Mr Taylor, Experiments with Rotating Fluids 329 



Preliminary experiments made with a pair of concentric 

 cylinders which are both of them capable of being rotated, show 

 that the Rayleigh condition appears to be verified for high speed 

 rotation, but that at low speed it is very considerably modified, 

 presumably by viscosity, the motion being stable beyond the 

 hmits prescribed by the Rayleigh theory. 



Calculations of the effect of viscosity on the stabihty of sym- 

 metrical disturbances are very difficult, but an equation has been 

 obtained which can probably be solved graphically ; and the author 

 hopes shortly to be able to say whether viscosity should increase 

 or decrease the stabihty of symmetrical disturbances. 



