MancJiester Memoirs^ Vol. Iv. (1911), No. X \y 



{c) A non-homogeneous body of the same size, shape 

 and weight as a homogeneous body, shows a 

 lesser tendency to approach the centre. If the 

 centre of gravity of the non-homogeneous body 

 is sufficiently low, the body works out to the 

 outer edge of the vortex. 



{i£) The shape of the plane of flotation (round, square 

 or rectangular) has no effect on the behaviour of 

 the object. This is, however, only true so Ion"- as 

 the vortex is a true forced vortex, i.e., has the 

 velocity everywhere proportional to the radius. 

 Any acceleration or retardation of the whirlino- 

 table, and hence of the containing vessel, caused 

 a sensible modification of several of the pheno- 

 mena. 



{e) In similar homogeneous bodies of the same specific 

 gravity the smaller appear to show the greater 

 tendency to approach the centre, although this 

 effect is not strongly marked. 



§ 5. The forces called into play in a forced vortex, 

 while of the same general kind as in the free vortex, differ 

 in relative magnitude, and, in some cases, in way of action 

 owing to the fact that the velocity of whirl now increases 

 with the radius, varying directly as the distance from the 

 centre. A further difference follows from the fact that 

 the fluid now moves in a series of concentric circles 

 instead of in equiangular spirals. 



Thus, due to the pressure of the surrounding vortex, 

 apart from any consideration of the position of the centre 

 of gravity of the body, the latter would tend to remain in 

 equilibrium at any radius, with no tendency to approach 

 or recede from the centre. 



