234 GENERAL CONDITIONS OF SCIENTIFIC RESEARCH. 



of an unexpected character : Von Kleist, a German pre- 

 late of Camin in Pomemnia, during the year 1745, and 

 Cunaeus of Leyden, in 1746, appear to be the first who 

 observed the property of the Leyden phial. The latter, 

 whilst handling a vessel of water connected with an electric 

 machine, received a sudden shock in his arms and breast 

 by bringing the inside and outside of the jar into con- 

 nection through his body. This circumstance, on being 

 published, excited much surprise, and Muschenbroeck/ 

 after receiving one shock, said he would not receive 

 another for the entire kingdom of France. The wonder- 

 ful experiment was repeated in various forms all over 

 Europe. The Abbe Nollet, in the presence of the king of 

 France, sent a shock through a circle of 180 soldiers, also 

 through a line of men and wire of 900 toises in length, 

 and Dr. Watson, of Shooter's Hill, in England, sent it 

 through a length of 12,000 feet of wire. 



' The variation in the length of the pendulum beating 

 seconds at different places, was first discovered by Richter 

 in the year 1672, whilst observing transits of the fixed 

 stars across the meridian at Cayenne. He found that his 

 clock lost 2 minutes 8 seconds daily, which induced him 

 to determine the length of a pendulum beating seconds in 

 that latitude ; and repeating the experiments on his 

 return to Europe, he found the seconds pendulum at 

 Paris to be more than one-twelfth of an inch longer than 

 at Cayenne.' 1 



Different discoveries occur with very different degrees 

 of unexpectedness ; great ones rarely come unawares. The 

 quantitative relations of known scientific truths are also 

 rarely found by accident, because definite researches are 

 specially made to find them. The discovery of new quali- 



1 Mrs. Somerville, Connection of the Physical Sciences, 2nd edit. p. 66. 



