336 
LITTLEHALES. 
registration-observatories that have been established in va¬ 
rious countries. Investigators although not assuming be¬ 
forehand the existence of a magnetic potential, have never¬ 
theless found evidence that the effects of the diurnal changes 
are deducible from such a potential, and in giving proofs 
that their primary cause comes to us from outside the 
Earth’s surface, have marked out the avenue of approach 
toward a solution of the internal electrical, conductivity 
of the Earth, the external conductivity of space, and the 
great problem of solar influence in terrestrial phenomena. 
In a memorable series of investigations on the decompo¬ 
sition of the Earth’s permanent magnetic field, in which 
the principal features of the distribution of magnetic forces 
on the surface of the Earth are considered to be roughly 
represented by harmonics of the first degree and are thus 
calculated and subtracted from the actual forces in order to 
discover where the centers lie which render the surface dis¬ 
tribution unsymmetrical, Bauer of Washington, building 
on the broad foundation laid by Gauss and utilizing the 
splendid recomputations of the Gaussian coefficients that 
have been made by Schmidt in Germany and Adams in 
England, has established the widely ramifying relations be¬ 
tween terrestrial magnetism and the other earth-sciences, 
has found the secular change in the Earth’s magnetism io 
be due to two systems of magnetic or electric forces, situated 
partly within and partly without the solid substance of 
the Earth, which in the course of time cause changes both 
in the direction and intensity of magnetization, and has 
forged the key with which to unlock portals leading to a 
knowledge of the inner state and history of our planet. 
Professor Fleming has aptly said that “ Our investiga¬ 
tions lead to the conclusion that the Earth is alive with 
ever changing magnetic forces, and that its magnetic state 
at any point is not only altering in a slow progressive man¬ 
ner, like the solemn march of the constellations in the 
heavens, but has its daily tides like the ocean, and also like 
the restless sea, is ever and again thrilled with little ripples 
