Chemistry and Physics. 295 
—WNature, xiv, 264. BE. 0. P. 
9. Explosion of Fire Damp.—M. Matxiarp has measured the 
fire-da 
rapidly, becoming né/ with a proportion 
of 077 vol. on the one hand, and 0°165 vol. on the other, below 
uals connected by a metallic wire. Their inner terminals are at- 
ached to two points placed near a registering cylinder connected 
The connection for one point is a short wire, and 
for the other a telegraph line. The two condensers are discharged 
de ously by connecting their outer terminals with the earth 
d , 
charges was inappreciable, and certainly did not exceed five mill- 
lonths of a second. With a line 25°36 kms. long, the retardation 
8. 
se times are nearly proportional to the length of the lines, 
bi capacity of the two shorter lines was ‘15 and ‘063 microfarads 
von is much greater than that required to charge eo cable 
_ length —Pogg. Ann.; elvii, 309; Journ. de Phys., v, 226. 
E. ©. P, 
