Physics. ; 411 
exceeded, so that the active force has its direction inverted. The molecules 
then vibrate in the direction of the atoms, and the condition of fluidity 
The outer atom molecules will follow, and since the cause of 
motion, namely the great amplitude of vibration, constantly acts, there 
will be a constant motion of the particles with r t ach other. In 
measures that the diameter of the similarly move 
small as to correspond nearly with the wave-length of red light and still 
more nearly with that of radiant heat, and considers this as a strong 
confirmation of his theory.—Pogg. -Ann., exviii, 79. Ww. G. 
4. On the absorption of gases by charcoal ; by Dr. R. Avaus Surrn, 
B 
e 
“ 
co 
s 
3 
= 
os 
tS 
=a 
5 
te 
io] 
Qu 
Ss 
5 
° 
5 
8 
seconds, according to the quality of the charcoal. Hee 
(3.) It does not absorb hydrogen, nitrogen, or carbonic acid for the 
Same period. 
(4.) Although the amount absorbed is somewhat in the relation of the 
condensibility of the gases by pressure, this is not the only quality regu- 
ing the absorption, of oxygen at least. 
(5.) When it is sought to remove the oxygen from charcoal by warmth, 
carbonic acid is formed, even at the temperature of boiling water, and 
slowly even at low temperatures. : ; : 
(6.) Charcoals differ extremely in absorbing power, and in the capacity 
of uniting with oxygen, animal charcoal possessing the latter property in 
4 greater degree than wood-charcoal. 
__ (7.) Nitrogen and hydrogen, when absorbed by charcoal, diffuse into 
the atmosphere of another gas with such force as to depress the mercury 
uarters of an inch. 
Am. Jour. Sct.—Szconp Series, Vou. XXXVI, No. 108.—Nov., 1363. 
53 
