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learned by extending the inquiry to other gaseous bodies. The re¬ 
sults are shown in the following tables. 
Ammonia NH 3 ; carbon disulphide CS 2 . From the follo¬ 
wing data 
nh 3 cs 2 
a) À = 5,893 ... v= 1,0003730 ... v = 1,00148 
b) 6,708 . . . 3712 ... 146 
due to L. Lorenz, we obtain 
NH 3 . . . A — 2,97 
CS 2 . . . A = 2,22 
Sulphurous oxide S0 2 . In Dufet’s work quoted above (p. 78) 
Ketteler is said to have found for S0 2 : 
a) X = 5,350 ... v = 1,000691 
b) 5.893 ... 686 
c) 6.708 . . . 682 
From (a) and (c) ... A = 2,25 
... ( b ) and (c) . . . 1,95 
Nitrous oxide N 2 0. According to Mascart (Dufet, l. c., p. 77) 
we have for this gas 
a) 1 = 4,800 ... v = 1,0005230 
b) 5,085 . . . 5207 
c) 5,378 . . . 5192 
d) 5,896 . . . 5152 
e) 6.438 ... 5132 
The figure given under wave-length (c) appears to be erroneous. 
We obtain 
from (a) and (e) ... A = 2,84 
... (a) and (d) ... 2,97 
... (b) and (d) ... 3,10 
. . . (b) and (e) ... 2,89 
Cyanogen C 2 N 2 . From Ketteler’s data (Dufet, l. c., p. 74) 
a) l = 5,350 ... v = 1,000789 
b) 5,893 ... 784 
c) 6,708 ... 780 
