4 
From the triangle Obc (Fig. 2) we get 
dv _ sin e 
dt sin 8 
( 4 ) 
Fig. 2. 
We proceed to find the relation between ~ and the principal linear 
moment K of the impressed forces. 
Fig. 3. 
From Analytical Mechanics,* the principal moment On= Gr (Fig. 3) 
of all the quantities of motion of a solid body taken relatively to 0 ; and 
if drawn from 0 , moves about 0, so that the velocity of its end is 
constantly equal and parallel to the length K . 
'Professor Bobilef “ Course of Analytical Mechanics,” pp. 454-456. 
Resal “ Traite de Mecanique general, 1873,” p. 247, Vol. 1, 
