285 
Round it was a faint envelope, in which were close dark 
bands, not traced in the 
spark itself. With gauge 
0'.85, they extended over 
all, about 50 to the inch, 
black and sharply defined. 
With 0:07 the appear- 
ance was superb, some- 
thing like the sketch. 
*< There are about 25 
of the menisci whose con- 
centricity with the lumi- 
nous point on the ball I ‘rane 
» : “tm 
verified by comparing i 
them with circles drawn 
on paper, and placed be- 
hind the receiver; the 
lowest I estimated at 
125 broad. Below the 
dark space the light dou- 
bled over the disc, but 
without rings, and then 
clothed the stem with its 
purple envelopes. There 
was no fluorescence, at 
least not enough to make 
Tete 
: iiledediliaaiaine 
the quinine drawings vi- mm mn 
sible. This was repeated 
with ball terminals, ex- 
hausting the receiver four 
times successively, as 
often filling it with hydro- 
gen, and leaving it as 
many days in contact with 
the sulphuric acid. The interval of the balls was three inches, 
