248 POPULAR SCIENCE MONTHLY. 



existence of two fluids. He was led to this belief by observing tliat 

 he obtained a larger spark between two oppositely electrified bodies 

 than from either to the earth. 



From this time on there appears upon the scene a host of work- 

 ers in this field, one of the most prominent being the distinguished 

 American, Benjamin Franklin. Somewhat previous to his remark- 

 able work, or about 1750, Boze made certain discoveries in the matter 

 of the surface tension of conducting liquids being diminished by elec- 

 trification, and Mowbray and Nollet ascertained that the vegetation 

 of flowers and of vegetating seeds was hastened by electrifying them. 



Franklin (born 1706, died 1790) made the important discovery of 

 the active discharge of electricity from an electrified body by points 

 as well as the converse of it — i. e., that electricity was rapidly ab- 

 stracted from a charged atmosphere by points. This enabled him to 

 increase the efiiciency of the electrical machine by adding a comb- 

 shaped series of points to the collector of the prime conductor. 



Up to this time, although the identity of lightning with electri- 

 city had long been suspected, it had not been at all established, and 

 to Franklin may be said to belong the honor of doing so, although 

 in this, as in the case of the invention of the Ley den jar, there appears 

 to have been successful contemporaneous research elsewhere. Be- 

 fore performing his great experiment Franklin published a book 

 strongly supporting the belief in the identity of the two. Once 

 liaving conceived the idea of drawing electricity from the upper 

 atmosphere, he unfortunately lost some time through waiting for the 

 completion of the spire of a certain church in Philadelphia, from 

 the top of which he hoped to be able to collect electricity by means 

 of a wire, but finally hit upon the device which now fills much the 

 same place in connection with his memory that the classical cherry 

 tree does with Washington's — the lightning-collecting kite. This 

 apparatus was very simply constructed, and had a pointed wire pro- 

 jecting a short distance above the framework. It was controlled, 

 and electrical connection made, by an ordinary string which termi- 

 nated in a short length of silk ribbon to protect the person from pos- 

 sible injury, and to give electricity a chance to accumulate in the 

 system, by insulating the " line." At the end of the string proper 

 Franklin fastened a metallic key. In company with his son he flew 

 the kite during a thunderstorm which occurred in June, 1752; for 

 some time no electric disturbance approached the neighborhood, and 

 he was on the point of abandoning the experiment when he obser^'cd 

 what he had been waiting for — the outer fibers of the string stand- 

 ing out from the latter by repulsive force — and, ap])lying his knuckle 

 to the key, he drew a spark. Subsequently, when the rain soaked the 

 string and caused it to conduct much better, there was a fine supply 



