HUTCHISON'S OBJECTIONS, WITH REPLIES. 469 



when the atmospheric current rises in surmounting hills,) 

 is ever, in any instance, a cause of the formation of clouds, 

 or of the descent of rain, in temperate or cold latitudes. 

 And from comparing the extreme smallness of the fluctua- 

 tions and range of the barometer in intertropical climates, 

 where the rains are heaviest, with its great fluctuations and 

 range in temperate latitudes, where the amount of rain is 

 comparatively very small, it is obvious, that if clouds and 

 rain be occasioned by upward vortices of air, barometric 

 fluctuations must be either wholly occasioned, or at all 

 events much assisted, by some other cause. 



If it was formed either by an upmoving column of warm air, or by a down- 

 moving column of cold air, mingling with the air through which it passed, 

 then would the cloud appear something in the form of a hollow cylinder, for 

 the central parts of the ascending or descending column could not mingle 

 with the surrounding air. Now, the central parts of the cloud seem to be 

 much the densest, if we can form any judgment from the blackness of the 

 base, just as it should be on my principle, but not at all on the Huttonian. It 

 will not surely be contended that air can be mingled to any extent sufficient 

 to produce large clouds by different currents meeting each other on the same 

 horizontal level, and even if it should, it could not be imagined how a cloud 

 in the shape of a sugar loaf could be formed on this principle, with a flat 

 base always just about as many hundred yards high as the temperature of the 

 air is above the dew point in degrees of Fahr. at the time the cloud is forming, 

 which exactly corresponds with the height of the base, on the supposition that 

 the air does move up from the surface of the earth into the base of the cloud. 

 Besides, if it should be found, as is highly probable, that the upper portions 

 of the atmosphere always contain more caloric to the pound than the lower, 

 from the caloric given out there by the vapor condensing into cloud, the 

 doctrine of mixture forming a cloud, would have to be given up on this 

 ground alone. 



I have now attempted to answer all the objections which have been brought 

 against my theory by a gentleman of highly cultivated and acute mind, one who 

 has himself written one of the best treatises on meteorology extant, and also 

 a very late work on Unexplained Phenomena, which I do not hesitate to say 

 manifests great originality and power of thought, though I am not yet pre- 

 pared to subscribe to all his views. 



If I have not been entirely successful in answering, to the satisfaction of 

 the candid reader, all the objections, I think it will be but fair to set down 

 the failure, not to the weakness of the theory, but to the want of skill in the 



