Proceedings of the British Association. 41 



city, being insulated, forms an atmosphere around each particle of 

 vapor : which surcharge of electricity not only suspends the va- 

 por by its lightness, but also repels the neighboring particles of va- 

 por, and prevents the formation of rain ; and on the removal (by 

 any cause,) of the electricity including the vaporous particles, 

 the repulsion is removed, and the particles of vapor then attract 

 each other, and form rain. Another cause of the formation of 

 rain he believes to be the pressure of gravitation : thus if a cloud 

 begins to form, the accumulation of vapor is on every side, but 

 especially from above, and clouds are often seen piled to a great 

 height ; now each particle of vapor on forming the cloud, must 

 have its extra charge of electricity over the particles of the cloud 

 instantly dispersed through the whole mass ; would become of 

 the same density as the mass, and would take its level according 

 to its density in the atmosphere, if not prevented by the space 

 being occupied, and would therefore press on the vapor below it ; 

 and although the repulsion of the particles of vapor be sufficient 

 to prevent the formation of rain at the edges and thinnest parts 

 of the cloud, the pressure at the greatest depths of the cloud may 

 be sufficient to overcome the repulsion and form rain. Concus- 

 sions, he conceives, such as those of thunder, would aid the pro- 

 cess, and cause heavy rain. He entered into proof of these po- 

 sitions in the papers. They account in his opinion, for the fact 

 observed by Prof. Phillips, that more rain is received in gauges 

 near the ground than in those higher up. He conceives a test of 

 this theory may be had by raising conductors to clouds by the 

 aid of balloons, discharging their electricity : and thus he thinks 

 rain might be produced exactly when needed. His views re- 

 specting the cause of the Aurora and of magnetism are conse- 

 quences of his theory of vapor and rain. The particles of vapor 

 most expanded on rising from the earth, would carry with them 

 a greater quantity of electricity, and would be buoyed up by the 

 electricity to a greater height in the air than that which rises in a 

 less expanded state. Thus, in the tropics, through the action of 

 a vertical sun, vapor would rise to a great height with a great 

 accumulation of electricity : this vapor, carried by the superior 

 trade winds toward the poles on each side, there would be a con- 

 stant circulation of electricity, a continual rising of vapor, espe- 

 cially in the tropics, carrying a great accumulation of electricity 

 to the coldest parts of the earth, where the electricity again es- 



Vol. xLi, No. 1.— April-June, 1841. 6 



