218 Scientific Intelligence. 
(8.) The sum total of heat which at any given station is fur- 
nished by the reflection of the lake, starting from the moment 
w 
compared to that which is presented directly by the line during a 
shorter period. Thus, for example, we find at the Dézaley station, 
on the 28th of September, reflection furnished a total of heat 
sun furnished during his last half hour, ete. 
(7.) Comparative observations made with the bulbs used in 
these experiments have served to convert their relative indications 
into absolute values, expressing the absolute quantity of heat 
reflected by the lake from one square meter of surface, normal to 
the ray, from the moment this reflection began to be sensible until 
the sun was almost set. We have the following values at— 
Station: Ouchy, Sept. 12 104 calories. 
Tour-Haldimand, Oct .5,....-------- Beers 
7 Detaley, Bem. WG Sas Ae, ee aaa 
“ “c Oct. 1 Re 134 “6 
These numbers are somewhat in error from the disturbing causes 
before named. is error certainly does not exceed a fourth of 
the values given, and it is very probable that the true quantity 
of heat furnished by reflection is greater rather than less than 
that stated. * * * 
id 
Rendus, \xxvi, 1572. 
2 ermodiffusion.—W . : 
ment on various porous substances the theoretical proposition 
assumed by Carl Neumann,* that if a limited portion of a gas en 
¢ 
tion, and the two projecting ends were each connected air tight MY | 
means of caoutchouc, with another horizontal glass tube, whic 
* Berichte der Kénigl. Sach Gessell. der Wissen., Sept. 15, 1872. 
