68o THE POPULAR SCIENCE MONTHLY. 



garden. The rod was finished at the top by a sharp point of bronzed 

 steel, and it terminated at the bottom, five feet above the ground, in 

 a smaller horizontal rod, which ran to a table in a kind of sentry-box, 

 furnished with electrical apparatus. On May 10th, when M. Dalibard 

 was himself absent in Paris, the apparatus having been left tempo- 

 rarily in the charge of an old dragoon named Coiffier, a violent storm 

 drifted over the place, and the old dragoon, who was duly instructed 

 for the emergency, went into the sentry-box and presented a metal 

 key, partly covered with silk, to the termination of the rod, and saw a 

 stream of fire burst forth between the rod and the key. The old man 

 sent for the Prior of Marly, who dwelt close by, to witness and con- 

 firm his observation, and then started on horseback to Paris, to carry 

 to his master the news of what had occurred. Three days afterward, 

 that is, on May 13, 1752, M. Dalibard communicated his own account 

 of the incident to a meeting of the Academic des Sciences, and an- 

 nounced that Franklin's views of the identity of the fire of the storm- 

 cloud with that of the electrical spark had been thus definitely estab- 

 lished. 



Before the success of M. Dalibard's experiment could be reported 

 in America, however, Franklin had secured his own proof of the iden- 

 tity by the memorable experiment with the kite, so well known to the 

 scientific world. He was anxiously waiting for the erection of the first 

 steeple in Philadelphia for the opportunity which this would afford 

 him for the support of a lofty iron rod, when the happy idea occurred 

 to him to try, in the mean time, upon some suitable occasion, whether 

 he could not contrive to hold uj) a lightning-conductor toward a storm- 

 cloud by means of a kite. On the evening of July 4th, that is, fifty-two 

 days after the experiment of M. Dalibard, his kite was raised during a 

 thunder-storm, and, with the help of his son, he drew electric sparks 

 from the rain-saturated string, as the two stood in the shelter of an 

 old cow-shed in the outskirts of Philadelphia. He held the kite by a 

 silken cord that was attached to a key at the bottom of the string, and 

 with this arrangement he charged and discharged an ordinary Leyden- 

 jar several times in succession. Franklin at first not unnaturally con- 

 ceived that he had actually drawn the lightning down from the storm- 

 cloud. He was, however, no doubt mistaken in this. The storm-cloud 

 had inductively excited the neighboring surface of the earth, and what 

 Franklin saw was the electric stream escaping out through the wet 

 string toward the storm-cloud to relieve the tension set up by this in- 

 duction. It was in the summer of the same year, after the perform- 

 ance of this world-renowned experiment with the kite, that Franklin 

 attached to his house a lightning-conductor, which was composed of 

 an iron rod, having a sharp steel point projecting seven or eight feet 

 above the roof, and with its lower end plunged about five feet into the 

 ground. 



As a matter of course, the new doctrine of Franklin and his allies 



