REPORT ON OPTICS. 
315 
grave, their names will be indissolubly embalmed in the sym¬ 
pathies of their countrymen ; and in recounting their brilliant 
discoveries, the philosophers of every age will mingle their tears 
with their admiration. 
. Heu fortunati ambo ! 
Nulla dies unquam memori vos eximet eevo. 
As the discoveries of Fresnel and his contemporaries have 
been fully described in several works in our own language, it 
would be an unprofitable task to give any account of them at 
present. The nature of this Report, however, requires me to 
notice those more recent discoveries which are less accessible 
and less generally diffused ; and to endeavour to point out those 
new paths of discovery which the young philosopher may most 
successfully pursue, and those applications of optical science 
which are likely to be most useful in extending the power of man, 
in throwing light upon other branches of knowledge, and in in¬ 
vestigating the structure and properties of organized matter. 
I regret that the first part of this task should embrace the 
researches of so few labourers ; and I fear that the future holds 
out but little prospect of any increase either in their number or 
in their efficiency. Pursuits more popular and more generally 
appreciable, and employments incompatible with scientific in¬ 
quiry, have allured from Optical research many of those di¬ 
stinguished individuals who were most able to grapple with its 
difficulties ; and within these few months Science has lost Dr. 
Seebeck* of Berlin, one of the most able and successful dis¬ 
coverers of the present century. 
The only individuals who have been recently and actively 
engaged in the higher departments of physical optics, are Mr. 
Airy of Cambridge, and M. Cauchy of the Academy of Sci¬ 
ences. 
In examining the two rays produced by the double refraction 
of quartz, Mr. Airy was led to a discovery which we consider 
as one of the most important in its results, and one of the most 
beautiful in its phenomena that has yet been made in this 
branch of optics. The circular polarization of the two rays along 
the axis of quartz had been studied by different philosophers, 
and had been explained by Fresnel with singular ingenuity on 
the principles of the undulatory theory. No attempt, however, 
had been made to account for the existence of this property 
only in the rays which pass near the axis of the crystal, or to 
define the limit where the circular polarization ended and the 
* Dr. Thomas John Seebeck was born at Reval on the 9th of April 1770. 
He died at Berlin on the 10th of December 1831, in the 62nd year of his age. 
