212 
TROWBRIDGE. 
HIGH ELECTROMOTIVE FORCE 
I have dwelt upon 
broadening of the lines of metals in capillary tub 
Tl 
is 
phenomenon is also observed with hydrogen lines, and was first noticed by Liveing and 
Dewar, Chem. News, XLVII, p. 122, 1883. These authors attributed the broadening 
to compression of the gas in the narrow capillary under the effect of a powerful 
condenser discharge. Their method of experiment was as follows: The tube was 
exhausted only to perhaps five or six centimeters pressure, so that a white discharge 
of a spark nature passed through the capillary and then spread out to electrodes 
placed in the large ends of the tube. When the tube was viewed end-on, a con- 
tinuous spectrum was seen in the capillary ; moreover, this continuous spectrum was 
crossed by a dark line which resulted from the absorption of heat in the colder layers 
of gas in the larger portions of the tube. 
The broadening of the spectra of the vapors of metals which I have observed in 
capillary tubes has thus its analogy in the case of gaseous spectra. 
Having obtained reversals of the spectra of metallic vapors under new conditions, 
I was naturally interested in the experiment of Liveing and Dewar, especially since 
a controversy had arisen between M. Cantor and E. Pringsheim in regard to the possi- 
bility of the reversal of gaseous lines in Geissler tubes, 
his experiments that such reversals do not occur in the pi 
M. Cantor 
i 
ded from 
such 
f him 
one obtains by the discharges of electricity in Geissler tubes 
P-~ e 
objected to these conclusions on the ground that Cantor did not observe a sufficiently 
portion of the spectr 
of th 
gas 
d did not use suffic 
Pringsheim 'quotes the result of Liveing and Dewar in support of his positi 
dispersion. 
repeating Liveing and D 
might be bro 
experim 
d to 
me 
o 
c 
the ground that it was a spark disci 
that obi 
o 
a 
ly marked gl 
lum 
d not 
t dis- 
charge such 
mind 
as Cantor evidently had in 
gap 
I therefo 
F 
placed 
a 
d sp 
Figure E 
gure E) just outside the inner 
pillary of the large Geissler tube 
P 
previously described 
vided 
space 
outsid 
speaking of 
th 
an inner capillary, as I have 
means of an outside 
the capillary passed throu 
The discharge passed 
temperature insid 
a 
first through th 
apillary 
d in the 
through the second spark 
gh the Jijrht from 
gap 
pillary, and then by 
thus the light 
o 
the second 
sp 
g»P 
I 
light from 
both cases 
1 Anil - der Phys.,n.3,1000,p.462. 
Ann. der Phys., n. 5, 1900 
