 



