CH. LVI] 
The Societies" Expedition 
45i 
views, and the idea was strongly supported by Sir Joseph 
Hooker. Accordingly the necessary gear was provided, and 
an officer and two men went to Aldershot for instruction. 
The balloon was of the army pattern, and the gas was 
taken in sixty heavy tubes which were stowed on deck. 
There were also dynamos, for electric lighting. When the 
steam-driven dynamos were not at work, an iron-sailed 
windmill could be fitted, driving the dynamo at its base 
and thus supplying the accumulators with electric current. 
Most of the instruments were lent by the Admiralty — 
astronomical, magnetic, meteorological, pendulum, and 
seismograph, as well as sounding gear with all the newest 
inventions, and dredging nets. 
Baron Richthofen suggested to me that there should 
be synchronous observations at as many other observa- 
tories as possible. Captain Creak fully concurred and, in 
concert with him, I wrote to the observatories at Kew, 
Falmouth, Potsdam, Bombay, Mauritius, Melbourne, and 
Christ Church (N.Z.), also making arrangements with the 
Argentine Government for Staten Island, and for observa- 
tions at Kerguelen Island, and with the Gauss. The 
object was to obtain a series of synoptic charts which 
would allow of the variations in the magnetic conditions 
of the whole earth being traced in detail during a definite 
period, and so provide the necessary basis from which 
alone the fundamental principles of terrestrial magnetism 
can be more closely approached. The observing stations to 
take part in this international co-operation were distributed 
over the globe with a uniformity never before attained. 
The observations were of two classes (1) of the three 
elements at intervals of an hour on certain terminal days, 
so as to obtain a comprehensive view of the diurnal 
variations of terrestrial magnetism, (2) of the three 
elements during one specified hour on each term day, to 
trace the course of individual disturbances. The Dis- 
covery, the Gauss, and all the observatories were supplied 
with identical forms for term days and term hours; 
declination, horizontal force, vertical force. The mag- 
netic observations were the most carefully planned and 
completely thought out of all the branches of scientific 
work carried on by the expedition. 
There was a complete supply of meteorological instru- 
