VOL. LI.] PHILOSOPHICAL TKANSACTIONS. 405 



XXXn. New Experiments and Observations on Electricity. By Robert Sym- 



mer, Esq. F. R. S. p. 340. 

 Paper i. — On the Electricity of the Human Body, and the Animal Substances 



Silk and Wool. 



Mr. S. had for some time observed, that on pulling off his stockings at even- 

 ing, they frequently made a crackling or snapping noise ; and in the dark he 

 could perceive them to emit sparks of fire ; and in weather favourable for elec- 

 trical experiments, those appearances were more remarkable than at other times. 

 He mentioned this observation to several friends, some of whom likewise had 

 often perceived the snapping, and the emission of fire from their stockings on 

 pulling them off, especially in the winter evenings : but he could not hear of 

 any one who had taken this phenomenon into consideration in a philosophical 

 way. 



His first endeavour was to discover what sort of stockings was most proper to 

 produce electricity. To determine this, he tried single stockings of different 

 kinds, viz. thread, cotton, silk, and worsted, putting them on, and wearing 

 them some time. On pulling them off, he could perceive nothing of electricity 

 in the thread or cotton, and no remarkable degree of it in the silk and 

 worsted. For whatever electricity these latter single stockings acquire by fric- 

 tion or otherwise, they immediately lose on being separated from the leg : if any 

 electric virtue remains, it is no more than what belongs to it as an electric 

 substance ceasing to be excited ; and it is in so small a degree, as in the present 

 case not to merit attention. In general, when Mr. S. speaks of the electricity 

 in question, he means such a power of electricity as is obvious, and perceptible 

 to the senses ; so that the stocking, after being taken off, should appear more 

 or less inflated ; throw out an electrical wind to be felt by the bare leg ; attract 

 or repel another stocking visibly ; and, on the touch, snap and emit, or receive 

 electrical fire. 



Mr. S. next proceeded to try the effect of 2 stockings on one leg. This he 

 did with 2 of thread, cotton, worsted, and silk successively ; but this produced 

 no electrical appearance more than before. He then combined them one with 

 another, and, running through all the different changes, found that none of 

 those he then made use of exhibited visible proofs of electricity, except the silk 

 and worsted together ; and there indeed the electric power appeared remarkably 

 strong. It seemed to be a matter of indifference whether the silk or the worsted 

 was uppermost, the combination of the two was what he judged to be essential. 



A circumstance to be carefully attended to, is the manner in which the stock- 

 ngsareto be taken off; for as to the putting of them on, it is a matter of in- 

 difference how that is performed. In taking them off, care must be had not 



