386 Scientific Intelligence. 
: I. PHYSICS AND CHEMISTRY. 
1. On the heat of combination of boron with chlorine and omy- 
gen.—Troost and HauTEFrevit_e have communicated to the Acad- 
emy of Sciences a memoir on t 
which the rapidly increasing importance of thermo-chemistry 
rimeter. The heat measured was thus the sum of the heat of com- 
bustion proper and of the heat evolved in the combination or double 
decomposition of the chlorid with water. The heat due to the last 
mentioned reaction was then determined by a special experiment. 
Paha eke 
1 
of boric acid in an equal weight’ of chlorhydric acid of the same . 
degree of dilution, as determined by direct experiment. In t ; 
manner the heat of combustion of boron in oxygen was found to 
be 158600 units for one equivalent (old style) of boron. 2 ‘ 
boron employed was in the amorphous modification; the authors : 
promise similar determinations for the other forms of this element. 
G. 
“ : 
2. On the heat of combination of silicon with chlorine and oxy- 
gen.—The same authors in a second communication have given 4 
tracted. The mode of experimenting and the corrections ted 
the same as in the case of boron described above. It was foun 
that one equivalent of chlorid of silicon acting upon 140 times its 
i h 
