464 PROCEEDINGS OF THE AMERICAN ACADEMY 



theories stand or fall according to the quantity as well as the quality of 

 the forces which they furnish for the explanation of phenomena, — 

 quantities which the highest mathematics are often inadequate to calcu- 

 late. 



Herschel moved from Cambridge to London, and began the 

 study of Law. But the new acquaintance which he formed with 

 Wollaston, the microscopic philosopher, as he has been called, soon 

 turned his attention to Chemistry and Optics. His first publica- 

 tion in chemistry, on hyposulphurous acid, contained an important 

 discovery, and was followed, at various intervals, by others, — on 

 photography, on the chemical influence of light, on the action of light 

 on precipitation, and on its effect upon vegetable colors. His inves- 

 tigations in Optics began at as early a date, and were not wholly re- 

 linquished until 1863. He applied the theory of diffraction to the ex- 

 planation of the beautiful colors of mother-of-pearl; calculated the 

 colored curves, called lemniscates, produced by the passage of polarized 

 light through biaxial crystals ; investigated Newton's tints ; studied the 

 aberration of lenses, the absorption of light by colored media, the light 

 emitted by lime, the mineralogical import of right-handed and left- 

 handed circular polarization in quartz, the irregularities of the colored 

 rings in apophillite, the insensibility of some eyes to certain colors ; 

 discussed the merits of a fluid lens for the telescope ; examined the 

 coloring matter in certain green sands ; suggested improvements in the 

 Argand lamp ; added the lavender tint to the solar spectrum ; and finally, 

 by his announcement of epipolic dispersion as exhibited on the surface 

 of sulphate of quinine, furnished Stokes with the key to his important 

 discovery of the change which luminous waves may suffer in their 

 period of oscillation. 



Notwithstanding the numerous successes which Herschel achieved as 

 mathematician, chemist, and physicist, and the still greater triumphs in 

 these directions of which he gave promise, he was destined by circum- 

 stances, if not by preference, to be an astronomer. The Royal Astro- 

 nomical Society of London was founded in 1820, with William Herschel 

 as its first President, and John Herschel as its first Foreign Secretary, 

 and in the thirty-eight volumes of valuable memoirs which it has pub- 

 lished, no other name shines so brightly as that of Herschel. If the il- 

 lustrious F. G. W. Struve was animated, as he confesses, by the great 

 example of William Herschel, to undertake his vast labor on the Dou- 

 ble Stars, it is not strange that the younger Herschel should have been 



