58 Notices respccl'mg New Books, 



negatively electrified, or in a natural state, to enable It to bear 

 the burden of an accumulated load. In a machine it will be ob- 

 served, that the rubber and glass disturb the equilibrium of elec- 

 trical quiet. The chain and cushion, froni the air and earth, 

 supply the loss of the electric fluid, imparted by the cylinder to 

 the positive conductor, which rushing thence to surrounding 

 atoms, returns to the source whence it came. 



" To illustrate these remarks, observe by way of comparative 

 analogy, the operations of a common pump. The water is forced 

 \ip from the well by the hantlle and hand, and passing through the 

 spout falls by the power of gravity instantly to the earti). A re- 

 servoir may, for u season, contain a part ; but when a vessel is 

 over-filled, the superabundant water passes from the inside to the 

 outside, and then returns again to its native depositary. But when 

 a vessel is not over-filled, the water will be retained in it for some 

 time, till it is evaporated ; and then descends again in fruitful 

 showers on the parched ground. So it is with the Leyden jar, 

 when charged with the electric fluid 3 but it acts with this diffe- 

 rence, that its outside is in a deficient or attractive state, while 

 its inside is overloaded with a propelling fluid, and the whole of 

 its contents are discharged at once. 



" Gravity can make but humble claims on the electrical prin- 

 ciple, and even these are granted rather as a boon than a right, 

 for the equilibrium of nature is its grand bminess and end. The 

 Franklinian theory, therefore, has been found so agreeable to the 

 analogy of nature, that it has been generally adopted. Like the 

 Newtonian system, the simplicity of the principie gives dignity 

 to the doctrine ; while it supplies the best key to many dark and 

 otherwise inexplicable points in philosophy, physiology , and pa- 

 thology. 



" Tlie theory of two di stinct fluids originated with Du Faye, an 

 eminent French philosopher contemporary vvith Franklin, which 

 he deduced from his practical researches into the different pro- 

 perries of vitreous and resinous electrics excited by friction. As 

 he found the electricity developed by the positive and negative 

 electrics was dissimilar in its states, he c«ncluded they were di- 

 stinct fluids, though possessing the same nature and residing to- 

 gether in all bodies. From their being separated in conductors, 

 as well as from their reciprocal efforts to unite again, it was sup- 

 posed the truth of this theory was made apparent. This opinion 

 was stronglv supported by Symner, who had philosophized so in- 

 geniously on the subject, that, though it was contrary to the known 

 laws of electricity, be gave to the error an air of plausibility. 



'•' This opinion, however, is now as much exploded as the as- 

 tronomical systems of Ptolemy or Tycho Brahe. The double 

 current of these electricians imposed as much labour on the elec- 

 tric 



