2 2 HEAT A MODE OF MOTION. 



stream-currents is due to the influence of solar heat, 

 is one which is now very generally accepted. 



So long ago as 1833 the astronomer Herschel laid 

 it down as a fundamental axiom "that the sun's rays 

 are the ultimate cause of almost every motion that 

 takes place on the surface of the earth, " * and in 

 eloquent terms he proceeded to point out that by heat, 

 as its motive principle, the whole material world lives, 

 and moves, and has its being; and the investigations 

 of scientific observers have since gone far to establish 

 the correctness of Sir John Herschel's conclusions; the 

 passage here referred to has moreover been quoted 

 and relied upon as that of a leading scientific autho- 

 rity by Professor Tyndall, in his well-known treatise 

 on "Heat." f 



The Encyclopedia Britannica in the section devoted 

 to the Ocean Currents of the Atlantic, also states, 



" The solution of the problem seems to be afforded by 

 'A General Oceanic Circulation' sustained by opposition of 

 temperature only, which was first distinctly propounded in 

 1845 by Professor Lenz of St. Petersburg. He particularly 

 dwelt on the existence of a belt of water under the equator, 

 colder than that which lies either north or south of it, as 

 evidence that polar water is there continually rising from 

 beneath towards the surface a phenomenon which he con- 

 sidered admits of no other explanation." 



And it also appears that unaware of these opinions 

 expressed by Professor Lenz in 1845, "Dr. Carpenter 

 commenced in 1861, in concert with Professor Wyville 

 Thomson, a course of enquiry into the thermal condi- 

 tion of the deep sea, which led him to conclusions es- 



* Outlines of Astronomy, by Sir John Herschel, 1833. 



t Heat a Mode of Motion, by John Tyndall, F.R.S., 5th edit., p. 478. 



$ EncvcL Brit., qth edit., Vol. iii., p. 22 (Art. "Atlantic Ocean"). 



