246 POPULAR SCIENCE MONTHLY. 



Experimental research now began to spread into Germany and 

 the Xetherlands. The electrical machine was greatly improved by 

 Professor Boze, of Wittenberg, and Professor Winkler, of Leipsic, 

 who respectively added the prime conductor and the silk rubber to 

 that important piece of apparatus. A Scotch Benedictine monk of 

 Erfurt — Professor Gordon — substituted a glass cylinder for the 

 sphere, and thereby brought the instrument in its essentials practi- 

 cally to the form in which it exists to-day. The improvement enabled 

 the production of very large sparks, which were caused to produce the 

 inflammation of various combustibles. Gordon went so far as to 

 ignite alcohol by means of a jet of electrified water. 



We now come to an epoch-making discovery — that of the con- 

 denser, or, in its conventional laboratory form, the Leyden jar. Pro- 

 fessor Muschenbroeck, of the University of Leyden, was struck with 

 the idea that it would be a good plan to try to prevent the dissipation 

 of the electric charge by inclosing the conductor containing it in an 

 insulating envelope. He therefore took a glass jar, partly filled it 

 with water, and electrified the latter. His assistant, who was holding 

 the bottle, accidentally touched the wire which made connection with 

 the water, and received on the instant a shock much more violent 

 than any that the electrical machine was capable of giving. This 

 led to the discovery that as the charge of vitreous electricity had 

 accumulated in the water, a corresponding charge of the opposite kind 

 had gathered upon the outside of the glass and been " bound " there, 

 as it is called, by the attraction exercised upon it by the charge on 

 the inside. It had been enabled to get upon the glass by the fact 

 of the assistant's hand having covered part of the surface of the 

 latter, and, since he stood upon the ground, the electricity had quietly 

 flowed from the latter up through his body to the outside surface of 

 the glass. 



The apparatus was quickly perfected by coating both the inside 

 and outside of a jar with tin foil, applying the charge by means of a 

 wire or chain to the inside coating and allowing the outer one to 

 stand upon the earth or upon a conducting substance in electrical 

 contact with the latter. The exaltation of spirit with which the 

 discovery was hailed by the savants appears to have been extraordi- 

 nary — one student who took a discharge through his body being 

 reported to state that he would not have missed the experience 

 for a fabulous consideration, and that he would not repeat it if it 

 were to save his life. In reality the advance was enormous; it 

 gave a means for literally bottling up electricity in quantities pre- 

 viously unthought of. The prime conductor of an electrical machine 

 could not retain any considerable quantity of electricity for the reason 

 that, a certain small intensity of electriflcation having been reached, 



