342 
Froceedings of the Royal Irish Academy. 
wonld be if tlie vortices were arranged so as to give absolutely steady 
motion for the equilibrium condition of the medium. 
" I have been anxiously considering the effect of free vortex rings 
with vacuous cores among the vortex columns of this tensile vortex 
ether, as suggested for cored vortices at the end of your communication 
of April 26, 1889, to Nature. It will be an exceedingly interesting 
dynamical question ; though it seems to promise at present but little 
towards explaining universal gravitation or any other property of 
matter ; so you may imagine I do not see much hope for chemistry 
and electro-magnetism." 
