333 
The dispersion of hydrogen, however, has been investigated by 
several observers. L. Lorenz x ) gives 
a) X = 5,893 ... y = 1,0001387 
b) 6,708 ... 1380 
From these it follows 
D = 10629 A = 8,35. (2) 
F. Perreau’s results 2 ) for hydrogen are given below: 
a) À = 
: 4,677 . . . 
v = 1,0001408 
b) 
4,800 . . . 
1406 
c ) 
5,085 . . . 
1400 
d) 
5,378 . . . 
1393 
e) 
5,896 . . . 
1390 
f) 
00 
CO 
cd' 
1385 
We obtain: from 
a) and f) . 
. . A = 8,37 
b) and e) 
8,31 
. . . 
c) and d) . 
8,58 
If we assume A = 8,35 Mr. Perreau’s data give for I) 
a) 11035 b) 11032 c) 11034 
d) 11035 e) 11031 f) 11035 
The formula is thus seen to agree with observation. If now we 
put 11033,5 for D, Mr. Perreau’ s data give for A 
a) 8,33 b) 8,38 c) 8,34 
d) 8,30 e) 8,41 /) 8,29 
We shall not prolong this process of successive approximations; 
we take 
D = 11033,5 and A = 8,343 (3) 
as values of the constants agreeing well with Mr. Perreau’s expe¬ 
rimental results. 
*) Annalen d. Phys. u. Chemie, Bd. 11 ., p. 98. 1880. 
2 ) Journal de Physique (3) Yol. 4., p. 415. 1895. 
Bulletin III. 
6 
