198 THE LEYDEN PHIAL. 



If, therefore, we place an electric upon any of those 

 non-conducting bodies, the air around being well dried, 

 we are enabled to gather a large quantity of the force 

 for the production of any particular effect. Taking ad- 

 vantage of this fact, arrangements are made for the 

 accumulation and liberation at pleasure of any amount 

 of electricity. 



A Ley den phial, so called from its inventor, Muschen- 

 brock, having resided at Leyden, is merely a glass bottle 

 lined within and without, to within a few inches of the 

 top, with a metal coating. If a wire or chain, carrying 

 an electric current, is allowed to dip to the bottom of 

 the bottle, the inner coat of the jar becomes charged, 

 or gathers an excess, whilst the outer one is in its natural 

 condition one is said to be in a positive, and the other in 

 a negative state. If the two coatings are now connected 

 by a good conductor, as a piece of copper wire, passing 

 from one to the other, the outside to the inside, a dis- 

 charge, arising from the establishment of the equili- 

 brium of the two coatings, takes place ; and, if the con- 

 nection is made through the medium of our bodies, 

 we are sensible of a severe disturbance of the nervous 

 system. 



The cause of the conducting and non-conducting 

 powers of bodies we know not ; they bear some relation 

 to their conducting powers for caloric ; but they are not 

 in exact obedience to the same laws. When we consider 

 that resin, a comparatively soft body, in which, conse- 



duct electricity of this low intensity; there are some which 

 conduct it and are not decomposed ; nor is fluidity essential to 

 decomposition. 



" There are but two bodies (sulphuret of silver and fluoride 

 of lead) which, insulating a voltaic current when solid, and con- 

 ducting it when fluid, are not decomposed in the latter case. 



" There is no strict electrical distinction of conduction which 

 can as yet be drawn between bodies supposed to be elementary, 

 and those known to be compounds.'' 



