on the Wires of the 'Electric Telegraph. 189 



dundant electricity is given off at one place ; the velocity of 

 transmission of the wave as it passes the neighbouring body, 

 and its attraction for the wire, preventing a full discharge at 

 any one place. Tiie intensity of the successive explosions is 

 explained by referring to the fact, that the discharge from the 

 clouds does not generally consist of a single wave of electricity, 

 but of a number of discharges along the same path in rapid 

 succession, or of a continuous discharge which has an appre- 

 ciable duration ; and hence the wire of the telegraph is capable 

 of transmitting an immense quantity of the fluid thus distri- 

 buted over a great length of the conductor. 



The remarkable facts of the explosions of the electricity into 

 the air, and of the poles being struck in interrupted succession, 

 find a plausible explanation in another electrical principle 

 which I have established, namely, in all cases of the disturb- 

 ance of the equilibrium of the electrical plenum, which we 

 must suppose to exist throughout all terrestrial space, the state 

 of rest is attained by a series of diminishing oscillations. Thus 

 in the discharge of a Leyden jar, I have shown that the phae- 

 nomena exhibited cannot be explained by merely supposing 

 the transfer of a quantity of fluid from the inner to the outer 

 side of the jar ; but in addition to this we are obliged to admit 

 the existence of several waves, backwards and forwards, until 

 the equilibrium is attained. In the case of the discharge from 

 the cloud, a wave of the natural electricity of the metal is re- 

 pelled each way from the point on which the discharge falls, 

 to either end of the wire, is then reflected, and in its reverse 

 passage meets in succession the several waves which make up 

 the discharge from the cloud. These waves will therefore 

 interfere at certain points along the wire, producing, for a 

 moment, waves of double magnitude, and will thus enhance 

 the tendency of the fluid at these points to fly from the con- 

 ductor. I do not say that the effects observed were actually 

 produced in this way ; I merely wish to convey the idea that 

 known principles of electrical action might, under certain cir- 

 cumstances, lead us to anticipate such results. 



2. The state of the wire may be disturbed by the conduc- 

 tion of a current of electricity from one portion of space to 

 another, without the presence of a thunder-cloud ; and this 

 will happen in case of a long line, when the electrical condition 

 of the atmosphere which surrounds the wire at one place is 

 different from that at another. Now it is well known that a 

 mere difference in elevation is attended with a change in the 

 electrical state of the atmosphere. A conductor, elevated by 

 means of a kite, gives sparks of positive electricity in a perfectly 



