140 PHILOSOPHICAL TRANSACTIONS. [aNNO I764. 



or single rod, there may be, in some parts of its length, in any place convenient 

 for observation, a space left where the metal is discontinued ; but this space 

 should not exceed '2 inches. The two extremities of the metal at this interrup- 

 tion should be furnished with brass knobs not less than an inch in diameter. 

 By this method, though the effects of the apparatus would not be considerably 

 lessened, they might be observed. For at times when no lightning was visible, 

 but when clouds replete with it came near the apparatus, or rain from them fell 

 upon it, there would be a snapping from one of the brass knobs to the other. 

 When indeed the lightning was near, there would not only be this snapping, 

 but, if the cause was great, a stream of fire would be seen, as in M. Romas's 

 kite,* to pass from one of these to the other, as the best and nearest conductor. 

 If danger however is apprehended, a piece of chain may be always at hand to be 

 hung occasionally on the upper knob, so as readily to fall in contact with the 

 lower. Otherwise, if while the metallic communication is divided, though 

 when entire it is apprehended it may be touched with safety, a person should 

 touch the rod above the division, and at the same time touch or come very near 

 the rod below the division with any part of his body ; and at the same instant if 

 a smart stroke of lightning affected the apparatus, he would certainly be 

 destroyed, as happened to professor Richmann at Petersburgh ; the lightning 

 going through his body from one part of the apparatus to the other, which it is 

 believed it will not do while the metallic communication is compleat. 



8. I have not heard that there has been here of late any particular mode of 

 buildings, adapted to powder magazines, to diminish the shock of the explosion 

 in case of accident ; nor do I believe that any attention has been here given, in 

 constructing these buildings, to prevent, by an apparatus of this kind, the effects 

 of lightning. 



XLI. An Account of the Effects of Lightning on St. Bride's Church, Fleet 

 street, on the I8th of June, 1764. By Edward Delaval, Esq, F. R. S. 

 p. 227. 



The construction of this spire is somewhat similar to that of an apparatus 

 purposely contrived to draw the lightning from the clouds, as it runs up towards 

 a point, and ends in a metal vane and cross, the figure of which, as well as the 

 materials they consist of, seem calculated to admit the lightning with the least 

 resistance. The first marks of it are seen at the top of the copper cross, which 

 is the highest part of the building, the gilding is by the explosion partly torn off 

 and partly discoloured, so as to differ remarkably from the rest of the cross 

 where the gilding is very well preserved. Some small pieces of solder are 



* PJiil, Trans, abridged, vol. xi. p. 380. 



