7 
Chemistry and Physics. i 280 
value of this constant than their isomers not having this union ; 
and the value is larger when carbon atoms are doubly united than 
when carbon is thus joined to oxygen. Longuinine has proved the 
same to be true of the heat of combustion. ; an unsaturated 
i com- 
Idehyde, or ace- 
tone. 7th, since if two bodies having the same molecular formula 
give different quantities of heat on combustion, they must con- 
tain different quantities of energy, it follows that the internal 
The energy of a body consists of the vis viva of its moving par- 
ticles and of its interior work, the latter only, tending to diminish 
the torces uniting these particles and so to produce disaggrega- 
Hon. But the vis viva of isomeric bodies is equal; hence the 
reverse of the fact. This conclusion is supported by Kopp’s and 
by Buff’s results showing that the volume of : 
only singly united ones; and also by t 
Kekulé that on oxidation of a body with doubly united atoms the 
molecule first breaks at the double union.—Ber. Berl. Chem. 
Ges., xiv, 2533, Nov. 1881. G. F. B. 
_ 2. Simple Dissociation Apparatus.—Tommast has described a 
‘imple apparatus which he called a dissocioscope, for showing the 
dissociation of ammoniacal salts. It consists of a tube of glass 
~0 to 25 centimeters long and 3 or 4 centimeters in diameter. By 
means of a platinum wire a slip of blue litmus paper, previously 
moistened with a solution of ammonium chloride, is suspended in — 
the tube. The solution should be exactly neutral and be com- 
i 
and the paper becomes blue again. is may be repeated any 
number of times at pleasure. Of course by using the bromide, 
