Knowledge of the Ancients. 267 
“ The moifture, fays Ariftotle, that is about the 
earth, being converted into vapours by the rays 
of the fun, afcends. When it has arifen, the heat, 
by whofe afliftance it had afcended, leaves the 
vapour (or, as Dr. Black would fay, becomes 
fenfible) and then, the vapour again affumes a 
confidence, and, from being in the form of air, 
becomes water. Meteorol. L. I. C. 9. 
<c The reafon, fays Ariftotle, why dew and hoar 
froft do not concrete in elevated fituations, is, 
that in them the air is much agitated, which 
diftblves* the confidence of the water. Ibidem. 
Cap. 10. 
Dr. Black’s dofrrine of Latent Heat, feems not 
to have been altogether unknown to the ancients. 
“ Snow, fays Ariftotle, cannot be formed, with¬ 
out the cold prevails, much heat dill remaining 
in it. For in a cloud, or vapour, there is much 
heat which remains of that fire, that has abforbed 
the moifture from the earth.” Ariftotle here 
mentions, that heat or fire was dill contained in 
the cloud or vapour, and fo far is agreeable to 
Dr. Black’s fyftem ; but the latter difeovered, that 
when the condenfation took place, the heat, before 
latent, then became fenfible. 
* O; JiaXfji rriii Toia.vTr,v GVtrxaiy. 
hL B. Evrac-t; means the confidence, or folid form of 
any thing, in its primary fignification, and i§ often applied 
Jo water. Vide fiex. Budiei. Vox Svfec-1? 
IV. The 
