406 FHILOSOPHICAL TRANSACTIONS. [anNO I759. 



to separate them ; for if that happens in pulling them off, all the electricity es- 

 capes. The best way is to put the hand between the leg and the stockings, and 

 so push them off together. Nothing more remains to be done, than to pull 

 them asunder ; for then they both exhibit a degree of electricity, which when 

 at the highest is really surprising. 



Mr. S.'s first trials had by accident been made with black silk stockings; 

 but afterwards making trial in like manner with white ones, he was surprized 

 that they produced no electricity. He took a pair of white silk stockings, and 

 having warmed them at the fire, put them both on the same leg. After re- 

 maining about 10 minutes, he took them off, and pulled them asunder, but dis- 

 covered no signs of electricity in either. He did the same with a pair of black 

 silk, but to no other effect. He then proceeded to the decisive trial : he put a 

 black and white stocking on his leg, and wore them likewise 10 minutes; and 

 in return had the satisfaction of observing, on their being pulled asunder, that 

 each of them had acquired a stronger degree of electricity than he had before 

 seen : they were inflated so much, that each of them showed the entire shape 

 of the leg, and at the distance of a foot and a half they rushed to meet each 

 other. He went through the same experiment with worsted stockings, and found 

 that, as in silk, nothing but the combination of black and white produced elec- 

 tricity. As I had often experienced the power of electricity in the combination 

 of black silk with white worsted stockings, there remained only to try that of 

 white silk with black worsted, which answered as he expected, and seemed to 

 complete the demonstration. 



Paper ii. — On the Electricity of black and white Silk. 



By a great number of experiments Mr. S. observed that the electricity pro- 

 duced between black and white silk, is stronger than that between silk and 

 worsted of those different colours, and a great deal stronger than that between 

 worsted and worsted : the last is so weak, except in time of frost, or when a 

 sharp north-east wind blows, that though the effects are always of the same na- 

 ture, yet they are sometimes so languid as to be scarcely perceptible. He there- 

 fore confines himself in this paper, to what is observable with regard to the 

 electricity between black and white silk only. It is proper to mention another 

 circumstance : having found it troublesome to electrify the stockings, by putting 

 them as often on his leg as was requisite in making experiments, lie quitted 

 that method entirely ; and satisfied himself with the degree of electricity which 

 is excited in the stockings by drawing them on the hand : and this is to be un- 

 derstood with regard to all the following experiments and observations, unless 

 when otherwise expressed. The electricity thus produced is not equally power- 

 ful with that which is excited by means of the leg ; but it is sufHciently strong 

 to answer all the purposes in view ; and is attended with this advantage, that 



