OF THE IRK, LOCOMOTIVE ENGINE. 513 
pressure of the steam acts upon the inner surface of the 
top of the boiler. 
u=the velocity, with which the point, at the distance of one 
foot from the end of the boiler, revolves about an axis 
passing through the centre of gravity of the Engine, at 
the time, ¢. 
§=the angle, to radius unity, through which the Engine has 
revolved about the axis passing through its centre of 
gravity, in the time, ¢. 
Then, retaining the notation in the last article. 
11d ; 
ap = “~~ = the pressure on the inner surface of the top of 
A 
the boiler; and ce = the moving force of the steam, by 
which the Locomotive Engine is made to revolve about its 
centre of gravity; and, therefore, = = the accelerating 
force. 
5gabiid Oscar ' _ Sgatl _ 
Hence aaa dt = du; or, putting »= aaa oe 62.5 
nearly. 
biidt=du; 
but, by Art. 9, 3=De™ * ‘and therefore, 
bDe “dt=du. 
Pee) nay 
By Integration, oT ae eee and, when u=o, t=o; 
bD — pt bd 
therefore pa —e )=u=—73 
