160 LIGHT SCIENCE FOR LEISURE HOURS. 



thus speaks of its destructive effects. ( I saw, to my 

 great astonishment, that the noblest trees of the forest 

 were falling into pieces. A mass of branches, twigs, 

 foliage, and dust moved through the air, whirled 

 onwards like a cloud of feathers, and passing, disclosed 

 a wide space filled with broken trees, naked stumps, 

 and heaps of shapeless ruins, which marked the path 

 of the tempest.' 



If it appeared, on a careful comparison of observa- 

 tions made in different places, that these winds swept 

 directly along those tracks which they appear to follow, 

 a comparatively simple problem would be presented to 

 the meteorologist. But this is not found to be the 

 case. At one part of a hurricane's course the storm 

 appears to be travelling with fearful fury along the 

 true storm- c^ ; at another less furiously directly 

 across the storm-track ; at another, but with yet 

 diminished force, though still fiercely, in a direction 

 exactly opposite to that of the storni'-track. 



All these motions appear to be fairly accounted for 

 by the theory that the true path of the storm is a 

 spiral or rather, that while the centre of disturbance 

 continually travels onwards in a widely extended 

 curve, the storm-wind sweeps continually around the 

 centre of disturbance, as a whirlpool around its 

 vortex. 



And here a remarkable circumstance attracts our 

 notice, the consideration of which points to the mode 

 in which cyclones may be conceived to be generated. 

 It is found, by a careful study of different observations 



