572 
GEOPHYSICS: L. A. BAUER 
Proc. N. a. S. 
These differences and contrasts on the one hand perpetually disturb 
the orderly arrangement of air densities and pressures demanded by gravity. 
The latter, on the other hand, as perpetually and continuously sets por- 
tions of the air in motion, in order to establish and maintain a state of 
equilibrium, which, however, is never attained. We must clearly recog- 
nize that the ceaseless complex changes in and motions of our atmosphere 
represent in fact the only state of equilibrium possible between gravity 
on the one hand and solar heating of the earth on the other. 
The disposition on the part of some to attribute important phenomena 
of terrestrial weather to minor solar activities is believed to be a mistake. 
It is in fact believed that apparent changes in solar activity, especially 
of the thermal character, are in reality altogether of terrestrial origin and 
that the imaginary correlations between terrestrial and solar activities 
are really the simple relations between atmospheric phenomena at one point 
and possibly those at another on the earth itself. It is most important 
that these major problems of cause-and-eifect relation between solar 
and terrestrial activities should be observed, not only with the greatest 
possible accuracy but that the observational data themselves should be 
thoroughly analyzed and discussed, first, to establish the magnitude of 
the errors of the observation, and second, to determine the possible re- 
lations between solar and atmospheric effects. 
Seemingly the greatest need in meteorology is that of a master mind 
to direct itself comprehendingly and intensively to the great problems 
which the science still presents. 
SOME OF THE CHIEF PROBLEMS IN TERRESTRIAL 
MAGNETISM AND ELECTRICITY 
By Louis A. Bauer 
1. Analysis oj the Earth's General Magnetic Field: The early comple- 
tion of the general magnetic survey of the globe, as undertaken by the De- 
partment of Terrestrial Magnetism of the Carnegie Institution of Wash- 
ington and cooperating countries, will afford the necessary data for the 
investigation of some of the so-called "greater problems of the earth's 
magnetism." One of these is the determination of the various systems 
of magnetic and electric forces which together make up the total terres- 
trial magnetic field as observed at the earth's surface. It is known from 
previous analyses that the earth's magnetic field consists of an internal 
system of forces, which constitutes by far the major portion; secondly, 
an external system, supposedly to be ascribed to electric currents circula- 
ting in the earth's atmosphere; and, thirdly, a system possibly such as 
that of vertical electric currents which pass from the atmosphere into the 
earth and vice versa. The definite settlement of the question as to the 
existence of the third system is regarded by Sir Arthur Schuster as one 
