On the Power of Fluids to conduct Heat, 393 
experiment, and consequently are not purely 
hypothetical: those expressing the other effect, 
except 42° and 192°, are put down hypotheti- 
cally, aa the law of ma Sie has not been 
ascertained. 
It is to be supposed, that a given quantity 
of water, of the several temperatures mentioned, 
is carefully poured upon a cake of ice at the 
bottom of a cylindrical glass jar, and stands 
Without agitation for a given time, as half an 
hour; then the proportionate quantity of ice 
supposed to be melted by the two causes se- 
parately are stated in numbers, and then the 
sums are taken to express the joint effects. 
