SULPHURIC ACID AND WATER. 295 
which an equal weight of water would be raised 
by the heat required to raise the compound 189°. 
These due calculations being made, it is evident 
that the greatest quantity of heat 7s evolved in the 
instance when the greatest diminution of specific 
heat takes place; but, the amounts of diminution 
do not bear a direct ratio upon the quantities of 
heat evolved: yet, I think, it cannot but be con- 
cluded that the heat evolved and the rise of 
temperature produced, when oil of vitriol and 
water are mixed, are consequences of diminution 
of specific heat. 
The circumstance of the quantities of heat 
evolved not being in direct proportion to the 
diminutions of specific heat, is opposed to the 
notion that the specific heats of bodies express 
the ratios of the total quantities of heat which 
bodies contain. 
From the evidence furnished by my few expe- 
riments, it appears that the differences between 
the quantities of heat evolved, in the several 
instances, have a nearly geometrical ratio upon 
each other, speaking relatively to the differences 
between the diminutions of specific heat in the 
