VOL. XLI.j PHILOSOPHICAL TKANSACTIONS. 351 



Ea-per. Q. — Dry sheep- skin transmitted the electricity, but not wlien wet, 

 though it received it then, when suspended. 



Exper. 10. — A middle supporter of packthread was again supported on one 

 side by a glass tube, and on the other by sealing-wax, and had at each end an 

 ivory ball hanging. Those balls became electrical in the same manner, and at 

 same time, as the ball at the end of the conducting spring. 



Exper. 1 1. — When a bar of oak was made use of instead of the tube, or a 

 small iron bar instead of the wax, the electricity was stopped : but when the bar 

 was thrust a little way into a glass tube, the electricity was communicated as 

 before. 



Experiment made at the Royal Society, Feb. Q, 1737-8. By the Same. 



N°454, p. 196. 



I fixed 6 iron radii, of twisted iron wire, to a brass ring, of 2 feet diameter, 

 and half an inch wide, which had a socket in the centre, by which to set it either 

 on an upright glass tube, or on a wooden pillar : then were hung on the end 

 of the 6 radii, next to the circumference, the following substances. 1. A piece 

 of resin. 2. A stick of wax. 3. An apple. 4. An ivory ball. 5. A steel ball. 

 6. A glass ball. 



Exper. 1 and 2. — I rubbed the tube, and applied it to the centre of this 

 machine, as it stood on a glass tube ; and the electricity was communicated to 

 all the suspended bodies, and the ring also ; but none of them received it, when 

 the machine stood on a wooden pillar, with its foot on the floor. 



Exper. 3. — I tied to the ends of the 6 radii as many cat-gut strings, but 

 so long as to unite together about a foot higher than the centre of the ring, 

 where they were suspended by another cat-gut string 3 feet in length, the top 

 of which was fastened to a hempen rope. Then applying the rubbed tube very 

 near the place where all the cat-gut strings joined over the ring, at which ring 

 the same bodies were suspended as before, neither the bodies nor ring re- 

 ceived any electricity. 



Note. This was done in foul weather, when the electricity does not extend it- 

 self far from the tube : but in fair weather, the electrical virtue, at the same 

 distance, reached the iron radii of the ring ; and consequently the ring and 

 bodies suspended, though the virtue was not propagated, along the cat-gut : 

 for if the tube was applied a little higher to the single cat-gut, so as the 

 effluvia, or virtue darted directly from the tube, did not reach the ring, or its 

 iron radii, then no virtue was communicated to the ring nor to the suspended 

 bodies, &c. 



