POLARIZATION. 217 
ther, it is not only on account of its singularity that this 
theory ought to command the attention of the physicist ; 
Fresnel found it the key to all the beautiful phenomena 
of colours, which are produced in plates of crystal pos- 
sessing double refraction ; he analyzed them in all their 
details; he determined their most hidden laws; he 
proved that they were only particular cases of inter- 
ferences. He thus overturned from their base many 
scientific romances to which these phenomena had given 
birth, and which had secured more than one _pros- 
elyte, whether by their striking nature or the distin- 
guished merit of their authors. In a word, here, as in 
every branch of science which is advancing towards per- 
fection, the facts have seemed complicated only because 
we examined them at too near a distance and with too 
microscopic a view; but at the same time, by a more 
enlarged ‘conception, their causes have been found to be 
more simple than we might have expected. 
POLARIZATION. 
Although I am aware at what point we risk tiring even 
the most kindly disposed audience when we speak long 
at right angles to each other they could not. It only required then 
the action of the analyzer (A) to resolve each vibration again into 
A 
ee — 4 
7 <3: - 
ft 
lh 
two, at right angles, of which two sets in a plane perpendicular to 
that of analyzation are suppressed; and two in that plane transmit- 
ted; and which, consequently, being in parallel planes, are able to 
give interference, and produce the observed coloured tints. 
SEC. SER. 10 
