THE DEVELOPMENT OF METEOROLOGY. 
45 
sphere as two disturbing forces of equal magnitude, acting 
on the air above these in such a way as to cause these halves 
of the earth’s atmosphere to react on each other in a series 
of movements or perturbations most delightful to contem- 
plate and most inspiring to the mathematical expert, who 
quickly acquires a grim determination to solve the problems 
that are presented. This interaction of the continental and 
oceanic hemispheres is responsible for the fact that what 
happens in India in its summer by reason of the special char- 
acter of its monsoon is not only related to what happens in 
Africa and Siam, but even to what happens in Australia and 
America. A most interesting evidence of the recognition of 
this principle will be found in the fact that Mr. Gilbert T. 
Walker, the meteorologist of the Indian Service, in his an- 
nual forecast of the Indian monsoons makes a statement of 
the conditions affecting the monsoon rainfall in which he 
includes the precedent conditions over Australia, South 
America, and Siberia; he shows that the Asiatic and equa- 
torial regions, taken by themselves, do not suffice to deter- 
mine the future character of the monsoon. 
A corresponding indication of the broadening of our field 
of view is found in the fact that our own Weather Bureau 
has lately begun to receive telegrams as to the barometric 
pressure prevailing in the interior of Asia, more especially in 
Siberia, under the conviction that the oscillations that take 
place in that region give some indication of what will subse- 
quently occur in our own territory. This idea developed at 
once from our experience during the first year of our forecast 
work in 1871, and led promptly to the establishment of our 
“Bulletin of International Simultaneous Meteorological Ob- 
servations” with its daily charts of the northern hemisphere, 
undertaken bv General A. J. Myer in 1873, in accordance 
with the idea that the atmosphere must be studied as a unit. 
His published bulletin of international observations gives us 
a daily map of the whole northern hemisphere from 1875 to 
1884, after which only monthly maps were published. But 
the daily manuscripts have continued to be compiled up to 
the present time, although on a somewhat different plan. 
