about the form of equilibrium now continues, and the ring advances, its form rapidly changing in the manner which the View P beautifully reveals.
The inquiry naturally arises, Would two rings existing under similar circumstances, in a perfect fluid, or in the luminiferous ether, join together? If two vortices can unite, then would not these in turn join with others? If such be the case for perfect fluids, then it follows that a system of electrons or atoms constituted of vortices, in a perfect fluid, would not preserve their identity, but would form unions which would ultimately destroy any distinctive existence which the vortex atoms or electrons might possess.
These are questions upon which further experimentation would throw much light and the experimental facts obtained would constitute a proper basis for, and check upon, mathematical investigations regarding perfect fluids.
The above-described experiments were begun at the laboratory of The Leeds and Northrup Company, Philadelphia, Pa., in April, 19o9, and were later carried on and completed in January, 191I, at the Palmer Physical Laboratory, Princeton, N.J. When working at the first-mentioned place, the writer was ably assisted by Mr. William Wrighton, in charge of the experimental work of The Leeds and Northrup Company, who spent much time on the research