THE GULF STREAM AND DEEP SEA CURRENTS. 171 



and by each attracting its lik<-, tliry ncutrali/.i- each other; 

 this process, as wo have said, is continually proceeding all over 

 the surface, and throughout the whole body of the oceans. 



To press the question still further, the atmosphere is also 

 being charged continually with all sorts of gaseous impurities 

 induced by the heat of the sun, and given out by plants and 

 animals. Does Dr. Carpenter mean to affirm that we must wait 

 for a storm to blow them away, or must they also travel to the 

 Poles to be purified. In either case a plague would probably 

 result before we could be relieved by these modes. The phe- 

 nomenon of dew shows us that the reciprocal circulation is 

 continually in progress, and that even when there are no winds 

 blowing, the purification of the atmosphere is accomplished 

 by the chemical action of the atoms. 



This leads us to ask the question why Dr. Carpenter has not 

 endeavoured to found a general system of atmospheric circulation, 

 on the same principle as that of the oceanic. If the law is 

 good in the one instance, it ought to hold good in the other. 

 He would then have made his theory complete, for the cold 

 Polar current of air being mineral, would be the highest, and 

 this would form an upper current from the Poles towards the 

 Equator, while the warm vegetable atmosphere being denser, 

 would travel on the surface from the Equator along with the 

 warm current of water to the Poles, the one thus helping along 

 the other. A beautiful and complete theory of ocean and air cur- 

 rents would thus be enunciated, the motions of the one accurately 

 fitting into the motions of the other. But unfortunately, he 

 only managed to grasp the least acceptable theory, for as we have 

 shewn in the chapter on Atmosphere, there is more than a grain 

 of truth in the theory of the upper atmospheric current, while 

 there is none in that of the oceanic. 



