72 Mr. H. H. Ho worth on 



specific gravity when it is hot than when it is cold ; and as the 

 statical equilibrium of liquids is dependent on there being 

 equal pressures on equal areas, the surface, instead of being a 

 flat plane, will form a slope from the lightest, and therefore 

 highest part of the water to the densest or lowest. Thus, if the 

 water is warmer at the equator than at the pole, the water 

 must stand higher in the former district than the latter, 

 and there must be a slope from one to the other. 



Such a slope, while securing statical equilibrium to the 

 mass must cause a molecular disturbance, since the particles 

 of water on it will begin to roll down, until a perfect level is 

 secured ; and it is clear, as Dr. Croll urges, that we can never 

 secure both conditions of equilibrium at the same time so long 

 as a difference in temperature exists between the two areas 

 {Climate and Time,op. cit., 178) ; but this molecular movement 

 of the surface particles of the water to restore a dead level 

 continually could not clearly create a circulation of the ocean. 

 Nor could a circulation of the water be produced so long as 

 the whole mass was in statical equilibrium, and when there 

 would consequently be no tendency to circulate at all. This 

 equilibrium must be disturbed in some way, and this can 

 only be by the denser column of water, namely, that at the 

 poles being kept at a higher or a lower level than it would 

 be if in equilibrium. Such a column would then do more 

 or do less than balance a similar column of the water at the 

 equator and statical equilibrium would thus be disturbed. 



But this involves an appeal to some other factor than a 

 difference of specific gravity which could not permanently 

 keep up an inequality of balance between a column of 

 water at the pole and one at the equator. Maury, however, 

 makes no such appeal. His argument is therefore suicidal. 

 Dr. Carpenter, unlike Maury, does not postulate a slope 

 between the equator and the poles down which the water 

 flows. He denies its existence and its necessity. 



According to him, the cold in the Arctic regions con- 



