VOL. LXVlII.j PHILOSOPHICAL TRANSACTIONS. 437 



appears, that the charged cloud would continue striking to the natural cloud, 

 and that would again part with it silently, hy means of the point, without 

 striking on it till the charged cloud is nearly exhausted. When we see a cloud 

 striking into another cloud several times together, we conclude from all the 

 known laws of electricity, that the cloud which first received the stroke must 

 have discharged part or the whole of what it received before it could receive 

 another stroke. 



In the 20th experiment we find, that though the moveable artificial cloud was 

 in great motion, receiving and discharging its electric fire on the ball, that, on 

 taking away the ball, and putting the point in its place, the artificial storm 

 immediately ceased. In the 21st experiment, where the point was on a stick of 

 wax, with separations in the metallic communication with the earth, we find 

 that, even in that situation, the stroke on the point was very small to what 

 it was on the ball with a good communication, great part of the electric fire 

 visibly passing off as the cloud approached the point; and when the metallic 

 communication was made complete by hanging on the chain, it then ceased 

 striking to the point. 



Exp. 23. The tube before called the moveable artificial cloud, from its 

 moving very easily on its axis, was, by means of 2 screws now fixed, immove- 

 able, with the ball at one of its ends above the ball c at the end of the artificial 

 cloud, at the height of 3 inches; and underneath the ball, at the other end, 

 was placed the stand with the point, at the distance also of 3 inches. The 

 artificial cloud was then charged, and an electric spark struck from the ball c at 

 the end of it to the ball of the now fixed cloud above it, and at the same instant 

 struck from the ball at the other end to the point at 3 inches. 



Exp. 24. The tube used in the last experiment (which Mr. N. now again 

 calls the moveable artificial cloud from its being made again to move freely on its 

 axis) was placed exactly in every respect as in the last experiment; the only 

 difference was, that it could now move easily on its axis, whereas in the last 

 experiment it was fixed immoveable at the distances: on charging the artificial 

 cloud, the moveable artificial cloud, instead of receiving a spark, and discharging 

 it on the point, as in the last experiment, was now attracted down to the artifi- 

 cial cloud there remaining, not striking to the point, or returning to it so long 

 as the artificial cloud continued to be charged. 



Observation. — By the 23d experiment we see, that if our cloud is fixed at a 

 certain distance between the artificial cloud and the point, the fixed cloud, at 

 the instant it receives the electric spark, directly discharges it again on the point. 

 But in the 24th experiment, where there is no other alteration than making the 

 cloud moveable on its axis, the distances being exactly the same, the end of the 

 cloud then recedes from the point and will not strike to it. This 24th experi- 



