204 TROWBRIDGE. — HIGH ELECTROMOTIVE FORCE 
i faint shadow of lightning, — so faint that it fails to reproduce in most essentia 
ipects the phenomena in the heavens. I have never been able, by the use of reso 
nt tubes or other arrangements, to cause reverberations to reproduce in the slight 
, o 
est degree, even with sparks six feet in length, the rolling of thunder. The energy 
of an ordinary lightning discharge must be enormous. 
The forms of lightning discharges are very varied, and when one asks whether 
lightning is oscillatory, one should specify the kind of discharge. 
SPECTRUM ANALYSIS WITH CURRENTS OF HIGH ELECT ROMOTIVE FORCE 
AND STRONG CURRENTS. 
For several years I have been endeavoring to obtain new series of hydrogen lines 
which might presumably manifest themselves at very high temperatures. In the 
progress of this work I have obtained a number of interesting facts, but I have foiled 
to find a new series of hydrogen lines; possibly the reactions both in glass and quartz 
jssels mask the series. It seems impossible to experiment at a higher temperature 
than I have obtained, certainly if one employs such vessels as I have mentioned. 
The advantages in using a storage battery for experiments in spectrum analysis 
v 
recognized. These ad 
° o 
especially seen in the employment of 
denser discharges. When the condensers are charged through a large liq 
they charge to the same potential each time, and then <lisch„. s ~, 
the intervention of a discharger, through the Geissler tube. The number of d 
charges can be closely regulated by th 
of liquid 
trement 
the poles of the condensers to the battery. The regularity of such discharges through 
the Geissler tubes is remarkable. In popular language one can call the arrar 
an electric clock, for the discharges follow each other at regular intervals. In this 
way one avoids the spark at a discharger and is sure of always obtaining the same 
difference of potential at the ends of the Geissler tub* 
The big 
n 
lest temperature to which one can submit a gas is presumably that of 
elect™ d.scharge from a condenser; opinions differ in regard to (be decree of h 
winch one can obtain by such a discharge. The limit I have reached is • 
tion ot silica, - perhaps 1800 degrees. At this temperature the spectrum shown by 
all gases m narrow capillary tubes consists of a continuous spectrum crossed by broad 
bands due to s.bca or to an oxide of silica ; the gaseous spectra arc completely masked, 
this masking seems to be dne to the greater conductibility of the volatilization 
products from the walls of the tubes and from the metallic terminals, ft seems to me 
