the Weight ascribed to Heat. 183 
further investigations relative to this subject, it may not be amiss 
to mention the method I pursued for discovering whether the 
appearances mentioned in the foregoing experiments might not 
arise from the imperfections of my balance; and it may likewise 
be proper to give an account, in this place, of an intermediate 
experiment which I made, with a view to discover, by a shorter 
route, and in a manner less exceptionable than that above 
mentioned, whether bodies actually lose, or acquire, any weight, 
upon acquiring an additional quantity of latent heat. 
My suspicions respecting the accuracy of the balance arose 
from a knowledge, — which I acquired from the maker of it, — 
of the manner in which it was constructed. 
The three principal points of the balance having been deter- 
mined, as nearly as possible, by measurement, the axes of 
motion were firmly fixed in their places, in a right line, and 
the beam being afterwards finished, and its two arms brought 
to be in equilibrio, the balance was proved by suspending 
weights, which before were known to be exactly equal, to the 
ends of its arms. 
If with these weights the balance remained in equilibrio, it 
was considered as a proof that the beam was just ; but, if one 
arm was found to preponderate, the other was gradually 
lengthened, by beating it upon an anvil, until the difference of 
the lengths of the arms was reduced to nothing, or until equal 
weights, suspended to the two arms, remained in equilibrio; care 
being taken, before each trial, to bring the two ends of the 
beam to be in equilibrio, by reducing, with the file, the arm 
which had been lengthened. 
Though, in this method of constructing balances, the most 
perfect equality in the lengths of the arms may be obtained, 
B b 2 
