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motion, than an iEolian harp analyses sound, or the air in 
motion, for light and sound are both merely modes of motion 
of two different elements. 
As a magnet conveys motions of one kind, so glass con- 
veys motions of another, the one not more wonderful than 
the other. 
We surely consider the molecules of the magnet to vibrate. 
Why not the molecules of glass, and consequently of all 
matter refracting light ? 
A telescope is but another kind of telegraph, only much 
more comprehensive in its range. 
