4 PHILOSOPHICAL TRANSACTIONS. [aNNO J 735. 



times successively, only the rays were each time shorter than the former : and 

 these lights were attended with a hissing noise. The light which appears on 

 that end next the tube, when it is held obliquely to the axis of the rod, has its 

 range tending towards it. All the time he is rubbing the tube, these flashes of 

 light appear on every motion of his hand, up or down the tube; but the largest 

 flashes are produced by the downward motion of the hand. 



When several rods are laid either in a right line, or forming any angle with 

 each other ; and either touching, or are at a small distance from each other ; 

 the tube being applied to one of their ends, the farthest end of the farthest rod 

 exhibits the same phaenomena, as one single rod does. 



An experiment with the rod pointed at one end only. When the tube is ap- 

 plied to the other end, the point exhibits the same appearance, and a like effect, 

 as the rods that are pointed at each end ; but the great end of the rod, when 

 the hand or cheek is applied near it, gives but one single snap ; though this is 

 much louder than the greatest of those from the pointed end, and it gives a 

 little more pain. 



Having forged an iron ball, 2 inches diameter, and then turned and burnished 

 it; having placed it on a wooden stand with a small concave on the top, in 

 which the ball was placed: the stand being set on a cylindric glass, and the 

 excited tube being applied near the ball, a stream of light proceeded from it, 

 with a small hissing noise : but putting his finger or cheek near the ball, no 

 snapping nor pain was felt ; yet a very bright light appeared. 



The rod, of 4 feet long, being placed on a stand, having a cross arm, with a 

 groove in it, to receive the rod ; and then the stand being placed on the glass 

 cylinder, they were set at such a distance, as that one of the points of the rod 

 might just touch the ball over against its centre ; then going to the other end 

 of the rod with the excited tube, he applied it as usual ; when he came to the 

 ball, the hand or cheek being near it, caused a loud snap, compared to those 

 made by the points of the rods, and the pain of pricking or burning was more 

 strongly felt ; the light was also brighter and more contracted. The rod being 

 then placed with its point at an inch distance from the ball, and applying the 

 rod as before, then touching the ball with his finger, there not only appeared a 

 light on the ball, but there also proceeded a pencil of light from the point of 

 the rod, after the same manner as when the experiments were made with the 

 rods only. 



The following experiment was made with the 4-foot rod, and a brass plate 4 

 feet square. This was placed on a stand, so that the plate stood perpendicular, 

 the stand being set on the cylindric glass ; then the rod with its stand and glass 

 was set in such a manner, that one point of it was about an inch from the centre 



