420 Mr. Sturgeon's Description of 



sequent repulsion or deflection of the clouds is produced. 

 This electric force now operating in conjunction with the 

 wind, gives the cloud a new direction of motion, and urges it 

 over a tract of country composed of better conductors, which 

 are more susceptible of being transpierced by the electric 

 matter than those from which the cloud was deflected. 

 Hence it is that electric storms are more frequent and more 

 violent over marshy lands, rivers, &c, than over drier and 

 more elevated tracts of country*. 



These causes operated in a very beautiful manner in giving 

 direction to the storm on Saturday evening. The principal 

 group of clouds, as before stated, never reached Shooter's 

 Hill, but was carried over the low wet lands, on the other 

 side, to the Thames ; and the foremost clouds were taken to 

 the other side of the river, and over a considerable tract of 

 the Essex marshes. At this period another direction was 

 given to the storm, and the new combination of forces urged 

 it in the direction of the river, a route which electric storms 

 visiting this neighbourhood very frequently take. 



Its progress down the river was exceedingly slow, owing, 

 as I suppose, to the wind (though much slackened before this 

 time) being more directly opposed to it. I had been floating 

 an electric kite in the Artillery Barrack-field during the 

 transit of that part of the storm which passed over Woolwich. 

 I had got completely wet with the heavy rain which fell du- 

 ring the time ; notwithstanding which, the unusual fineness of 

 the lightning which was playing over the river and marshes 

 induced me to pursue it with my eye, when, from its distance, 

 I could no longer explore the theatre of its resplendent exhi- 



the present year, on the top of some of the high hills in Westmoreland 

 and in the North Riding of Yorkshire ; and in every case I have found the 

 atmosphere positive with regard to the ground. In most of these cases, 

 the stations at the tops of the hills were higher than the place of the 

 kite when the experiments were made at the lower ones. 



I have floated three kites at the same time, at very different altitudes, 

 and have uniformly found the highest to be positive to the other two, and 

 the centre kite positive to that which was below it; consequently the 

 lowest one was negative to the two above it ; but still it was positive to 

 the ground on which I was standing. I have made more than twenty ex- 

 periments of this kind, and the results (with the exception of electric ten- 

 sion) were invariably the same; showing most decidedly that the atmo- 

 sphere in its undisturbed electric state is more abundantly charged than 

 the earth, and, as far as I have been able to explore it, still more abund- 

 antly in the upper than in the lower strata. 



* Immense tracts of flat country frequently become charged in the same 

 manner and from the same cause as ranges of hills are charged ; but the 

 repulsive force from such places is directed vertically, and not so directly 

 opposed to the horizontal direction of the cloud's motion as that pro. 

 ceeding from the side of a high hill. 



