THE BRUNSWICK LAND SPOUT. 309 



densed vapor, and the increase of the specific gravity of the 

 cloud on that account. 



15. The diminution of specific gravity in the cloud, on 

 account of the higher dew point there than in the surround- 

 ing air. 



16. The increase of the specific gravity of the cloud from 

 the quantity of water it contains, formed out of the con- 

 densed vapor. 



From these data, a general formula for the specific gravity 

 of any cloud formed under given circumstances may be in- 

 vestigated, and the dynamics of the air may thus be brought 

 under the dominion of mathematics. The problem is com- 

 mended to the notice of the profound analysts. 



This lemma will enable the reader to understand the 

 manner in which I conceive the air to rise in tornadoes or 

 water spouts, which I now proceed to investigate. 



The Brunswick Land Spout. 



176. In perusing the phenomena attending this tornado 

 or land spout, let the reader bear in mind the following 

 principles, and he will have no difficulty in understanding 

 not only all the facts detailed, but how the mighty power 

 was generated, and continued so long undiminished, not- 

 withstanding the amazing resistance to the motion of the air 

 at the surface of the earth presented at every moment by 

 the trees and houses overturned. 



The reader will find abundant proof in the subsequent 

 details that the air went up in the middle of the spout with 

 great velocity. Now, air cannot go up without expanding 

 from diminished pressure ; it cannot expand without becom- 

 ing colder ; it cannot sink in temperature below the dew 

 point without condensing some of its vapor; it cannot con- 

 dense its vapor without giving out the caloric of elasticity; 

 it cannot give out the caloric of elasticity without expand- 



