eyo. mets 
DESTRUCTIVE DISTILLATION OF ANIMAL MATTERS. 591 
I. II. III. IV. Vv. VI. VII. Mean. 
Carbon, . . 71:64 71:42 71:84 71-61 71:54 71:51 71:54 71:58 
Hydrogen, cut ae 771 7717 8:05 7:80 774 777 7:85 
Nitrogen, : ike a6 HE i fete sie 20°57 
100:00 
These results correspond with the formula C,H,N, which requires the fol- 
lowing numbers :—* 
8 eq. carbon = 48 71:64 
.. 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 If 
Temperature of the air, ; : 16° ¢. Me 13° 
: vapour, . : 198° 186° 201° 
Excess of weight of the re : é 0:2285 grammes. 0:2185 0-1610 
Capacity of do. . ; : 324:5 ¢. c. 328°5 303 
Barometer, a A 7 767 m. m. 744 764 
Residual air, . : : “ 0 15 4 
Density of the vapour, . - 5 2°52 2°49 2°40 
The formula C, H, N requires :— 
8 vol. carbon vapour, 0°8290 x 8 = 6-6320 
10 ... hydrogen, --- 0-0692 x 10 = 0:6920 
2... nitrogen, -- O9713 x 2 =1:9426 
9-2666 
————e eo 
4 
Although the properties of the pyrrol now described are entirely distinct from 
those attributed to this substance by Runex, 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. 7U 
