324 HISTORY OF SCIENCE. 



On the death of Stephen Gray, in 1736, a series of researches in elec- 

 tricity was entered upon by a very active member of the Royal Society, 

 Dr. J.T. DESAGULIERS (1683 1744), who exhibited many experiments 

 to illustrate the fresh facts he continued to discover. And, indeed, new 

 observations of electrical phenomena accumulated very rapidly in all 

 quarters, for the singular nature of these phenomena excited great 

 interest in learned and simple alike. But there were not wanting 

 severely practical men who regarded all the interest which electricity 

 was exciting as so much idle curiosity and childish amusement, and 

 these persons raised the cry of cui lono ? It is modestly, piously, and 

 philosophically replied to by Watson, who admitted that the electri- 

 cians of his day had not advanced far enough in their discoveries to 

 make them useful to mankind, but observed that in every department 

 of physical science perfection is attained only by very slow degrees. 

 " It is our duty to continually advance in our knowledge, and to leave 

 the rest to that Providence who has created nothing in vain." 



Towards the middle of the eighteenth century another electrical 

 phenomenon was discovered, and, familiar as it is now, it is difficult to 

 picture the sensation it produced. It was an experiment which caused 

 a new word to be added to every language in Europe ; or, rather, it 

 was the occasion of a term, originally purely scientific, being adopted 

 into the common language, of course with a derived signification, as 

 when it is said that a speech "electrified the audience," etc. The dis- 

 covery to which we here allude was that of the Leyden Jar. It was 

 made by MUSSCHENBROECK (1692 1761), at Leyden, in 1746. He 

 was trying to find a means of preserving electricity, when it occurred 

 to him that if the water in a glass bottle were electrified, and the bottle 

 closed by a stopper, the electricity might remain in the water for an 

 indefinite time, inasmuch as it would be surrounded by a non-con- 

 ducting substance. It was while endeavouring to realize this idea 

 that Musschenbroeck became the first man to experience the electric 

 shock. There is every reason to believe that the shock in question was 

 very much weaker than those that are now taken for amusement even 

 by children. But the novelty of the sensation made the first experi- 

 menters unconsciously exaggerate to themselves the impressions they 

 received. Let us see how Musschenbroeck himself describes his own 

 sensations in the letter in which he, on the 2oth of April, 1746, 

 announces his discovery to Reaumer : 



" I wish to describe to you a new but dangerous experiment, which 

 I advise you not to attempt yourself. I was engaged in some researches 

 on the power of electricity, and for that purpose I had suspended (see 

 engraving), by two blue silk lines, a gun-barrel, which received the elec- 

 tricity of a glass globe rapidly turned on its axis, and rubbed by ap- 

 plying the hands to it. At the end of the gun-barrel, away from the 

 globe, there hung a brass wire, the end of which plunged into a round 

 glass bottle, partly filled with water. I was holding the bottle with 



