2 FRAGMENTS OF SCIENCE. 
vague or fanciful conception on the part of scientific men. 
Of its reality most of them are as convinced as they are of 
the existence of the sun and moon. The luminiferous 
ether has definite mechanical properties. It is almost 
infinitely more attenuated than any known gas, but its 
properties are those of a solid rather than of a gas. It 
resembles jelly rather than air. This was not the first 
conception of the ether, but it is that forced upon us by a 
more complete knowledge of its phenomena. A body thus 
constituted may have its boundaries; but although the ether 
may not be co-extensive with space, it must at all events 
extend as far as the most distant visible stars. In_fact it 
is the vehicle of their light, and without it they could not 
be seen. This all-prevading substance takes up their mo- 
lecular tremors, and conveys them with inconceivable 
rapidity to our organs of vision. It is the transported 
shiver of bodies countless millions of miles distant, which 
translates itself in human consciousness into the splendor 
of the firmament at night. 
If the ether have a boundary, masses of ponderable 
matter might be conceived to *exist beyond it, but they 
could emit no light. Beyond the ether dark suns might 
burn; there, under proper conditions, combustion might 
be carried on; fuel might consume unseen, and metals be 
fused in invisible fires. A body, moreover, once heated 
there, would continue forever heated; a sun or planet once 
molten, would continue forever molten. For, the loss of 
heat being simply the abstraction of molecular motion bv 
the ether, where this medium is absent no cooling could 
occur. A sentient being, on approaching a heated body 
in this region, would be conscious of no augmentation of 
temperature. The gradations of warmth dependent on 
the laws of radiation would not exist, and actual contact 
would first reveal the heat of an extra ethereal sun. 
Imagine a paddle-wheel placed in water and caused to 
rotate. From it, as a center, waves would issue in all 
directions, and a wader as he approached the place of dis- 
turbance would be met by stronger and stronger waves. 
This gradual augmentation of the impression made upon 
the wader is exactly analogous to the augmentation of 
light when we approach a luminous source. In the one 
case, however, the coarse common nerves of the body 
suffice; for the other we must have the finer optic nerve. 
