STvi PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. 



electrizable bodies, thus disposed in open air, were sometimes electrized under 

 thick clouds, but without thunder, lightning, or even without rain or hail. 



The Abbe Nollet recommends, that these experiments should be made with 

 circumspection, as he has been informed by letters from Florence and Bologna, 

 that those who have made them there, have had their curiosity more than satis- 

 fied by the violent shocks, which they have sustained, in drawing off the sparks 

 from an iron bar electrized by thunder. One of these in particular says, that 

 once, as he was endeavouring to fasten a small chain, with a copper ball at one 

 of its extremities, to a great chain, which communicated with the bar at the 

 top of the building, in order to draw off the electrical sparks by means of the 

 oscillations of this ball, there came a flash of lightning, which he did not see, 

 but which affected the chain with a noise like wild-fire. At that instant, the 

 electricity communicated itself to the chain of the copper- ball, and gave the ob- 

 server so violent a commotion, that the ball fell out of his hands, and he Was 

 struck backwards 4 or 5 paces. He never had been so much shocked by the 

 Leyden experiment. 



From the experiment at Marly-la-ville, and those which have been made since, 

 have been drawn 2 consequences : one, that the matter of thunder, and that of 

 electricity, are one and the same : the other, that by the means of pointed iron 

 rods, one might, without its doing any harm, draw off all the fulminating matter 

 from a stormy cloud. But our author has shown, that pointed bodies are not 

 absolutely necessary ; and is desirous we should not too hastily believe, that 

 mischiefs arising from thunder may be averted by the apparatus proposed. He 

 thinks the means vastly too small for the magnitude of the cause. This first 

 letter to Mr. Franklin is an introduction to the 5 subsequent ones. 



The 2d letter treats of the nature of the electric matter. In this its analogy 

 with fire is considered and proved ; and the author takes notice that Mr. Franklin, 

 he imagines, who has certainly made some important discoveries in the pro- 

 perties of electricity, cannot but be dissatisfied with the editors of his woric, for 

 publishing, "' that he exhibited to our consideration an invisible subtil matter, 

 disseminated throughout all nature, &c. which had hitherto escaped our obser- 

 vations." The latter part of which assertion is not strictly true ; as the consi- 

 dering the matter of fire, and that of electricity, to be one and the same, is a 

 fundamental principle of what both the Abbe Nollet and Mr. W. formerly pub- 

 lished on this subject. 



The 3d letter to Mr. Franklin contains several proofs, that glass is not im- 

 permeable to the electric matter. Some of which experiments on this subject 

 Mr. W. heretofore laid before the r. s. and they are in his opinion fully 

 conclusive. 



The 4th letter to Mr. Franklin relates to several phenomena of tlie Leyden 



