436 PHILOSOPHY OF STORMS. 



the mean all round the tornado or water spont, in an annu- 

 lus, in consequence of the rapid efflux of the air above in 

 all directions from the centre of the cloud, the air at some 

 short distance beyond the annulus will move gently out- 

 wards, at the surface of the earth from the tornado. This 

 outward motion will have a tendency to form anew upmov- 

 ing column on the windward side of the tornado, by its 

 causing a resistance to the regular current of the air, and 

 even on the leeward, it has the same tendency, by protrud- 

 ing the air faster in that direction than the common cur- 

 rent of air is moving on that day. This will appear to any 

 one who shall think on the subject carefully without any 

 further elucidation from me. On the other hand, the more 

 anyone thinks of tops spinning round in the air, as the Pro- 

 fessor said he conceived these spouts do, the less analogy 

 will he see between them and this forest of. water spouts, 

 as the Professor called them, for the tops would immediate- 

 ly fly all to pieces, and cease whirling, if the cohesion of 

 their particles should be destroyed, and so it would be with 

 the air, even if it should bo put into a whirling motion by 

 some unknown cause, as its particles have no cohesion. 



If, indeed, it should commence whirling without a cause 

 and no cause has ever been adduced for it it might, for 

 aught 1 know, continue to whirl without a cause. 



My theory does not necessarily imply, that there are " par- 

 ticular patches " either on land or sea, warmer than else- 

 where, which are necessary to the origin of upmoving col- 

 umns on the contrary, if the air at the surface of the 

 earth or sea for thousands of miles around, should become 

 heated, more than the air just above, or should become more 

 highly charged with vapor, it would in either case form an 

 unstable equilibrium, and it would be as philosophical to 

 suppose that a needle nicely balanced on its point, would 

 remain so forever in an agitated atmosphere, without falling, 

 as to suppose upmoving columns of air would riot be formed 



