On Lightning Conductors. 115 



from the bottom of the rod to the nearest gas or water 

 main, not merely to a lead pipe, and be soldered to it ; or a 

 tape may be soldered to a sheet of copper 8 feet x 3 feet^ 

 and rV iiich thick, buried in permanently wet earth, and 

 surrounded by cinders or coke ; or many yards of the tape 

 may be laid in a trench filled with coke, taking care that the 

 surfaces of copper are, as in the previous cases, not less thar 

 18 square feet. Where iron is used for the rod a galvanised 

 iron plate of similar dimensions should be employed. 



14. Inspection. — Before giving his final certificate, the 

 architect should have the conductor satisfactorily examined 

 and tested by a qualified person, as injury to it often occurs 

 up to the latest period of the works from accidental causes, 

 and often from the carelessness of workmen. 



15. Collieries. — Undoubted evidence exists of the ex- 

 plosion of firedamp in collieries, through sparks from 

 atmospheric electricity being led into the mine by the wire 

 ropes of the shaft and the iron rails of the galleries. Hence 

 the headgear of all shafts should be protected by proper 

 lightning-conductors. 



(Signed) 



W. Grylls Adams, 

 W. E. Ayrton. 

 Latimer Clark. 

 E. E. Dymond. 



C. Carey Foster. 



D. E. Hughes. 



T. Hayter Lewis. 

 W. H. Preece. 

 G. J. Symons. 

 John Whichcord. 



A careful inspection of lightning conductors upon 

 numerous public and private buildings in Melbourne reveals 

 endless departures from the preceding rules, and leads to the 

 conclusion that, as generally applied here, conductors are 

 rarely as efficient as they might and ought to be, while in 

 not a few cases they are so bad as to be a positive source of 

 danger. The principal faults that have come under my 

 notice are : — 



1st. Blunt points. These impair the action of the con- 

 ductor in silently discharging the atmospheric electricity. 



i2 



