and on Astronomical Refractions, 
565 
Tra{\K = pa{l-\-c) — p' a {V + 
c) 
for the values of the constants E, y. See p. 511. 
To this must be added the work effected during the course of the 
piston through l\ which is p^ a /, and if R is the total pressure ex- 
erted upon unity of surface of the piston 
pa{l-^c)— p^ac 
+ a{f -\-c) [p^y -Ep') 
= aRl 
y 
^(r-i) 
iog-< 
1 -Ep~ 
1 J 
(A)^ 
R — (1 + S) r+ y' the friction of the machine not loaded, 
8 the increase of this friction due to unity of the charge r, ja" the 
pressure on the surface of the piston, representing the atmospheric 
pressure when the machine works without condensation, and other- 
wise the pressure of condensation in the cylinder. 
If S denote the volume of water converted into vapour by the 
boiler in unity of time, this volume in the cylinder becomes 
SK 
A. 
p' Y --E p' 
K being the same constant as in p. 563. 
It is evident, according to the reasoning of M. de Pambour, in 
p. 125. of his work, that if v denote the velocity of the piston 
SK V + c 

p'y-Ep' 
(B.) 
* This equation is equivalent to the equation (A) of M. de Pambour. p. 123 which 
may be put into the form ^ * »>***»-i* 
pa{l-^c) - p'ac -}- Nap. log = a ni. 
or pa (I-}- c) - - p'ac + [6*9505960] ^ log | 
the pressure being reckoned in lbs. per square inch. 
