442 Additional Notes. 



fluids, which operate on each other, and on other bodied,, 

 upon meckanical principles. They suppose that these are 

 two distinct, positive, and active powers, which equally and 

 strongly attract and condense each other; that they exist to- 

 gether 'in all bodies, in their natural state, conjoined; but 

 that their electric signs, or what we call electricity, only be- 

 come sensible in consequence of the separation of these two 

 powers. That, while united, they are latent and invisible; 

 but when separated they become immediately visible and ac- 

 tive. These two fluids or powers are called Vitreous and 

 Besinoiis electricities. — See Eeles's Philosophical Essat/s^ 

 1771, and Adams's Lectures. 



There are others who explain the phenomena of electricity 

 upon chemical principles. They also believe in the existence 

 of two distinct and positive fluids ; but instead of a mechanical 

 operation, they consider all their sensible eflPects as arising 

 from chemical affinity and union. The following theory of 

 Dr. Darwin may serve as a specimen of chemical electricity. 

 — See Temple of Nature, Additional Notes, p. 46. 4to. 

 Lond. 1803. 



1. There are two kinds of electric ether, which exist ei- 

 ther separately or in combination. That which is accu- 

 mulated on the surface of smooth glass, when rubbed with 

 a cushion, is here termed vitreous ether ; and that which is 

 accumulated on the surface of resin, or sealing-wax, when 

 rubbed in like manner, is here termed resijious ether; and a 

 combination of them, as in their usual state, may be termed 

 neutral electric ethers* 



2. Atmospheres of vitreous, or of resinous, or of neutral 

 electricity, surround ail separate bodies, are attracted by 

 them, and permeate those which are called conductors, as 

 metallic, aqueous, and carbonic substances; but will not 

 permeate those which are called non-conductors, as air, glass, 

 silk, resin, sulphur. 



3. The particles of vitreous ether strongly repel each other, 

 but attract the particles of resinous ether, and vice versa. 

 When the two electric ethers unite, a chemical explosion oc- 

 curs, in some respects like that of gunpowder, light and heat 

 are liberated, and rend or fuse the bodies which they occupy. 



4. Glass holds within it, in combination, much resinous 

 electric ether, which constitutes a part of it, and which more 

 forcibly attracts vitreous electric ether from surrounding 

 bodies, which stands on it, mixed with a less proportion of 

 resinous ether, like an atmosphere, but cannot unite with the 



