CuAP. XVII.] THE WINDS AND EVAPOEATION. 185 



This last remark refers to the fact of the water 

 in the west of the equatorial regions, in each ocean, 

 being warmer than in the east ; so that, if the expan- 

 sion of the water by heat caused an overflow, the 

 stream caused by that overflow would run from west 

 to east ; whereas the general course of the water m 

 the equatorial regions is from east to west. It may 

 here also be remarked, in connection with one of the 

 quotations above, that, the heating action of the 

 sun's rays is, by Sir John Herschel himself, admitted 

 to tend to cause the surface-water of the ocean to 

 ascend (causing it to leave the sea in the form of 

 vapour) ; and, thus, to tend to cause an indraught 

 towards the places of maximum evaporation.^ The 

 effects resulting from this action are, in fact, discussed 

 in the preceding quotation made from Sir John 

 Herschel.^ 



' The places of maximum evaporation being tlie equatorial 

 regions, the surface indraught would be to those regions ; and the 

 ' additional density acquired by evaporation/ as stated in the first 

 of the above extracts from Herschel, would obviously, as indicated 

 in the text above, have a tendency to neutraUse the buoyancy 

 suggested in the second extract, and therefore to cause the water 

 to sink in those regions. This action has been elaborately dis- 

 cussed by Mr. CroU. Climate and Time : by James CroU, London, 

 1875. 



2 The conflicting action of the ' additional density acquired by 

 evaporation ' and the ' buoyancy acquu'ed by being heated ' are 

 indicated in the text above, which stands as first published in 

 Chapter lY. of the Treatise on Vis-Inert ice, and makes it evident 

 that I did not desire to endorse the details of the arguments used 

 by Sir John Herschel. 



