'igO PHILOSOPHICAL TRANSACTIONS. [anNO 175'2. 



of thunder and electricity, they prepared themselves for making the expe- 

 riments. * 



M. d'Alibard chose, for this purpose, a garden situated at Marly, where he 

 placed on an electrical body a pointed bar of iron, of 40 feet high. On the 10th 

 of May, 20 minutes past 2, afternoon, a stormy cloud having passed over the 

 place where the bar stood, those that were appointed to observe it, drew near, 

 and attracted from it sparks of fire, perceiving the same kind of commotions as 

 in the common electrical experiments. M. de Lor, sensible of the good success 

 of this experiment, resolved to repeat it at his house in the Estrapade at Paris. 

 He raised a bar of iron QQ feet high, placed on a cake of resin, 2 feet square, 

 and 3 inches thick. On the 18th of May, between 4 and 5 in the afternoon, a 

 stormy cloud having passed over the bar, where it remained half an hour, he 

 drew sparks from the bar. These sparks were like those of a gun, when, in the 

 electrical experiments, the globe is only rubbed by the cushion, and they pro- 

 duced the same noise, the same fire, and the same crackling. They drew the 

 strongest sparks at the distance of g lines, while the rain, mingled with a little 

 hail, fell from the cloud, without either thunder or lightning ; this cloud being, 

 according to all appearance, only the consequence of a storm, which happened 

 elsewhere. From this experiment they conjectured, that a bar of iron, placed 

 in a high situation on an electrical body, might attract the storm, and deprive the 

 cloud of all its thunder. 



I do not know. Sir, whether Mr. Franklin's letters were before your conside- 

 ration on earthquakes : if they were, we are obliged to Mr. Collinson for his 

 communication of Mr. Franklin's notions ; if they are not, you deserve the 

 honour of the discovery ; and whoever it be, it is still to the r. s. we owe the 

 communication of this ingenious thought, which the experiments ofM. d'Alibard 

 and M. de Lor have confirmed. These 2 learned men deserve that esteem of our 

 nation which their talents have a long time procured them. 



Letter 2. Dated St. Germain, June 14, 1752. — M. le Monnier, having 

 prepared to repeat the same experiments, avoided that inconvenience in the resin 

 cakes being wetted by the rain. He placed, in the garden of the hotel de 

 Noailles, a wooden pole, of about 30 feet high, at the end of which was fixed a 

 large glass tube, which received at the other end a long tin pipe ; and this pipe 

 received again, in its turn, a pointed bar of iron, of about 6 feet high. The 

 glass tube was instead of the cake of resin, to hinder the communication of the 

 electricity from the tin pipe to the pole. A wire was carried from the bar of 

 iron, which rested on a silken cord, about 50 paces from the pole ; but rain 

 coming on, the wire was conducted into the house. We perceived the commo- 

 tions of the electrical matter from the first clap of thunder ; it produced sparks, 

 and there were certain intervals, when the commotions were so strong, that they 



