1. Draper—Discovery of Oxygen in the Sun. 95 
tion coil when it first reached me, because when the whole 
generally, in order to get the maximum effect, I arrange the 
current so that the aluminium terminals are on the point of 
melting. The glass, particularly in the capillary part, often 
gets so hot as to char paper. The general appearance of the 
machine is shown in fig. 1. 
The Gramme Machine. 
As long as the Gramme bobbin is driven ata steady rate 
the current seems to be perfectly constant, but variations 0% 
Speed make marked differences in the current, and this is espe- 
cially to be avoided when one is so near the limit of endurance 
of Pliicker's tubes. A reliable and constant motor is therefore 
