214 HOLTZMANN ON THE HEAT AND ELASTICITY 
In most cases - may be neglected in comparison with = , it 
A 
then becomes more simple, 
W.a= fide + C, 
g 
or DW .@ =k (1 +-ad)+.Cy . .0) a eye a2.) 
37. The quantity of heat which is required to overcome the 
cohesion results from 
Sisatgee hd + at) 
a a 
According to the assumption made in No. 15, if, at the same 
time, it be admitted that the specific heat of the liquid be con- 
stant and = s, we have 
w= WW — St, 
where wy is the latent heat of the vapour of the temperature 
t=0. We then have 
Cr. k(1+ at) 
ee Gee OE Se eae a 1) smaee, ee) 
The heat which destroys the cohesion of the liquid conse- 
quently decreases with the temperature. 
For water, w)= 640, according to Brix, if we set out from 0° C.; 
= Fe = 0'1394 (No. 20) ; + = 236 (No. 17). 
Consequently the heat requisite for the suspension of the co- 
hesion of water, or the cohesion of water itself, is 
640 — ¢ — 0°1394 (236 + #) = 607 —1°1394.%. . (4.) 
The action of this quantity of heat is lost in all steam-engines, 
which hitherto has been wholly overlooked ; this loss amounts, 
as is evident, to much less at high temperatures than at low 
ones, whence it results that attention must be directed far more 
than hitherto to the construction of steam-engines with very high 
pressure. 
The quantity of heat required, according to formula (4.), for 
the overcoming of the cohesion of steam amounts for 1 kilogram. 
water with 
@#=, Q 100° 200° 400° 533° 
tp = 607 493 379 151 0 
units of heat. 
38. Of the 640 units of heat required for the production of 1 
kilogram. steam, ¢ of them are required to heat the water, and 
only 33 + 0°1394.¢ 
