284 On the Transmission of Electricity through Fluids. [April, 



the surface of the board ; but on repeating the experiment with 

 a tube of water, the powder was inflamed, and the wafers 

 remained without any perceptible motion. This experiment led 

 me to suppose, that a sufficient degree of heat under each cir- 

 cumstance was produced by the electrical fluid to inflame the 

 powder ; but when it passes through good conductors, the air is 

 so suddenly and violently expanded, that the powder is scat- 

 tered before it can be inflamed, as is the case with some of the 

 grains when a musket is let off (for if it be fired over snow, a 

 considerable portion of unconsumed powder will be perceived), 

 but water being a less perfect conductor than the metals, by 

 opposing a resistance to the passage of the electrical fluid, 

 retards its velocity, and thus prevents the sudden expansion of 

 the air, which would have scattered the powder before inflam- 

 mation could have taken place. 



This theory explains the circumstance of the charge having 

 no effect upon the wires when transmitted through a tube of 

 water. It is well known that intensity of charge is of the great- 

 est importance in the fusion of wires. Now as intensity is 

 velocity, it must follow, if the velocity of a charge be retarded, 

 the intensity must be diminished ; and hence no experiment 

 requiring intensity of charge can be performed when the water 

 tube forms part of the circuit. 



If the tube be filled with other fluids, it will be found that the 

 nearer the transmitting medium approaches to a good conductor, 

 the greater will be the expansive effects ; and as the expansive 

 effects increase, the difficulty of inflaming the powder will 

 increase also. 



If the tube be filled with ether or alcohol, and placed in the 

 circuit, the powder will be inflamed. If it be filled with sulphuric 

 acid, which is a better conductor, the powder will be scattered 

 and not inflamed, but the dispersion will not be so great as when 

 metals only form the circuit. The same effect will be produced 

 by transmitting the charge through the animal economy, or 

 through water not inclosed in tubes, in which case the water 

 does not appear to oppose a sufficient resistance to the passage 

 of the fluid. 



But the most remarkable circumstance attending these phe- 

 nomena is, that it is immaterial whether the tube form part of the 

 circuit before the electrical fluid passes the gunpowder, or after- 

 wards. If the tube be placed on what I will call, for the sake of 

 distinction, the negative side of the powder, either in immediate 

 contact with the powder, the coating of the jar, or in any part 

 of an interval in 20 yards of chain, the powder will be invariably 

 inflamed when the charge is passed. 



In this experiment the effect appears to precede the cause ; 

 and it may be asked, does it not prove the existence of two 

 fluids ? Some would no doubt answer in the affirmative, but so 



