BALLOONS 
247 
and hope it will not make us slack ; but it is good to 
see everyone in such excellent spirits — so far not a rift 
in the social arrangements. 
Monday, April 24. — A night watchman has been 
instituted mainly for the purpose of observing the aurora, 
of which the displays have been feeble so far. The 
observer is to look round every hour or oftener if there 
is aught to be seen. He is allowed cocoa and sardines 
with bread and butter — the cocoa can be made over an 
acetylene Bunscn burner, part of Simpson's outfit. I took 
the first turn last night ; the remainder of the afterguard 
follow in rotation. The long night hours give time to 
finish up a number of small tasks — the hut remains quite 
warm though the fires are out. 
Simpson has been practising with balloons during 
our absence. This morning he sent one up for trial. 
The balloon is of silk and has a capacity of 1 cubic metre. 
It is filled with hydrogen gas, which is made in a special 
generator. The generation is a simple process. A vessel 
filled with water has an inverted vessel within it ; a pipe 
is led to the balloon from the latter and a tube of india- 
rubber is attached which contains calcium hydrate. By 
tipping the tube the amount of calcium hydrate required 
can be poured into the generator. As the gas is made 
it passes into the balloon or is collected in the inner vessel, 
which acts as a bell jar if the stopcock to the balloon is 
closed. 
The arrangements for utilising the balloon are very 
pretty. 
An instrument weighing only z\ oz. and recording the 
