201 
steam is converted into water, is equally the obvious conse- 
quence of the change. Such reciprocal changes of the 
constituent forms of bodies, clearly serve to explain the 
% 
changes of heat into its latent and sensible forms, as before 
stated. We find too, all solids show the gradual loss and 
gain of heat, however high the temperature may be raised, 
unless the body itself be converted into a liquid or vapour, 
and then the sudden absorption of latent heat in them is 
found, as in the case of steam from water. Taking the 
total amount of sensible heat in steam of 501bs. pressure 
(as in common use) at 281°, as above shown, and the latent 
heat in the same steam, as given in the tables, at 2,670°, the 
total absolute heat in such steam will equal 2,951 degrees 
Fahr. Now, if the entire heat so contained in steam of 
501bs. pressure, were to remain thermometric heat, it would 
of course raise the temperature of the pipes and engine to 
the same degree, which would soften the metal and destroy 
the vessels conducting it, to say nothing of the danger of 
attending or even approaching the engine. I am aware 
of the allegation, that heat, not appearing sensible in steam 
beyond the boiling point, is “ because of the expansion of 
water into some 1,640 times its liquid bulk when converted 
into steam.” Well, even though we allow this way of 
accounting for the insensible state of the heat in steam, still 
the fact remains that the 934*6° of heat exists in the steam, 
for that amount is carried over by it to the condensor, and 
. reappears as sensible heat in the water. 
From these facts it would seem that the term “ latent 
heat” is the only matter in question ; for the entire amount 
of heat, say of 934°, that disappears as sensible heat in the 
steam, reappears sensible in the condensor. It is quite 
