J. W. Gibbs—Electromagnetic Theory of Light. 107 
Arr. X.— Notes on the Electromagnetic Theory of Light; by 
J. WinLARD Gipss. No. III. On the General Equations of 
Monochromatic Light in Media of every degree of Transparency. 
h waves of light, in 
which they are regarded as consisting of solenoidal electrical 
physical properties on which transparency depends, and that 
the electrical motions were not complicated by any distinc- 
Influence, except that an oscillating magnetization of 
medium will be excluded.t 
order to conform as much as possible to the ordinary 
of electrical phenomena,§ we shall not introduce at first 
. See volume xxiii of this Journal, pages 262-275, and 460-476. 
t This aper contains, with some additional developments, the substance of a 
Communication to the National Academy of Sciences in November, 1882. ; 
ere a body capable of magnetization is subjected to the influence of light, 
(as when light is reflected from the surface of iron.) there are two simple h 
p ; 
n 
view 
? 
is hor adi dificult respite or disprove, and certainly presents more 
culties of comprehension, than the connection of optical and electrical phenomena, 
and which, as resting largely on @ priori considerations, must naturally appear 
very differen ly to different minds. Moreover, the mathematical method by 
Which the subject was treated, while it will remain a striking monument of its 
author's originality of thought, and profoundly modify the development of mathe-— 
