W. A. Norton on Molecular Physics. 75 
succeeding period. Since it appears from Mr. Schott’s discus- 
sion of the secular variations (see Report of Coast Survey for 
1855, p. 337), that the secular period is shortening on the west- 
ern coast of the Atlantic, we have to infer that we are at present 
in that magnetic phase in which the reinforcement of intensity, 
from the new currents, is less than the annual diminution. In 
this circumstance we have the probable explanation of the an- 
nual diminution of the horizontal force in the United States and 
anada, An increase of the photospheric currents may codperate. 
b 
zontal force. This supposed action of the solar matter upon the 
crust of the earth may arise either from the direct propagation 
of the impulses, as already intimated; or more probably from 
0 Increase in the density of the ether, resulting from the accel- 
fration of the fall of the matter in question, produced by the 
th’s attraction. 
there is abundant evidence of such dependence, The annual 
Fates of variation of all the magnetic elements, vary during the 
