540 9f TOM I'BOTBCTION OF BUILDINGS FROM LIGHTNING. 



ptutujtiuii for an ordinary building against any thunderstorm in this climate. 

 The copper wire may be built into the wall to prevent theft, but should be 

 ^mmH^j^ to any outside metal such as lead or zinc on the roof, and to metal 

 nun-water pipes. In the case of a powder-mill it might be advisable to make 

 (he network closer by carrying one or two additional wires over the roof and 

 down the walla to the wire at the foundation. If there are water or gas- 

 I.IJKW which enter the building from without, these must be connected with 

 the system of conducting-wires, but if there are no such metallic connections 

 with distant points, it is not necessary to take any pains to facilitate the 

 escape of the electricity into the earth. 



Still less is it advisable to erect a tall conductor with a sharp point in 

 order to relieve the thunder-clouds of their charge. 



It is hardly necessary to add, that it is not advisable, during a thunder- 

 storm, to stand on the roof of a house so protected, or to stand on the ground 

 outside and lean against the wall. 



