HUTCHISON'S OBJECTIONS, WITH REPLIES. 461 



tending simultaneously over a surface of many hundred 

 miles in diameter, the wind at the surface of the earth, over 

 the whole extensive tract of country where the rain fell, is 

 said to have been blowing with great, or considerable, force,, 

 towards the centre of where the rain was falling; that there 

 it fell in greatest quantity ; and there, and there only, so far 

 as I understood your report, the upward vortex of air ex- 

 isted. Now I am at a loss to know how any rain should 

 have fallen, agreeably to your theory, beyond the bounda- 

 ries of your supposed upward vortex of air. If clouds and 

 rain are produced only by an upward vortex of air, how 

 did it happen, on these occasions, to rain simultaneously for 

 several hundred miles east, west, north and south, of the 

 supposed upward vortex ? ! 



4th. If your theory supposes that an upward vortex of 

 air exists over the whole extent of surface where clouds are 

 forming, or rain falling, the clouds, when viewed from the 

 surface of the ground underneath, should always be sta- 

 tionary, though the wind be blowing underneath with great 

 velocity, and in one determinate direction. Now in this 

 country, (and I suppose it must also be the case in Ameri- 

 ca,) when the wind blows with great or considerable velo- 

 city in one determinate direction, and clouds are forming or 

 rain falling, the clouds are always moving in the same 



1 Here again the doctrine taught by me appears to have been entirely mis- 

 understood or overlooked. 



The doctrine I have taught in all my essays is, that as soon as the air 

 around a cloud comes in under its base, it is under less pressure, and begins 

 to ascend, not, of course, perpendicularly, but obliquely. It is only in the 

 centre where the motion can be perpendicular ; and so far from the greatest 

 quantity of rain falling always in the centre of the storm, it sometimes hap- 

 pens that the perpendicular velocity of the air is so great, that the drops of 

 rain are not permitted to fall there, but are carried up to a great height, and 

 then spread outwards towards the borders of the storm, and fall there, where 

 the upward motion is not sufficient to overcome gravity, and even beyond the 

 borders of the upmovmg current where the barometer stands above the mean. 



