128 PROCEEDINGS OP THE AMERICAN ACADEMY. 



Although the composition as shown by analysis seemed to be suffi- 

 cient to demonstrate the presence of a hydrocarbon at this point, evi- 

 dently analytical data alone would be insufficient, unless supported by a 

 constant boiling point. The distillate used in the determinations de- 

 scribed above was obtained after a long fractional separation, but without 

 purification except the removal of sulphur compounds, until after the 

 distillations were made. To prove beyond question the constancy in 

 boiling point, another portion of the crude distillate after the fifteenth 

 distillation was thoroughly agitated and warmed with fuming sulphuric 

 acid, washed, dried, and the distillation continued fourteen times longer. 

 About 100 grams of the oil collected so that it distilled at 163°-164°, 

 mostly at 164°, under a tension of 760 mm., and with the mercury 

 column all in the vapor. There seems therefore to be no reasonable 

 doubt that Pennsylvania petroleum contains a decane with this boiling 

 point. That this hydrocarbon is a decane is shown also by a determina- 

 tion of its molecular weight by the Beckmann method, which gave 142 ; 

 and the formula C10H22 requires 142. 



In forming the chlorine derivative of the hydrocarbon CioHoo, boiling 

 point 163°-164°, from Pennsylvania petroleum, 45 grams of the purified 

 hydrocarbon was subjected to the action of chlorine in sunlight with a 

 sheet of paper interposed, until it increased in weight 17 grams. The 

 chlorine was delivered rapidly above the oil, and it was absorbed as fast 

 as it could be added. Hydrochloric acid escaped with effervescence, and 

 the rapidity of the reaction generated sufficient heat to maintain the tem- 

 perature in the vicinity of 70°. With a slower stream of chlorine in 

 other experiments the heat was dissipated without heating the oil, al- 

 though the chlorine was as readily absorbed. Without further treatment, 

 the chlorine product was subjected to fractional distillation in vacuo 

 under tension of 80 mm. After ten distillations, approximately 6 grams 

 collected at r2.5°-130°. which determinations of chlorine, carbon, and 

 hydrogen showed to be mouochlor decane : — 



I. 0.2181 gram of the oil gave 0.5460 gram COo, and 0.2265 gram 



HoO. 

 II. 0.2024 gram of the oil gave 0.1660 gram AgCl. 



n. 



20.29 



