THUNDER AND LIGHTNING. 



properly adapted to the purpose, and reduced to its natural state 

 when placed horizontally on the ground, will show a sensible 

 divergence when raised to the level of the eyes. 



8. To ascertain the electrical condition of strata too elevated 

 to be reached by a fixed conductor, the extremity of a flexible 

 wire, to which a metallic point is attached, is connected with a 

 heavy ball, which is projected into the air by a gun or pistol, or 

 to an arrow projected by a bow. The projectile, when it attains 

 the limit of its flighf, detaches the wire from the electroscope, 

 which then indicates the electrical state of the air at the highest 

 point attained by the projectile. 



9. The vast quantities of electricity with which the clouds are 

 sometimes charged, were rendered manifest in a striking manner 

 by the well-known experiments made by means of kites by Romas 

 in 1757. The kite, carrying a metallic point, was elevated to the 

 strata in which the electric cloud floated. A wire was connected 

 with the cord, and carried from the pointed conductor borne by 

 the kite to a part of the cord at some distance from the lower 

 extremity, where it was turned aside and brought into connection 

 with an electroscope, or other experimental means of testing the 

 quantity and quality of the electricity with which it was charged, 

 llomas drew from the extremity of this conducting wire not only 

 strong electric sparks, but blades of fire nine or ten feet in length, 

 and an inch in thickness, the discharge of which was attended 

 with a report as loud as that of a pistol. In less time than an 

 hour, not less than thirty flashes of this magnitude and intensity 

 were often drawn from the conductor, besides many of six or seven 

 feet and of less length. 



10. It has been shown by means of kites thus applied, that the 

 clouds are charged some with positive and some with negative 

 electricity, while some are observed to be in their natural state. 

 These circumstances serve to explain some phenomena observed 

 in the motions of the clouds which are manifested in stormy 

 weather. Clouds which are similarly electrified repel, and those 

 which are oppositely electrified attract each other. Hence arise 

 motions among such clouds of the most opposite and complicated 

 kind. While they are thus reciprocally attracted and repelled in 

 virtue of the electricity with which they are charged, they are 

 also transported in various directions by the currents which pre- 

 vail in the atmospheric strata in which they float, these currents 

 often having themselves different directions. 



11. Such appearances are the sure prognostics of a thunder- 

 storm. Clouds charged with contrary electricities affect each 

 other by induction, and mutually attract, whether they float in 

 the same stratum or in strata at different elevations. When they 



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