42 R. Clausius on the Application of the 
and at this last to convert a kilogram into steam, soem quantity 
of heat may be calculated from the data already gi 
59. In conclusion, I must add yet a few wordnic on ithe friction, 
- in which however I will confine myself to justifying my course in 
leaving the friction entirely disregarded in the equations hitherto 
developed, by showing that instead of introducing the friction 
oy em aa harmony expressions for the work as Pambour has 
bring it into calculation, according to the same 
peineinlen ‘sdbacxjachaly. which in fact has been done in the same 
manner also by other writers. 
The forces which the machine has to overcome, when in action, 
may be distinguished _. se following manner. 1. The resist- 
pi which is op + from without, and the overcoming 
which forms the vsefil igre required of it. Pambour calls 
this resistance the load (charge) of the machine. 2. The resist- 
ances which have their origin in the machine itself, so that the 
friction, although besides the friction, in the more narrow sense, 
other forces occur among them, particularly ¢ the resistances of 
the pumps belonging to the steam engine, with the exception of 
the one which feeds ' = 2 and wach has already been con- 
sidered in what prec 
Pambour fe ‘ais calculation both kinds of resistances 
as forces which are opposed to the motion of the piston; and in 
order to be able to unite them conveniently with the pressure- 
forces of the steam upon both sides of the piston, he selects the 
notation in the same manner as this is done for the pressure of 
the steam, namely, so that the symbol does not signify the whole 
force, but ‘the whole portion of it which comes upon the unit of 
- surface of the piston. Let the letter R denote the load in this 
sense. 
A. still further distinction must be made in the case of the 
friction, The friction, namely, has not a constant value for every 
machine, but increases with the load. Pambour decomposes it 
therefore into two parts, that which is already present when the 
machine moves without load, and that which is first added by 
the load. With respect to the last, he assumes that it is propor- 
tional to the load. He accordingly expresses the friction ietarrda 
to the unit of surface by 
f+S.R, 
in which f and 4 are quantities which, it is true, depend upon 
e sae and dimensions of the machine, but which ac- 
cording to vues are to be considered as constant for a par- 
ticular dil 
We may nb refer the work of the machine, instead, as here- 
tofore, to the moving force of the steam, to these resisting forces, 
\ 
ieee Se) 
i alieags RE es Ra h se Tt 
