560 ON A NEW METHOD FOR ASCERTAINING 
method in their researches on specific heat; and, 
by the invention of the calorimeter, carried it to 
the greatest degree of perfection of which it is 
in all probability capable. In practice, however, 
this method has been found exceedingly clumsy 
and tedious, and liable to a variety of errors 
which have been pointed out by Wedgewood. 
It has, in consequence, been long ago abandoned 
by accurate experimenters. 
The method of mixtures has been employed 
by Boerhaave, Black, Irvine, Wilcke, Crawford, 
and others. In this method, the heat lost by one 
body in cooling, is received by another body 
which is heated. By knowing the weights of the 
bodies, and the temperatures gained and lost by 
them, it is easy to deduce the relation of their 
specific heats. 
The method of cooling was employed by Meyer, 
Leslie, and Dalton, and has been much improved 
by Dulong and Petit. It consists in ascertaining 
the rapidity with which different bodies cool, 
when placed in similar circumstances with respect 
to the radiation of heat. 
The methods of cooling, and especially of mix- 
