340 FF. W. Clark—Molecular Heat of Similar Compounds. 
It has been proved by Will (Ann. Chem. Pharm., xlv, 106) 
that ammonia is not formed by the union of free nitrogen with 
nascent hydrogen; hence the gain of nitrogen in the experi- 
ments described above is not due to that reaction with the nas- 
cent hydrogen produced in decomposition. ; 
We must then conclude that decaying organic substances, in 
the presence of caustic alkali, are able to fix free nitrogen without 
the gain being manifest as nitric acid or ammonia, and probably 
without the formation of these bodies. 
In conclusion, I wish to express my obligations to Prof. 8. W- 
Johnson, at whose suggestion these experiments were under- 
taken, for the use of materials and apparatus, and for many 
valuable suggestions in regard to the conduct of the experl- 
ments. 
Art. XXX.—On the Molecular Heat of Similar Compounds ; 
y Frank WiaGLesworto Cuarkz, §.B., Professor of 
hemistry and Physics in the University of Cincinnati. 
It is commonly stated in the text-books of physics that sim! 
lar compounds byes ual molecular heats. Thus, for the 
chlorides of the general formula MCI, the product of the specific 
heat into the atomic weight gives approximately a single value. 
But the equality, under ordinary circumstances, is only ap- 
proximate, as a few examples will show. 
Taking the chlorides of the alkaline metals, we have the 
following good determinations of specific heat: LiCl, ‘28213; 
