462 Dr. R. Hare's Ohjecliom to the Theories severally of 



fluid from the positive to the negative surface requisite for its 

 accomplishment, a current having a velocity exceeding two 

 hundred thousand miles in a second would be necessary. 



2. The only causes for the velocity of an electric current, 

 according to Franklin, are the repulsion between the particles 

 of the electric fluid of which it has been assumed to consist, 

 and the attraction between those particles and other matter. 

 These forces are alleged to concur in distributing the sup- 

 posed fluid throughout space, whether otherwise void, or 

 partially occupied by conducting solids or fluids. Hence, 

 when between two or more spaces, surfaces, or conducting 

 masses, there is an unequal distribution of the electric fluid, 

 the equilibrium is restored whenever a communication is 

 opened by means of a sufiiciently conducting medium. 

 Agreeably to this view of the subject, there seems to be n 

 resemblance between the supposed effort of the electrical fluid 

 to attain a state of equable diffusion, and that which would 

 exist in the case of a gas confined in adjoining receivers, so as 

 to be more dense within one than within the other; for, how- 

 ever the subtilty of the supposed electric fluid may exceed 

 that of any gas, there seems to be an analogy as respects the 

 processes of diffusion which must prevail. But on opening a 

 communication between cavities in which any aeriform fluid 

 exists in different degrees of condensation, the density must 

 lessen in one cavity and augment in the other, with a rapidity 

 which must diminish gradually, and become evanescent with 

 the difference of pressure by which it is induced. Far from 

 taking place in an analogous manner, electrical discharges are 

 effected with an extreme suddenness, the whole of the re- 

 dundancy being discharged at once, in a mode more like the 

 flight of a bullet projected with infinite velocity, than that of 

 a jet gradually varying in celerity from a maximum to a 

 minimum. 



3. So far, in fact, is an electrical discharge from displaying 

 the features which belong to the reaction of a condensed elastic 

 fluid, that, agreeably to the observations of our distinguished 

 countryman Henry, the result is more like the vibrations of 

 a spring, which, in striving to regain its normal position, goes 

 beyond it. The first discharge between the surfaces of a 

 Leyden jar is not productive of a perfect equilibrium. The 

 transfer of different polarities goes beyond the point of re- 

 ciprocal neutralization, producing a state, to a small extent, 

 the opposite of that at first existing; and hence a refluent 

 discharge ensues, opposite in direction to the primary one. 

 But even this does not produce an equilibrium, so that a 

 third effort is made. These alternate discharges were detected 



