460 PHILOSOPHICAL TRANSACTIONS. [aNNO 1731. 



than to about 6 inches. The boy's hands being extended nearly horizontal, 

 Mr. Gray placed a small stand with leaf-brass under each hand, and the large 

 stand, furnished as the others, under his face ; when the excited tube being 

 held near his feet, there was an attraction by his hands and face at the same 

 time. Mr. Gray then gave him the top of a fishing rod to hold in his hand ; 

 there was a ball of cork stuck on its small end, under which the leaf-brass being 

 laid, and the tube rubbed and held near his feet, tlie ball attracted the leaf-brass 

 to the height of 2 inches ; and very vigorously repelled and attracted it for 

 several times together. 



April 21, Mr. Gray repeated the experiment on the boy; and now he at- 

 tracted much stronger than at the first : the leaf-brass rose to his face at the 

 height of more than 12 inches. He then gave the boy to hold in each hand the 

 tops of 2 fishing rods, with a ball of cork on each of their small ends ; then a 

 small stand being set under each ball, with the leaf-brass on it, the tube being 

 rubbed and held near his feet, both the corks attracted and repelled together 

 strongly. The length of each of the poles was about 7 feet. Then the boy 

 was laid on his left side, and a fishing rod, of near 12 feet in length, given him 

 to hold with both his hands ; there was a small ball of cork at the end of the 

 rod, that was an inch and three quarters in diameter : then every thing being 

 prepared, the tube held near the boy's feet, the cork ball attracted and repelled 

 the leaf-brass forcibly to the height of at least 2 inches. 



N. B. That when Mr. Gray speaks of holding the tube near the boy's feet, he 

 means over against the soles of his feet ; and when near his head, he means the 

 crown of his head: for, when the tube is held above, or over his legs, the at- 

 traction is not so strongly communicated to the other parts of his body. 



By these experiments it is seen that animals receive a greater quantity of 

 electric efHuvia ; and that tiiey may be conveyed from them several ways at the 

 same time to considerable distances, wherever they meet with a passage proper 

 for their conveyance, and there exert their attracting power. 



In these experiments, besides the large stand abovementioned, Mr. Gray 

 used two small ones, the description of which is as follows : their tops were 3 

 inches diameter ; they were supported by a column of about a foot in height ; 

 their bases of about 44^ inches; they were turned of lignum vitas; their tops 

 and bases made to screw on for conveniency of carriage ; on the tops was pasted 

 white paper. When the leaf-brass is laid on any of these stands, he finds it is 

 attracted to a much greater height than when laid on a table ; and at least 3 

 times higher than when laid on the floor of a room. 



June 20, 1730, Mr. Gray made the following experiment, showing that the 

 attraction and repulsion is as strong, if not stronger ; and that the effluvia may 



