British Association for the Advancement of Science. 105 



commenced at S. W. and then very gradually moved round a 

 little more westward. It was by careful examination of the 

 records of these two instruments that I arrived at the view I ven- 

 tured to take of this storm, and the evidence I have collected 

 from various parts of the country concerning it, strongly confirms 

 me in the opinion I have taken of it. Many violent storms fol- 

 lowed in the wake of this extraordinary hurricane, but I have not 

 attempted to investigate these, as the main storm would have 

 thrown the atmosphere into so disturbed a state, that it would be 

 very likely to produce minor eddies, gusts, &c. 



Prof. Stevelly observed that so long ago as 1834, at the Edin- 

 burgh meeting, he read a paper in which he attempted to explain 

 and account for, on well-established principles, the four leading 

 meteorological phenomena, — cloud, rain, wind, and hail. He 

 gave reasons for rejecting the vesicular hypothesis as to the con- 

 stitution of cloud, chiefly because no causes were known to exist 

 adequate to the production of vesicles, and capillary attraction 

 would tend to prevent it ; and adopting the view of solid spheri- 

 cles, he showed that mere diminution of size would be suflicient 

 to account for their suspension, as even globules of platina could 

 be so reduced in size and suspended in such a manner as to de- 

 scend at any given velocity, however small ; adding to this the 

 fact that electrical atmospheres to the globules, by repelling the 

 air on all sides from the spherule of water, would virtually enlarge 

 the bulk, without adding to the weight of the drop, and thus aid 

 the suspension. Next, as to the formation of cloud ; when a 

 portion of cloud was once formed in air, loaded with vapor in the 

 elastic state, the instant effect was a diminution of tension, and a 

 fall of temperature in that spot ; air would then rush in on all 

 sides, but air loaded with vapor, rushing into a void will form 

 cloud ; more cloud would, therefore, be formed, and the causes 

 again put into operation for the formation of more, and this, (as 

 he called it,) secondary formation of cloud, would go on with 

 greater rapidity the more the air was loaded with vapor, and along 

 whatever course the air so loaded by the growing of the cloud 

 would advance ] in the mean time, the air rushing in to fill up the 

 comparative void, would establish, when the causes were strongly 

 in operation, progressive whirls, such as those described by Mr. 

 Redfield and Col. Reid, on the same principle that water while 

 going on along a course, if let out by a hole in the bottom, forms 



Vol. xxxviii, No. 1.— Oct.-Dec. 1839. 14 



