68 New Theories of the Great Forces. 



within the boundaries of a wind produced by 

 the action of more general, and widespread 

 causes A wind within a wind. 



The above instances plainly carry a sug- 

 gestion of magnetic origin and power. 



Winds may notarise from Presumed Causes. 



If winds are due to such a simple mechani- 

 cal causation as the production by the sun, 

 of a rarefied atmosphere, the colder air 

 rushing in from all sides into the empty 

 spaces, we should hardly expect to find any 

 definite currents bounded by well-defined 

 limits ; much less should we look for trans- 

 verse and opposite currents going like mes- 

 sengers at varying rates of speed, some slow, 

 and others exceedingly swift. Nor may 

 stronger gales suddenly cease, as though 

 stopped by some mighty invisible wall. And 

 in no wise can they, from mere calorific agen- 

 cies, leap out of perfect calmness into hurri- 

 cane velocity, or subside into silence as by 

 magic. On no such principle can they shift 

 back upon their own track, going either way 

 with terrific velocity. 



