250 Mr. P. E. Chase on the Cosmical Activity of Light. 



Ocean, as ascertained by the 'Challenger' expedition, appears 

 to me to be also irreconcilable with the gravitation theory. Be- 

 tween the parallels of latitude 65° 42' S. and 50° 1' S., the 

 ocean, with the exception of a thin stratum at the surface heated 

 by the sun's rays, was found, down to the depth of about 200 

 fathoms, to be several degrees colder than the water underneath *. 

 The cold upper stratum is evidently an antarctic current, and the 

 warm underlying water an equatorial under-current. But, ac- 

 cording to the gravitation theory, the colder water should be 

 underneath. 



The very fact of a mass of water 200 fathoms deep, and ex- 

 tending over 15 degrees of latitude, remaining above water of 

 three or four degrees higher temperature shows how little influ- 

 ence difference of temperature has in producing motion. If it 

 had the potency which some attribute to it, one would suppose 

 that this cold stratum would sink down and displace the warm 

 water underneath. If difference of density is sufficient to move 

 the water horizontally, surely it must be more than sufficient to 

 cause it to sink vertically. 



It is difficult at present to estimate properly the importance 

 of these results ; for as oceanic circulation is the great agent in 

 the distribution of heat over the globe, if it can be proved that 

 this circulation is produced not by gravitation but by the system 

 of prevailing winds, it is also proved that the thermal condition 

 of the globe is dependent upon the prevailing winds, and that, 

 consequently, any cause which will greatly affect the system of 

 the winds will greatly affect the climatic condition of the globe. 

 This necessary connexion between the system of the winds and 

 the climatic condition of the globe leads us step by step towards 

 the solution of the great problem of geological climate. 



XXVII. Cosmical Activity of Light. By Pliny Earle Chase, 



Professor of Mathematics in Haverford College^. 



IN cosmical movements there are three prominent velocities, 

 which may vary so as either to approach towards or to recede 

 from equality : — 



1. The velocity due to circular revolution at a given point, 



varying as \ /-• v r 



2. The velocity of rotation for the same radius, or revolution 



retarded by internal work, varying as -. w 2 . 



* Captain Nares's Report, July 30, 1874. 

 t Communicated by the Author. 



