Art. XI. — On Lightning Conductors generally, tvith special 

 reference to the Conductor attached to the tower and spire 

 of the Wesley Church, Melbourne. By Sizar Elliott, Esq. 



[Read before the Institute, 3rd August, 1859.] 



Mr. President and Gentlemen, — 



My attention to this subject (Lightning Conductors) arose 

 from two causes. First, on the completion of the spire of 

 the "Wesley Church by the architect, Joseph Reed, Esq., a 

 heavy thunderstorm passed over Melbourne, and feeling an 

 interest in the building as an architectural embellishment to 

 the city, I was led to look into the subject of its protection 

 from lightning; and, secondly, from lately reading in one 

 of the daily papers that the minister of a church in Castle- 

 maine had contracted to have an iron rod erected as a pro- 

 tection from the electric fluid at a cost of five pounds. This 

 arrangement, i.e., an iron rod, appearing so deficient in the 

 present advanced state of science, I considered it my 

 duty to introduce the subject to your notice, so that a greater 

 amount of information might be diffused among the public. 

 I have, therefore, endeavored to make this paper as practical 

 as possible, so that for the future our public buildings might 

 be better protected than they are at present. 



My authorities are Sir Snow Harris, Sir David Brewster, 

 and others, all names well known to science. 



The distinction between perfect and imperfect conductors 

 rests in the time they require to convey the electric fluid to 

 the earth. From experiments made, it appears that copper 

 transmits the fluid in a thousandth part of the time that 

 water does, and several thousand times quicker than dry 

 stone. Iron, which is generally used, conducts the fluid 

 twenty times slower than copper; and as the conductor, 

 when in action, is thrown into vehement repulsion, it is ne- 

 cessary that there should be a considerable amount of strength 

 employed to prevent disruption, and a considerable area, as 

 the fluid travels only on the surface. 



The rapidity of the transit, as estimated by Helvig, of 

 Germany, is probably from eight to ten miles in a second. 



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