205 



bered that one hundred and fifty years ago not only was there 

 no telegraph, but the magnetic, chemical and motor powers of 

 electricity were not even dreamt of. It was fifty years before 

 Galvani published his account of the convulsions produced in a 

 frog's leg by the contact of dissimilar metals. Volta was just 

 five years old. To what is now an open book full of wonders 

 which every school-boy can read without obscurity or hesita- 

 tion, naught but the preface had appeared. That preface dates 

 from three centuries before Christ, when Thales of Miletus 

 drew attention to the curious property of attraction developed 

 on rubbing amber. The Greeks explained this by the theory 

 that friction evoked the animating soul of the amber which 

 seized upon light particles near it. For nearly two thousand 

 years there was no substantial addition to knowledge until 

 Gilbert discovered that glass, sealing wax, sulphur, and other 

 substances could also be electrified. Then fifty years elapsed 

 before a rude machine was made from which vivid sparks 

 could be drawn. After another fifty years the resemblance 

 between these zigzag sparks and the lightning flash was com- 

 mented on. The first chapter was fairly opened when the 

 discovery of the Leyden jar enabled the experimenter to im- 

 prison the fiery spirit and perform many remarkable tricks 

 with it. At this time Franklin had reached middle life a' id 

 retired from business with an independent fortune. He gave 

 his scientific enthusiasm a free rein with the Leyden jar and 

 the frictional machine. With the aid of his Philadelphia col- 

 laborators many ingenious experiments were devised. Their 

 joint study proved so fruitful that in the course of six years 

 they advanced the science of frictional electricity more than 

 the rest of the world had done in two thousand. 



It was this chapter which, according to Goethe, had been 

 handled better than any other in modern times. For illustra- 



