512 ON THE EXPLOSION OF THE BOILER 
revolve, in a given time; the weight and dimen- 
sions of the Locomotive Engine being given, the 
pressure of the steam, on the boiler, at the be- 
ginning and end of the time, being known, and 
the pressure of the atmosphere on the top of the 
fire-box being neglected; and it being supposed 
that the Engine will continue to revolve about the 
same axis passing through its center of gravity. 
Let w=154 tons=555520 ounces=the weight 
of the Locomotive Engine. 
Let it be supposed, that the whole Locomotive Engine, con- 
sisting of boiler, wheels, &c., is a parallelopipedon, whose 
length is 12 feet, and depth 6 feet ; then, the distance of the 
centre of gyration, from the centre of gravity of the Engine, is 
/ 15 feet ; and if the pressure of the steam, from the aperture, 
on the top of the fire-box, be supposed to act upon the inside 
of the top of the boiler, at the mean distance of a foot from 
the end of the boiler, then =i 
is the weight, which must be 
placed, at one foot from the end of the boiler, in the line which 
passes, longitudinally, through the centre of gravity of the 
Engine, so that, when this weight revolves about the centre of 
gravity of the Engine, its inertia may be the same as that of 
the Locomotive Engine. 
Let b=5 feet=the perpendicular from the centre of gravity 
of the Locomotive Engine, upon the direction, in which the 
ee 
