DESTRUCTIVE DISTILLATION OF ANIMAL MATTERS. 



591 



Carbon, . 

 Hydrogen, 



Nitrogen, 



I. 



. 71-64 



. 8-17 



II. 



71-42 

 7-71 



in. 

 71-84 



7-77 



IV. 



71-61 

 8-05 



V. 



71-54 

 7-80 



VI. 



71-51 



7-74 



VII. 

 71-54 



7-77 



Mean. 



71-58 



7-85 



20-57 



100-00 



These results correspond with the formula C 8 H 5 N, which requires the fol- 



lowing numbers :— 



8 eq. carbon = 48 71*64 



5 ... hydrogen, = 5 7'46 



1 ... nitrogen, =14 20-90 



67 100-00 



As none of the compounds of pyrrol are sufficiently definite to admit of their 

 being used for fixing its atomic weight, recourse was had to the determination of 

 the density of its vapour for this purpose, and three experiments were made at 

 different stages of the investigation. The first was made after the pyrrol had 

 received six rectifications and one treatment with acid, and its deviation from 

 that required by theory showed that the material was not yet quite pure. The 

 second, made after fourteen rectifications, and agitation with three successive por- 

 tions of sulphuric acid, showed a close approximation to the theoretical number, 

 while the third, made with the fragrant pyrrol, was as exact as could be desired. 

 The details are as follow : — 





I. 



II. 



III. 



Temperature of the air, 



16° c. 



11° 



13 



vapour, 



198° 



186° 



201 



Excess of weight of the balloon, . 



0-2285 grammes. 



0-2185 



0-1610 



Capacity of do. . 



324-5 c. c. 



3285 



303 



Barometer, 



767 m. m. 



744 



764 



Residual air, 







1-5 



4 



Density of the vapour, 



2-52 



2-49 



2-40 



ie formula C 8 H 5 N requires : — 









8 vol. carbon vapour, 



0-8290 x 8 = 6-6320 







10 ... hydrogen, ... 



0-0692 x 10 = 0-6920 







2 ... nitrogen, 



0-9713 x 2 = 1-9426 







9-2666 



= 231 



Although the properties of the pyrrol now described are entirely distinct from 

 those attributed to this substance by Runge, it cannot be doubted that they are 

 really identical, although it is equally unquestionable that he never isolated his 

 pyrrol, but merely obtained a small quantity of it held in solution by some gas, 

 most probably a hydrocarbon. For this reason I think it right to retain his name, 



VOL. XXI. PART IV. 7 U 



