PROGRESS IN ELECTRICITY 



bits of paper, leaf-brass, and other light substances, 

 and that this phenomenon was supposed to be elec- 

 trical. This led him finally to determine the hitherto 

 unsuspected fact, that the glow in the barometer was 

 electrical as was also the glow seen in his whirling 

 globe. Continuing his investigations, he soon discov- 

 ered that solid glass rods when rubbed produced the 

 same effects as the tube. By mere chance, happening 

 to hold a rubbed tube to his cheek, he felt the effect of 

 electricity upon the skin like " a number of fine, limber 

 hairs," and this suggested to him that, since the mys- 

 terious manifestation was so plain, it could be made to 

 show its effects upon various substances. Suspending 

 some woollen threads over the whirling glass cylinder, 

 he found that as soon as he touched the glass with his 

 hands the threads, which were waved about by the 

 wind of the revolution, suddenly straightened them- 

 selves in a peculiar manner, and stood in a radical po- 

 sition, pointing to the axis of the cylinder. 



Encouraged by these successes, he continued his ex- 

 periments with breathless expectancy, and soon made 

 another important discovery, that of " induction," al- 

 though the real significance of this discovery was not 

 appreciated by him or, for that matter, by any one 

 else for several generations following. This discovery 

 was made by placing two revolving cylinders within an 

 inch of each other, one with the air exhausted and the 

 other unexhausted. Placing his hand on the unex- 

 hausted tube caused the light to appear not only upon 

 it, but on the other tube as well. A little later he 

 discovered that it is not necessary to whirl the 

 exhausted tube to produce this effect, but simply 



VOL. II. 18 26l 



