tfic'ir Production, Suspension, and Destruction. 353 



much of the inquirv^ that is to follow, were it not that it 

 leaves us quite in the dark, both as to the cause of the variety 

 so readily observable in clouds, and their long suspension, 

 Jiot to insist on several facts contained in the former part of 

 this paper, which would then remain unaccounted for. 



The operation of one simple principle would produce an 

 effect at all times tinijhrm, and varying only in degree. We 

 should then see no diversity in clouds but in their magni- 

 tude, and the same attraction that could bring minute drops 

 of water together through a considerable space of atmo- 

 sphere in a few minutes, ought not to end there, but to effect 

 their perfect union into larger, and finally into rain. 



In admitting the constant operation of electricity, which is 

 sometimes so manifestly accumulated in clouds, upon their 

 forms and arrangement, \\'e shall not much overstep the limits 

 of experimental inquiry, since it has been ascertained by se- 

 veral eminent philosophers, that " clouds, as well as rain, 

 snow, and hailj that fall from them, are ahnost always elec- 

 trified *." 



An insulated conductor formed of solid matter retains 

 the charge given to it so much the longer, as it is more 

 nearly spherical, and free from points and projecting parts. 

 The pai'ticlcs of water, when charged, appear to make an 

 effort to separate from each other, or, in other words, bd^- 

 come mutually repulsive. Moreover, when a small con- 

 ducting substance is brought within the reach of a large 

 . one similarly electrified, the latter, instead of repelling, will 

 throw the small one into an opposite state, and then attract 

 it. From these and other well-known facts in electricity' it 

 would not be difficult to demonstrate, that an assemblage of 

 particles of water floating in the atmosphere, and similarly 

 electrified, ought to arrange themselves in a spherical ag- 

 . grcgate, into which all the surrounding particles of water 

 should be attracted (within a certain distance) at the same 

 time tliat the drops composing such aggregate should be 

 absolutely prevented from unitmg with each other during 

 the L'ijiidibrium of their clectricily . 



To apply this reasoning to the formation of the cunmlus, 

 we may, in the first place, admit that the commencement 

 of distinct aggregation, in the descending particles of water, 

 is due to their nmtual attraction, by virtue of which small 

 bodies, floating in any medium, tend to coalesce. The 

 uiasses thus I'ormed, however, often increase more rapidly 

 than could -be expected from the effect of simple attraction 



" Cavallo. Complete Treati<^c on Electricity, vol. i. p. 74- 



Z S exercised 



