Chemistry and Physics. 59 



the size of the Gulf-stream would be sufficient to keej) the cntii-e 

 water of the globe (below the stratum heated by the sun's rays) 

 at an ice-cold temperature. Internal heat would not be sufficient 

 under such circumstances to maintain the mass 1^ Fahr. above 

 the temperature it possessed when it left the polar regions. 



In short, whatever theory we adopt regarding oceanic circula- 

 tion, it follows equally as a necessary consequence that the entire 

 mass of the ocean below the stratum heated by the sun's rays 

 must consist of cold water. For if cold water be continually com- 

 ing from the polar regions, either in the form of under-cnrrents, 

 or in the form of a general underflow as Dr. Carpenter supposes, 

 the entire under portion of the ocean must ultimately become 

 occupied by cold water ; for there is no source from which this 

 influx of water can derive heat, save from the earth's crust, which 

 amount is so trifling as to produce no sensible effect. 



It is therefore evident that the great mass of cold water occu- 

 pying the depths of the ocean cannot be urged as an objection to 

 the wind theory. 



2. But it is asserted that the impulse of the wind on the surface 

 of the ocean cannot produce and maintain deep under-currents. 

 This is an objection which has been urged by some eminent phys- 

 icists ; but it is based upon a misapprehension of the manner in 

 which, according to the wind theory, under-currents are produced. 



It is true, as the objectors maintain, that a wind simply impel- 

 ling the water forward will not necessarily produce an un<ler-cur- 

 rent, since compensation will more readily take place by return 

 surface-currents, as in this case the path of least re^istatK'e will 

 generally be at the surface. But when the general surface of one 

 half of an ocean basin is being constantly impelled forward by 

 prevailing winds in a contrary direction to that in which it is 

 being impelled in the other half, compensation cannot possibly 

 take place by means of return surl'ace-currents. For a full discus- 

 sion of this point I must refer the reader to my work, " Climate 

 and Time," Chap. XIII. 



It is, however, needless to advance arguments d priori against 

 the possibiliy of such under-currents; for we have actually several 

 well-known examples of such currents, the particulars of which 

 will also be found in the work to which I refer. 



3. But supposing it could be shown that the winds cannot 

 directly produce under-currents, it can nevertheless be demon- 

 strated that they can do so indirectly. A vertical circulation fdl- 

 iijg the deep recesses of the ocean under the equator with j)olar- 

 cold water, follows as readily and truly from the wind theory as 

 it does from the gravitation theory. It has been shown that" the 



- ■■ ral tendency of the system of the winds is to impel tlie sur- 

 \r:iter of the equatorial regions into the temperate and p<^)lar 

 :is as rapidly as it is heated. But such a transference of 

 . tend to destroy static equilibrium by making 



