Chase. | 68 [April 7, 
RESEMBLANCE oF Atmospheric, Magnetic and Oceanic Currents. 
By Pursy EARLE CHASE. 
(Read before the American Philosophical Society, April 7, 1871.) 
My belief that terrestial magnetism is dependent solely upon fluid cur- 
rents, electrified by convection and by the condensation of vapor, led me 
to look for some confirmation of my views in the results of my recent 
discussions of the winds of the United States. My attention was first 
drawn to the resemblance between the looped isogonic lines in the eastern 
equatorial portion of the Pacific Ocean, and the anti-cyclonic course of the 
winds in the Gulf States. The undoubted rapidity of macnetic action, 
a rapidity analogous to, if not identical with, that of luminiferous vibra- 
tions, renders it probable that the flexure of the isogonic lines, at any 
given point, may be determined by the resultant of all the forces acting 
at that point, and that the equatorial loops are, therefore, expressions of 
equatorial disturbance. 
Tf the same disturbance is communicated to the more sl uggish air, its 
culmination may naturally be sought at some point northward and east- 
ward, because of the well-known laws of current deflection. The prin- 
cipal thermal contrasts which contribute to the establishment of currents, 
are: 1st, land and water; 2d, polar and equatorial; 3d, heat and cold at 
isabnormal centres. It seems reasonable te suppose that these triple con- 
trasts should be so mutually related, that there may be some system of 
rectangular codrdinate planes which would present each of them as a 
maximum. 
A great circle cutting the equator on the meridians of 100° W. and 80° 
£., and passing through the geographic centre of the land hemisphere, 
follows the general trend of the American coast from Florida to New- 
foundland, skirts the equatorial isogonic and the Florida atmospheric 
loops, finds the western limit of our anti-cyclonic system of winds 
at a point about midway between the magnetic pole and the equator, 
and crosses the equator on the meridians and near the centres of greatest 
Horizontal Force. A co-ordinate great circle following the meridians of 
10° W. and 170° E., intersects the magnetic equator of minimum inten- 
sity near its greatest northern and southern elongations. The third 
co-ordinate great circle corresponds very nearly with the dividing plane 
between the land and water hemispheres. The principal north pole of 
declination and the Asiatic equatorial intersection of the line of no varia- 
tion, are on the meridians first named, which traverse the intersections 
of the first and third co-ordinate circles. A great circle intersecting the 
second co-ordinate on the equator, and passing near the North American 
pole of declination, would cut the first of these meridians (100° W.) at 
an angular distance from the pole analogous to that of the Florida wind 
loop from the equator, traversing the principal isogonic loops in such 
manner as to exhibit the magnetic symmetry of the entire globe to the 
best advantage. No other system of rectangular co-ordinate planes 
would meet with so little Jand interruption, or would divide the globe 
jnto hemispheres with so great current-producing contrasts. 
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