THE SMALLEST WORKERS 



ously or slide along the carpet, you may light a gas jet 

 with the spark which will spring from your finger to 

 the tip of the jet, provided the latter is of metal or other 

 conducting substance; and even if you attempt to 

 avoid the friction between your feet and the carpet as 

 much as possible, you may be constantly annoyed by 

 receiving a shock whenever you touch any conductor, 

 since, in spite of your efforts, the necessary amount of 

 friction sufficed to generate a store of statical electricity. 



An illustration of the development of this same form 

 of electricity, on a large scale, is supplied by the fa- 

 miliar statical machine, which consists of a large circle of 

 glass, so adjusted that it may be revolved rapidly against 

 a suitable friction producer. With such a machine a 

 powerful statical current is produced, capable of gen- 

 erating a spark that may be many inches or even several 

 feet in length, a veritable flash of lightning. It is 

 with such a supply of electricity conducted through a 

 vacuum tube that the cathode ray and the Roentgen 

 ray are produced. 



Such effects as this suggest considerable capacity for 

 doing work. Yet in reality, notwithstanding the very 

 sporadical character of the result, the quantity of 

 electricity involved in such a statical current may be 

 very slight indeed. Even a lightning flash is held to 

 represent a comparatively small amount of electricity. 

 Faraday calculated that the amount of electricity that 

 could be generated from a single drop of water, through 

 chemical manipulation, would suffice to supply the 

 lightning for a fair-sized thunder-storm. Nevertheless 

 the destructive work that may be done by a flash of 



VOL. VI. II [ l6l ] 



