64 VIBRATIONS CONVERGED BY LENSES, ETC. 



after noticed. The elastic vibrations of the air 

 and electric ether are thus shown to correspond. 

 To converge the vibrations of the air, as sounds, 

 more forcibly against the tympanum of the ear, 

 ear-trumpets are used. 



Concave arched surfaces of domes also reflect 

 the vibrations of sounds. 



To concentrate the vibrations of the electric 

 ether, as light, more powerfully on the retina of 

 the eye, the converging lenses of telescopes and 

 concave reflectors are used. The same elec- 

 tro-mechanical action that is transmitted to the 

 eye as light, might serve for a telegraphic com- 

 munication from the sun, or even from the great 

 star Sirius, if a thermoscope were placed at the 

 aperture of the telescope where the eye is usually 

 adjusted. The light would produce movements 

 of a magnetic needle, similar to those employed 

 in Wheatstone's telegraph for transmitting signals 

 across the ocean. 



The electric ether partakes of the passive char- 

 acter of all matter in its incapability to stop itself 

 when put in motion. Light and sound are per- 

 petually transmitted. The continuous progression 

 of light through infinite space is graphically illus- 

 trated by an astronomer, who says: " In adjust- 

 ing my telescope, during the day, toward a remote 

 hillside, I beheld some boys robbing an orchard. 

 If that robbery had been committed on a remote 

 star, and had my telescope been sufficiently per- 



