EQUIPMENTS ON BO ABB. 
9 
from the rolling of the ship by many ingenious 
devices. 
The photographic quarters faced the laboratory, 
and consisted of a dark room and studio, where were 
ranged the bottles, chemicals, and apparatus required 
by the operator. 
CHEMICAL LABORATORY ON BOARD THE CHALLENGER. 
A large aquarium was near at hand ; while the 
water bottles and sounding-machines were secured 
close by in racks against the ship’s side. 
On large reels were coils of telegraph insulated 
wire, for the purpose of obtaining the temperature 
at different depths by galvanic influence. 
