468 METEOROLOGY. 



closed it at tlie distance at which the straws began to diverge. I now 

 tested with an essayer the nature of the electricity of the electrometer. 

 I found that if the electrified sphere was positive, the electricity of the 

 electrometer was also positive ; but if the sphere was electrified nega- 

 tively, such also was the electricity of the electrometer. From this 

 extreme point, on carrying the electrometer toward the sphere, I saw 

 the tension always continue to increase without any change occurring 

 in the species of electricity. An electrified solid then has around it an 

 electric atmosphere of the same name. We should not confound, there- 

 fore, the distribution of the electricity i^resented by an isolated solid con- 

 ductor at its surface, submitted to the influence of an electrified body, with 

 the distribution of the electricity presented by the ethereal space sur- 

 rounding that electrified body. This difference I demonstrated in all 

 its particulars and circumstances in my memoir entitled "New experi- 

 ments regarding the origin of atmospheric electricity and the electro- 

 static induction of the isolated solid conductors of Zantedeschi." * 



I arrived at the same result bj^ causing an artificial shower to fall from 

 a certaio licight, which shower I electrified positively and negatively in 

 succession, by means of my electrical machine, for the two electricities. 

 The electrometer placed at a distance from the falling rain, which 

 scarcely gave signs of tension, and which was next advanced to the 

 place where it was raining, nmnifested an increasing tension, without 

 yielding any signs of a changed electricit}'. 



The following is a description of the experiment: A car was constructed 

 with four wheels, which moved upon two threads stretched horizontally 

 like the two lines of a railroad. The wheels as well as the threads were of 

 gum-elastic, in order perfectly to isolate the car suspended by bodies com- 

 monly recognized as conductors. The vertical walls of the car and the hor- 

 izontal floor were formed of conducting substances, but the floor was perfor- 

 ated throughout in order to give passage to a kind of artificial rain, 

 when the cavity of the car was filled with water. At one end the floor 

 of the car communicated by means of a conducting-wire with the 

 electric machine, which, when charged positively, electrified positively 

 the isolated car with the water which it contained, and, charged nega- 

 tively, charged with negative electricity the aforesaid car and the water 

 contained in it. Examining with an electrometer the kind of electricity 

 of the falling rain, I have found that it was of the same nature with that 

 of the electric machine, that is to say, positive if I had used the positive 

 electricity of the machine, and negative if I had employed its negative 

 electricity. Having assured myself of this result, I proceeded b^' means 

 of an isolating thread of silk or gum-lac attached to the other end of the 

 floor to bring the hjdrometeoric electrical car into tbe proximity of a 

 straw-electrometer. These straws always diverged more in proportion 

 as the distance from the fiilliug rain diminished, without, however, 



* Atcneo Italiano, Vol. II, p. 339/priDted. at Paris by Victor Masson, 18fe4, and at Ven- 

 ice by G. Autouelli, 1854. 



