• N GALVANISM AND ELECTRICIT*. ] g£ 



electrified substance, this ball only acts the part of a mes- 

 senger, or serves as an instrument to reestablish an equilib- 

 rium between the opposite states. Hence it was erroneous 

 to oppose to the theory of one io\e fluid, with the affectation, 

 of so much confidence, the phenomena of repulsion between 

 two substances negatively electrified, and the direction of a 

 needle to the same point, whether moved by a current flow- 

 ing to it, or a current escaping from it. In one case it moves 

 to get rid of the fluid received, in the other to regain that 

 which has been taken away. 



No intelligent partisan of the theory of a single fluid ever Air never cor- 

 said, that the air condenses round a substance negatively ^^^1°^ 

 electrified, or electrified" by subtraction. electrified 



minus. 



In the experiment proposed by Girault to decide between Girauit'\s ex- 

 the two theories, an experiment that has been a thousand P" nrnenUJ * 

 times made, the fluid is not transferred from one coating to 

 the other, but diffuses itself in the void space, which no 

 longer offers the resistance, on which its condensation and 

 its adhesion to substances depend : yet as in this experiment 

 the vacuum cannot form at once, the electric fluid separates 

 in succession as the air rarefies, and prevents us from observ- 

 ing whether it flow from the exterior or interior surface of 

 the bottle. For this experiment it is not necessary, to charge 

 the bottle at a machine with a plate of resin : for to charge 

 it negatively within, it is sufficient to present its outer coat- 

 ing to the conductor, while its interior coating communicates 

 with the ground, or to charge it in the usual way, present- 

 ing its hook to the cushions of a machine, the conductor of 

 which is not insulated. In electrical experiments made in 

 vacuo, the fluid that ceases to be applied is transformed in- 

 to light, traverses the receiver, and is dissipated in the air. 



I have written you insensibly a long letter, yet what I have 

 said has not been the more interesting on this account. My 

 head and my papers are filled with memorandums of fact3 

 and ideas, which my occupations do not allow me to set in 

 order, and which render me diffuse when I have occasion to 

 speak of them. 



