206 
by such intangible, unknown, and suppositious molecules, or 
ultimate particles of bodies. And to base mathematical for- 
mulse on such visionary forces and motions can hardly com- 
port with the dignity of the exact sciences, or tend to shed 
any light upon physical truths, which after all must be sus- 
tained by known facts, rather than by theories, old or new. 
As these two theories are based on opposite principles, they 
cannot both be true ; and without referring here to any of 
the other cases (adduced in former papers) that appear to 
prove the untenable nature of the new theory, I conclude 
by submitting the above short outlines of the phenomena 
resting on, and explaining, the doctrine of latent heat. 
