418 



E L E C T R I C IT Y. 



ful electrical machine. He cndoivoured to shew that 

 ~~~ """*' itootogeneous bodies receive electricity fn proportion to 

 their surface, and that a small stripe of lead, with a given 

 arc*, received more electricity than a square sheet of 

 the same superficial contents. Dr Watson, however, 

 afterwards found that these results were incorrect. 

 Prior to the great experiments made in l-'.ngland. l.e 

 Moiinicr likewise mnde a number of expel intents on 

 the passage of electricity through water and along wire, 

 but he was unable to determine the rate of its motion. 

 lie was also the first, according to Buffon, wlio di-co- 

 yered that the Lcyden phial would retain its electricity 

 for a long time alter it was charged. In a I'm-: 

 son it once retained its charge for :5fi hours. Mr Sinea- 

 ton remarked, tiiat if any person, insulated, pressed 

 wit'i tie flat part of his hand against the globe or cy- 

 linder, while another person, not insulated, excited the 

 globe witli his hand, the insulated person would scarcely 

 < ' dricity, but would be electrified very 

 powerfully when he merely laid his fingers lightly 

 on the globe. Mr Sine-ten also found, that the red 

 hot part of an iron bar could be electrified as sti 

 as the. cold psrts on each side of it. Dr Miles perform - 

 i-i.'-.cnt- in electricity, without having 

 made any great discovery. He succeeded in kindling 

 common lamp spirits, by exciting a stick of common 

 black sealing wax with paper or dry flannel, and he 

 perceived that a globular spot of fire appeared first on 

 his finger when presented to the excited wax, and that 

 from this spot there issued regular streams towards the 

 wax, like the tail of a comet. The same author procu- 

 red a tube of green glass, which he could never excite 

 without great trouble. 



i .:A, -.-.ir .. ; The subject of electricity was cultivated by the Abbe. 

 IT ttfollet with great assiduity and success. He was the friend 

 iJ ' i 1 1770.' "^ os'ociate of Dufay, and was worthy of succeeding 

 him in his careerof discovery. He observed thattheelec- 

 tricity of a body placed in the atmosphere of an electri- 

 fied body, was of the same kind with that of the electrified 

 body, a result, however, which was found to be incorrect ; 

 that jiointcd bodies threw out brushes of electric light, 

 but didnot display other signs of electricity so powerfully 

 as blunt bodies; that the smoke of gum lac, turpentine, 

 karabc, and sulphur, were not so good conductors of elec- 

 tricity as the smoke of linen, wood, the vapour of writer, 

 and the effluvia of burning tallow and other fat substan- 

 ces ; thata picceofredhot iron throwing off ignited sparks, 

 and placed atthedistance of 6inches from an excited tube, 

 deprived it in two or three seconds of all its electricity, 

 but refused to affect the tube at the same distance be- 

 fore it ceased to be red ; that an excited tube lost none 

 of its electricity in the focus of a burning mirror; that 

 glass and other electrics were more strongly excited in 

 the open air than in vacua ; that the electric light in 

 vacua was more diffuse and unbroken than in the open 

 air; and that oil of turpentine, upon a piece of woalUa 

 doth, was capable of exciting glass very powerfully, 

 but lost this quality by the least intermixture of water. 

 The Abbe Nollet was the first person who made any 

 accurate experiments on animal and organised bodies. 

 This serie^ of experiments he began with several on eva- 

 poration, &c. He ascertained that electricity augments 

 ;tural evaporation of fluids, and that those eva- 

 porate most in this way that are most evaponiblc in 

 ordinary cases ; that electricity has the greatest effect 

 in evaporating fluids, when they are contained in \ es- 

 seli that arc non-electric, and that it docs not make 

 thuds evaporate through the pores either of metal or 

 glass. Mr Boze having informed the Abbe Nollet 



that capillary tubes which din-barged water only by 

 drops, afforded Constant -trc.uu when elcctri'icd, he 

 made numerous experiments on that .subject, lie 

 found thnt the stream of water was neither sensibly ac- 

 celerated nor retarded when the bore was alx>vc a line 

 in diameter. When it was a line in diameter, the fluid 

 experienced a small acceleration, and when it was ca- 

 pillary, the electrified jet not only became a continued 

 -in am, and divided into several .streams, but was also 

 considerably accelerated, and this in proportion to the 

 surliness ol the bore. The stream of electrified fluid 

 txhibittd in thrse experiments had a verv brilliant 

 effect when they were performed in the dark. The 

 Abbe'* attention was now directed to the tiled o! 

 tricity upon vegetable*. The fn-t experiments on this 

 subject had been made at Kdiiilniridi, in October 17-1-6, 

 by SlrMaimbray, who found that two myrtle trees, elec- 

 trified during the month of October, put forth small 

 branches and blossoms much earlier than other .shrubs 

 that had not been electrified. The Abbe repealed this 

 experiment. He sowed seeds in two pots, filled with 

 the same mould, and k( pt in the s;>n:e place. One of 

 the pots was electrified during I.! days two. lli 

 lour hours a day, while the other remained unclectri- 

 ficd; and it always happened that tin- I pot 



exhibited sprouts two or thn .toner than the 



rest, and threw out larger shoots, and a greater number 

 of them in a given time. 



In extending his experiments to animals, the A bin; 

 Nollet took several pairs of cats, pigeons, chaffinches, 

 sparrows, &c. and placed them in different caucs. Af- 

 ter electrif\ ing one of each pair for five or six hours at a 

 time, he weighed them accurately, and always found 

 that the electrified cat was (>."> or 70 grains lighter than 

 the other, the pigeon from 35 to 38 grains lighter, and 

 the chaffinch and sparrow six or seven grains. Hence 

 he concluded that electricity increases the insensible 

 perspiration of animals. 



I'pon these and other results-, the Abbe Nollel 

 founded a theory of electricity, which was never recei- 

 ved by any other philosopher. He imagined that when 

 an electric is excited, the fluid has two opposite mo- 

 tions, via. an afflux to the electric and an <///tf.r from 

 it. In consequence of the afflux, all light bodies are 

 attracted or carried towards tile electric, while, in 

 consequence of the efflux, all light bodies are carried 

 from the electric or repelled. Hence he w;is obliged 

 to suppose, that every electric, as well as every body 

 which receives electricity, has two different kinds of 

 pores ; one for receiving, and the other for emitting the 

 electric matter. 



About this time a very simple and ingenious theory 

 v. .->> brought forward by Mr Ellicott, a fellow of the 

 Koyal Society of London, which is remarkable as being 

 almost exactly the same as that which -was afterwards 

 so fully illustrated by yl-'.jiinus and Cavendish. After 

 reciting the principal electrical phenomena, he draws 

 from them the following conclusions: 1. That the 

 phenomena of electricity are produced by means of ef- 

 fluvia, wiiich, in exciting the electrical body, are put 

 into motion and separated from it. 2. Thnt the par- 

 tie!'-.- mposing those effluvia strongly repel each other ; 

 and, '!. That there is a mutual attraction between these. 

 part cles and those of all other books. Mr I'.llicott af- 

 terwards proceeds to explain, upon those principles, a 

 variety of electrical experiments. See Phil. Trans. 1748, 

 vol. xlv. p. iy.5. 



louring the years 1747 and 17-18, the attention of phi- 

 losophers was drawn to a series of experiments on the 



Labours of 

 Nollet. 



Theory f 

 Nollet, 



Mr Effi- 

 cott't thw- 

 T- 





