THE HAMILTON ASSOCIATION. 
les 
APPLICATION OF KELVIN’S THEORY OF THE 
ETHER TO THE STELLAR UNIVERSE. 
Read before the Astronomical Section of the Hamilton 
Scientific Association. 
BY J. R. COLLINS, TORONTO. 
Certain experiments with light, electricity and magnetism 
show that these forms of energy are conveyed to us from their 
source through a medium by a vibratory and rotary wave mo- 
tion. The vibrations, being across the line of propagation, are 
similar to those that occurred in a solid, as when a stretched 
cord is vibrated at one end and an undulating wave is made to 
travel up and down its length. The speed of the wave de- 
pends on the tension of the cord, the greater the tension the 
greater the speed of the wave. In the strongest steel a vibra- 
tory wave might be made to travel at a speed of several miles 
per second, but light waves, it can be shown, travel at the rate 
of 186,000 miles a second. If tension were increased in this 
way sufficiently to cause a vibration to travel with anything like 
the velocity of light it would be necessary to suppose that we 
were dealing with a substance or medium capable of sustaining 
strains and stresses thousands of times greater than the strong- 
est steel can support. As no material substance can sustain 
such a strain, we must, for this and other reasons, suppose that 
a subtle medium not only fills intersteller space but saturates all 
material things as well, this subtle medium being termed ether. 
The former theories that had led up to the vortex theory were 
reviewed and an outline of Kelvin’s views of vortices was pre- 
sented. Kelvin started by supposing the space of the universe 
(whether limited in extent or infinite) to be filled with a con- 
tinuous perfect fluid, structureless and without parts, being a 
single unit and endowed with a property of inertia. If minute 
vortices, in the form of rings, were once set up in this medium, 
