550 THE INTELLECTUAL RISE IN ELECTRICITY. 



(although the two extreme points were distant, in a straight 

 line, but 2800 feet) a water course nearly 8000 feet in 

 length. Here a wire, from the outer coating of a Leyden 

 jar, disposed in the window of a house overlooking the 

 river, was led over the meadows to the distant point, 

 where, as before, an observer held its end in one hand, 

 and established communication with the water with the 

 other. A second wire from the window went directly to 

 the river, so that it was necessary merely to bring the 

 house end of this wire to the ball of the jar to discharge 

 the latter. The experiment was successful but a new 

 question arose from it, because it had been noticed that 

 the u commotion " traveled over the circuit even when the 

 distant end of the wire did not communicate with the 

 water but with the land, touching the earth at a distance 

 of even twenty feet from the stream. Was the electrical 

 circuit formed throughout the windings of the river, or 

 by way of the much shorter path through the meadows? 

 Tests showed that the meadow-earth would conduct, and 

 this was supposed to be due to its damp condition. At all 

 events, thought Watson, the matter must be tested. So 

 observers, at the ends of a wire about 500 feet long, were 

 insulated on pitch cakes and told to touch the ground 

 with their iron rods. The shocks from ajar in the circuit 

 were felt smartly by both. That, and similar trials, settled 

 the matter of the feasibility of making the earth a part 

 of the circuit, and made further experiments on long 

 water-courses needless. 



Watson had noticed that when the wire running across 

 Westminster Bridge touched wet stones the shock trans- 

 mitted seemed to lose strength, and that the same result 

 happened when it lay on wet grass. He surmised at once 

 that a leakage of the charge thus took place from the 

 wire. He now provided a circuit nearly four miles in 

 length, being two miles of wire supported on dry sticks 

 and two miles of earth. The observers at the distant 

 stations fired muskets to notify the man at the jar when 



