Chap. IT.] INERTION. 19 



momentum which has been generated by that motion 

 tends to carry the point A round the axis in the di- 

 rection A H B L ; the momentum generated at the point 

 B tending at the same time to carry the point b 

 round the axis in the opposite direction, that is, in 

 the direction b H A L. The forces generated on the 

 sides A and b are thus brought into conflict : the 

 lesser force, b, must of necessity yield more or less, 

 in accordance with the relation which the opposing 

 forces bear to each other : and thus the greater force 

 of the side A imparts a motion of rotation to the 

 globe in the direction a h b l. 



Also : since in streams of water the greatest force 

 is in the central parts of the streams ; therefore, 

 wherever a stream is obstructed, the greater force of 

 the central part of the stream overwhelms the lesser 

 forces on each side ; so that the stream divides, 

 branching off right and left from the point of ob- 

 struction. 



And for the same reason, also, when two streams 

 meet, there must be offsets branching off in opposite 

 directions from the meeting-points. 



In the case of the overwhelming of lesser forces 

 by greater forces, exemplified above in connection 

 with Plate JIL, the check to the onward motion is 

 given at the central axis ; so that the quantities of 

 motion brought into conflict areof necessity unequal ; 

 for the masses of matter brought into conflict may, 



c 2 



