340 MR. FARADAY ON THE FORMS AND STATES OF FLUIDS, &c. 
were hardly sensible ; and something analogous to this may take place in the 
atmosphere. If so, it would seem likely that these vibrations occurring con- 
jointly with those producing sound, would have an important influence upon 
its production and qualities, upon its apparent direction, and many other of 
its phenomena. 
1*28. Then by analogy these views extend to the undulatory theory of light, 
and especially to that theory as modified by M. Fresnel. That philosopher, in 
his profound investigations of the phenomena of light, especially when polar- 
ized, has conceived it necessary to admit that the vibrations of the ether take 
place transversely to the ray of light, or to the direction of the wave causing 
its phenomena. “ In fact we may conceive direct light to be an assemblage, 
or rather a rapid succession, of an infinity of systems of waves polarized 
(i. e. vibrating transversely) in all azimuths, and so that there is as much 
polarized light in any one plane as in a plane perpendicular to it.” IIerschel 
says that Fresnel supposes the eye to be affected only by such vibrating 
motions of the ethereal molecules as are performed in planes perpendicular 
to the direction of the rays. Now the effects in question seem to indicate 
how the direct vibration of the luminous body may communicate transversal 
vibration in every azimuth to the molecules of the ether, and so account for 
that condition of it which is required to explain the phenomena. 
129. When the star of ridges formed by a vibrating cylinder (119) upon the 
surface of water is witnessed instead of the series of circular waves that might 
be expected, it seems like the instant production of the phenomena of radia- 
tion by means of vibratory action. Whether the contiguous rarified and con- 
densed portions which I have supposed in air, gases, vapour and the ether, are 
arranged radially like the ridges in the experiment just quoted, or whether 
rare and dense alternate in the direction of the radii as well as laterally, is a 
question which may perhaps deserve investigation by experiment or calcu- 
lation. 
Royal Institution, 
July 3C )th, 1831. 
