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something. The probabilities are, however, enormously in 
favour of the theory that ascribes certain properties to ether, and 
that light and heat consist in its undulations. All known 
facts coincide absolutely with this theory, and it has been the 
means of leading physicists and mathematicians to fresh 
discoveries. 
What is this ether, that it possesses properties so extraordi- 
nary, and that, to speak in common language, a mere nothing 
of it in point of quantity can be the source or the vehicle of 
enormous powers ? Professor Tyndall says it must be a material 
substance, but perhaps not a form of ordinary matter. If it is 
composed like common matter, its particles or molecules 
do not touch ; and in that case it will be difficult to avoid the 
belief that there is a still more subtle kind of matter filling up 
the interspaces. If it be matter not divided into atoms or 
molecules, but continuous, we may expect to find that it will 
exhibit many properties and peculiarities not yet discovered, 
differentiating it from matter in ordinary forms. 
Faraday followed Newton in feeling an invincible objection 
to the notion that matter could act through empty spaces, and, 
as we find in his life by Dr. Bence Jones, he was fond of quoting 
the following passage from a letter of Newton to Bentley : — 
“ That gravity should be innate, inherent, and essential to 
matter, so that one body may act upon another at a distance 
through a vacuum , and without the mediation of any tiling 
else, by and through which this action and force may be 
conveyed from one to another is to me so great an absurdity, 
that I believe no man who has, in philosophical matters, a 
competent faculty of thinking, can ever fall into it. Gravity 
must be caused by an agent acting constantly according to 
certain law T s ; but whether this agent be material or immaterial, 
I have left to the consideration of my readers.” 
Faraday’s own views on this subject were never very clear to 
other people. He recognised “ lines of force,” and spoke of 
“ atoms ” as centres of force, and not as so many little bodies 
surrounded by forces. The force was the atom extending 
indefinitely in all directions. According to these conceptions, 
“ water is not two particles of oxygen (and hydrogen) side by 
side, but two spheres of power mutually penetrated, the centres 
even coinciding.” * In the same place he said, “ The force or 
forces constitute matter ; there is no space between the particles 
distinct from the particles of matter.” 
We need not for present purposes pursue these speculations 
further. The wave forces mentioned communicate immense 
velocities to the molecules of matter, and these velocities are, in 
• “Life of Faraday,” vol. ii. p. 178. 
