FAILURE OF CLIMATIC THEORIES. 15 



is not far distant when the climate controversy will 

 be concluded. When the fact comes to be generally 

 admitted by physicists that a great increase in the 

 temperature and volume of the ocean currents flowing 

 polewards is sufficient to prevent the accumulation of 

 ice in the Arctic regions, it will then be allowed that 

 we only require a great decrease in the volume and 

 temperature of the currents in order to account for the 

 former accumulations of ice on the temperate regions, 

 or, in other words, to explain the occurrence of the 

 Glacial Epoch. And when this position is reached, it 

 will be seen that the whole depends upon a very 

 simple cause, requiring neither the submergence nor 

 the elevation of continents, nor any other great change 

 in the physical geography of. the globe. 



When the eccentricity of the earth's orbit is at a 

 high value, and the Northern winter solstice is in 

 perihelion, agencies are brought into operation which 

 make the S.E. trade winds stronger than the N.E., 

 and compel them to blow over upon the Northern 

 hemisphere as far probably as the Tropic of Cancer. 

 The result is that all the great equatorial currents of 

 the ocean are impelled into the Northern hemisphere, 

 which thus, in consequence of the immense accumu- 

 lation of warm water, has its temperature raised, and 

 snow and ice to a great extent must then disappear 

 from the Arctic regions. When the precession of the 

 equinoxes brings round the winter solstice to aphelion, 

 the condition of things On the two hemispheres is 

 reversed, and the N.E. trades then blow over upon 

 the Southern hemisphere, carrying the great equatorial 

 currents along with them. The warm water beino- 

 thus wholly withdrawn from the Northern hemisphere, 

 its temperature sinks enormously, and snow and ice 

 begin to accumulate in temperate regions. The amount 



