MAGNETISM AND CIRCULATION OF THE ATMOSPHERE. I47 



394. Thus, though it be not proved as a mathematical truth 

 that magnetism is the power which guides the storm from right 

 to left and from left to right, which conducts the moist and the 

 dry air each in its appointed paths, and which regulates the "wind 

 in his circuits," yet that it is such a power is rendered very prob- 

 able ; for, under the supposition that there is such a crossing of 

 the air at the five calm places, as Plate, p. 75, represents, we can 

 reconcile a greater number of known facts and phenomena than 

 we can under the supposition that there is no such crossing. The 

 rules of scientific investigation always require us, when we enter 

 the domains of conjecture, to adopt that hypothesis by which the 

 greatest number of known facts and phenomena maybe reconciled; 

 and therefore we are entitled to assume that this crossing proba- 

 bly does take place, and to hold fast to the theory so maintaining 

 until it is shown not to be sound. 



395. That the magnetism of the atmosphere is the agent which 

 guides the air across the calm belts, and prevents that which en- 

 ters them from escaping on the side upon which it entered, we 

 can not, of our own knowledge, positively affirm. Suffice it to 

 say, that we recognize in this property of the oxygen of air an 

 agent that, for aught we as yet know to the contraiy, may serve 

 as such a guide ; and we do not know of the existence of any oth- 

 er agent in the atmosphere that can perform the offices which the 

 hypothesis requires. Hence the suspicion that magnetism and 

 electricity are among the forces concerned in the circulation of the 

 atmosphere. 



