VOL. LXVIII.] PHILOSOPHICAL TRANSACTIONS. 335 



buildings as were secure from attacks by lightning. The passage alluded to is 

 this: " buildings that have their roofs covered with lead or other metal, and 

 spouts of metal continued from the roof into the ground to carry off the water, 

 are never hurt by lightning; as, whenever it falls on such a building, it passes 

 in the metals, and not in the walls." Franklin's Exp. p. 48 1 . With this idea 

 the building at Purfleet, called the Board-house, was considered by that com- 

 mittee to be in a similar situation, and consequently secure from such attacks, 

 without having any other conductors than the leaden gutters, pipes, &c. As 

 the members of that committee then present seemed to be fully satisfied with 

 that determination, I proposed that the magazines themselves should be put into 

 the same circumstances; otherwise there would appear to be an inconsistency in 

 the different methods of securing those buildings. My argument had no other 

 effect than to occasion, at the next meeting of the committee, a resolution for 

 fixing pointed conductors to all the buildings. From this resolution I dissented, 

 and gave in writing my reasons at large for differing in opinion, which are 

 printed in your Transactions. 



What has been the consequence since the conductors were put up? Behold! 

 this very Board-house, which was never attacked before by lightning, hath very 

 lately been struck, and that within a few inches of the conductor; contrary to 

 Dr. Franklin's assertion, which positively says, that in such circumstances the 

 lightning passes in the metals, and not in the walls. We may refine in our rea- 

 soning on the philosophy of this event as much as we please; but let me tell 

 you, gentlemen, there is no getting rid of the fact: which, according to my 

 judgment, appears to be truly alarming. And, as I apprehend the reputation 

 of this learned society is greatly concerned therein, we ought immediately to 

 avail ourselves of this providential warning, and reject an apparatus which 

 threatens us every hour with some unhappy consequences. It is with very great 

 concern, that I am obliged to take notice, in this society, of a house, which is 

 of the first consequence in this kingdom, that hath pointed conductors also fixed 

 on it: I mean the King's, our most gracious patron and benefactor's. Who 

 were the advisers of them I know not; but as they are there, I thought it my 

 duty to mention them. 



In considering the propriety of pointed conductors, I think it necessary to 

 observe, that increasing the number of them in any given space does not by any 

 means, in my opinion, lessen the risk of accidents by lightning; but on the 

 contrary (at least in many cases) a greater number of such conductors will neces- 

 sarily invite a larger quantity of lightning. At Purfleet there are several of those 

 conductors; and by the storekeeper's letter sent to the Board of Ordnance, 

 which was lately read before us, it appears, that he himself observed a very 

 heavy cloud hanging over the house for some time before the stroke happened. 



