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When the emissory or corpuscular theory of light had to be abandoned a medium for light's interplay between worlds had to be conceived. The existence of an all-pervasive medium called the luminiferous ether was launched as a theory. Its reality has been so far demonstrated that but very few doubters remain. What facts of its conditions and powers can be known?
"In 1882, Professor Lodge, in a lecture before the Royal Institution on 'The Luminiferous Ether' defined it as: "'One continuous substance, filling all space, which can vibrate as light, which can be sheared into positive and negative electricity, which in whirls constitutes matter, and which transmits by continuity and not impact every action and reaction of which matter is capable.
His body turned in space at times, and he saw the spreading cone of luminous gas behind them like the wake of a great ship in a phosphorescent sea. The hiss and threshing of many wings came unceasingly. Once he swung close to another body clad like his own and, like him, enmeshed in a net. And he saw in the light of the luminiferous air the girl's wide, staring eyes.
Mere space cannot act as matter acts, even though the utmost latitude be allowed to the hypothesis of an ether; and admitting that hypothesis, it would be a large additional assumption to suppose that the lines of magnetic force are vibrations carried on by it, whilst as yet we have no proof that time is required for their propagation, or in what respect they may, in general character, assimilate to or differ from their respective lines of gravitating, luminiferous, or electric forces.
By as much as the intensely-heated gases of the interior are disabled by the dissociation of their molecules from giving off luminiferous undulations, by so much must they be disabled from absorbing the light transmitted through them.
When the wire approaches the magnet, an action is evoked within it, which travels through it with a velocity comparable to that of light. One substance only in the universe has been hitherto proved competent to transmit power at this velocity; the luminiferous ether.
But about 1818 the experiments of Fresnel and Arago with polarization of light made it seem very doubtful whether the theory of longitudinal vibrations is sufficient, and it was suggested by Young, and independently conceived and demonstrated by Fresnel, that the luminiferous undulations are not longitudinal, but transverse; and all the more recent experiments have tended to confirm this view.
The purpose to which the phraseology of Properties and Powers is specially adapted, is the expression of this sort of cases. Thus we distinguish the attractive or gravitative property of the earth, and its magnetic property: the gravitative, luminiferous, and calorific properties of the sun: the color, shape, weight, and hardness of a crystal.
It would be such a vacuum as cannot be artificially produced; for if we pump the air from a receiver there remains the luminiferous ether. Through one of these cavities light could not pass, for there would be nothing to bear it. Sound could not come from it; nothing could be felt in it. It would not have a single one of the conditions necessary to the action of any of our senses.
He invested the space through which they run with a kind of materiality; and the probability is that the progress of science, by connecting the phenomena of magnetism with the luminiferous ether, will prove these 'lines of force, as Faraday loved to call them, to represent a condition of this mysterious substratum of all radiant action.
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