454 PHILOSOPHICAL TRANSACTIONS. [aNNO 1731. 



glass tube, as was expected, considering the difference of their lengths and 

 diameters. 



They then proceeded further, by adding so much more line, as would 

 make a return to the other end of the barn, the whole length of the line 

 being now 293 feet; and though the line was so much lengthened, they found 

 no perceivable difference in the attraction, the ball attracting as strongly as 

 before. This encouraged them to add another return ; but on begiiniing to 

 rub the tube, the silk lines broke, not being strong enough to bear the weight 

 of the line, when shaken by the motion communicated to it by rubbing the 

 tube. On this, instead of the silk, they put up small iron wire; but this 

 was too weak to bear the weight of the line. They then took brass wire, of 

 a somewhat larger size than the iron wire. This supported the line of com- 

 munication. But though the tube was well rubbed, yet there was not the 

 least motion or attraction, communicated by the ball, neither with the great tube 

 which they used, when they found the small solid cane to be ineffectual. By 

 which they were now convinced, that the success they had before, depended on 

 the lines that supported the line of communication, being silk; and not on 

 their being small, as before trial Mr. Gray imagined it might be; the same 

 effect happening here, as when the line that is to convey the electric virtue is 

 supported by packthread, viz. that when the effluvia comes to the wire, or 

 packthread that supports the line, it passes by them to the timber, to which 

 each end of them is fixed; and so goes no further forward in the line that is to 

 convey it to the ivory ball. 



Finding that the silk threads were too weak to bear many returns of line, 

 Mr. Wheler thought of another way of managing them : so that fewer returns 

 might be on each silk line ; which was by placing two other cross lines some 

 feet below the upper ones : so that every other turn of line was suspended by 

 the lower cross line. By this means there was but half the weight of line on 

 each silk of what there was, when only two cross lines were used. By this con- 

 trivance they could add a much greater length of line, without danger of break- 

 ing the silk. They then put up a line, that was ti66 feet in lengtli, by 8 re- 

 turns : then the leaf-brass being held on a piece of white paper under the ivory 

 ball ; and the tube, with the other end of the line suspended on it, being 

 rubbed for some time, the leaf-brass was attracted as manifestly as it had been 

 with much shorter lines. They then repeated the experiment with the little 

 short solid cane, and found there was somewhat of an attraction, but not near 

 so great as with the large tube. 



Though the going and returning of the electric effluvia was very surprising, 

 yet they were willing to try, how far the attractive virtue might be carried in a 



