ELECTRICITY. 



415 



History. 



Experi- 



l.abours of 

 Dr Dem. 

 gulien. 



Died 174-1. 



exert their electricity simply by exposure to the open History, 

 air. Dr Desaguliers was the first who ranked pure air -Y"""' 

 among electrics ; and hence 1 e endeavours to account 

 for the rise of vapours on electrical principles. In 

 1712 he published an excellent dissertation on electri- 

 city, containing a complete account of all that had been 

 done upon that subject ; and he had the honour of re- 

 ceiving, for this work, the prize medal of the Academy 

 of Bourdeaux. Dr Desaguliers was the first who dis- 

 tinguished bodies into electrics and conductors ; and he 

 gave a list of substances which belong to these two 

 classes. 



About this time the subject of electricity began to Labours, of 

 be assiduou-ly cultivated by the Germans. Professor *^ er " 

 Boze of Wittemberg revived the use of the globe of 

 glass, and added a prime ci.nduc'or, which consisted of 

 an iron or tin tube, at first supported by a man stand- 

 ing upon cakes of rosin, and afterwards by silk strings. 

 Prot'<j.-M>r Winkler invented the cushion for exciting the 

 globe; and Mr Gon'nn. a Scotch Benedictine monk, 

 and professor of philosophy at Erfurth, had the merit of 

 iirst intro'iucing the cylinder of glass. The apparatus 

 : t;\ AV. s- much more various and powerful 

 than wh.it had been employed either in France or Eng- 

 land ; r.rid hence the foreign electricians were led to se- 

 veral interesting results. In 1744, Dr Ludolf, of Berlin, A.D. 17*4. 

 set fire to the ethereal spirits of Frobenius, by the sparks 

 from a glass tube, and also by those from an iron conduc- 

 tor. Professor Winkler j>erfonned the same thing by a 

 spark from his finger, and also kindled French brandy, 

 corn spirits, and other sill weaker spirits, after they were 

 previously heated. Oil, pitch, and sealing-wax, when 

 heated to a very great degree, were also kindled by the 

 electric spark. 



A number of amusing experiments were about this 

 time introduced by the Germans Mr \Vinkler con- 

 structed a wheel which moved by means of electricity. 

 Mr Boze conveyed electricity from one man to another, 

 18 feet distant, by a jet of water ; and Mr Gordon al- 

 so kindled spirits by a jet of electrified water. Dr 

 Miles, in 17!. 5, succeeded in kindling phosphorus by 

 the electric spark. 



Our countryman, 'Dr Watson, afterwards Sir Wil- Labours of 

 Ham Watson, now began his successful career as an Dr Wa 

 electrical discoverer. His attention seems to have been A ' "' 

 directed to this subject by the discoveries of the Ger- 

 mans, which he carefully repeated. lie fired inflam- 

 mable air by the electric spark ; and, by means of a 

 drop of cold water, and even with ice, lie kindled both 

 spirits of wine and inflammable air. He also succeed- 

 ed in firing gun-powder, and in discharging a musket 

 by electricity, when the gun-powder had been prepa- 

 red by the admixture of a little camphor. In the ex- 

 periments of the Germans, the substances which were 

 set on fire were always held by some person who was 

 nut electrified ; but Dr Watson performed all the ex- 

 periments by what he has called the iv/W.v/r<; norvcr of 

 electricity, the fluid being held by an electrified person, 

 and then touched by the finger of a person not electri- 

 fied. He observed, that electricity experienced no de- 

 viation from its rectilineal direction, in passing through 

 glass. The electricity transmitted through the glass, 

 was always strongest when the glass was warm. He 

 showed that the fire of electricity was neither affected 

 by the presence nor absence of other fire ; that the 

 smoke of original electrics was a conductor of electri- 

 city ; and that the flame of a candle was a perfect con- 

 ductor. The attention of Dr Watson was next occu- 

 pied by^the subject of the Leyden phial, which was at 



