366 Conducting Rods. 



In 1*769, the Jacob tower, in Hamburg, was furnished with a 

 rod ; and after the cathedral at Sienna had been repeatedly struck 

 by lightning the authorities concluded to follow the example of 

 Hamburg, and erected conductors. The inhabitants at first re- 

 garded them with great terror, and stigmatized them as heretical* 

 But on the 10th of April, 1*7 1 7, a heavy shock of lightning visited 

 the tower and glided harmlessly to the earth ; the church has not 

 been injured since, and the conductors are absolved from the 

 charge of heresy. 



Old St. Paul's church in London, unprotected, by rods, was twice 

 struck and damaged. The present structure, though more elevated, 

 being provided with rods, has never suffered from electricity. 



The cathedral of Geneva, the most elevated in the city, for 

 more than two centuries enjoyed immunity from lightning; 

 while the neighboring bell tower of St. Gervais, though not so 

 elevated, has often been struck and damaged. In 1111, Saussurc 

 by examination discovered the cause to consist in a complete coat- 

 ing of tin plate from the top of the Cathedral spire to the base of 

 the tower, thence by metallic water pipes to the ground, forming 

 a series of conductors analagous to those of Harris. 



But if lightning rods are useful to protect buildings, still more 

 useful are they for the protection of ships. In the British navy, 

 between the years 1810 and 1815, forty sail of the line, twenty 

 frigates, and twelve sloops were damaged by lightning. Between 

 1*739 and 1*793, seventy-three men were killed, and several hun- 

 dred dangerously wounded by the same instrumentality. The 

 amount of property destroyed cannot be estimated. The main- 

 mast alone of a seventy-four, costs originally $5000. To this must 

 be added the cost of its removal, of ruined spars, rigging, hull and 

 stores, and the daily expenses of the ship, varying from $400 to 

 $550 per day. This estimate glances at the cost of repairing 

 those not totally destroyed by lightning. In the space of forty-six 

 years the average expense thus occurring amounted to $30,000 per 

 annum. Probably some of those ships that " sail from their port 

 and are never heard of more" are destroyed by lightning. 



To the foregoing estimate must be added the casualities occur- 

 ring to vessels weakened by the electric shock, and afterwards 

 lost in struggle with the wind or the foe. " The Guerriere is an 

 instance," says the Nautical Magazine, " of a frigate fighting a 

 superior force with her main mast in a defective state, by a stroke 

 of lightning, and which might have stood but for this defect. The 



