^26 Outlines of a V'lciu of Galvaniftn. 



fee as well as the owls to catch their prey ; and in the day- 

 time, like thoie birds, they arc dazzled hv the too great fplcn- 

 dour of the liffht. But at that lime tlicy have no need of 

 very acute fight, as they feldoui leave their web ; and, when 

 thev do, are conduced back to it by their delicate fenie ot 

 touching. Befides, thev feldom have occafion for it in the 

 day-time, as their webs are then too vifible to the iniefts 

 which they catch ; fo that the latter can be belter on their 

 guard againft them than they can during the twilight. 



Lin. OntHnes of a Viciu of Ga/i'<7ni/m, chirfly cxtradi'd 



from a Coiirfc of Lcclurfs on the' Galvanic Phanomina, 



read at the theatre of the Rojal Injiilution by Mr. Day v *. 



I. Hiflor'ical LitrudtiBion. 



§ I. X HE fciencc relating to the peculiar aAion of dif- 

 ferent conduftors of dedtricity on each other, hns lately ex- 

 cited a conliderable degree of attention in the philofophical 

 world. 



Owing its origin to the pluvnomenou difcovered by Gal- 

 vanif, the prodii6lion of niul'cular contraction by the api- 

 plication of metals to the nerves and nuifcles of animals, it 

 has derived its name from that philofopher. 



Galvanifm was at firll limited in its apiilication to organ- 

 ized bodies; but, in confei]uence of the labours and inven- 

 tive genius of experimcntalilis, our contemporaries, it has 

 gradually become connefted with ehemilirv and general phy- 

 fics ; it has aflbrded powerful inCtruuients of inveltigaiion ; 

 and its operations have been traced throughout the whole ot 

 nature. 



In giving an account of the progrefs of this feience, in its 

 relation to the powers of the human mind, it will be fuRi- 

 cient to notice fuch experiments only as have derived their 

 origin from extenfive theoretical views, and fuch difcoveries 

 as have led to accurate generalifations of phicnomena already 

 known. 



Though the hiftorv of galvanifm extends only through the 

 period of the lall: nine years, vet we niay notice in it four 

 epochs, each of them dillinguilhed by the development of 



* From the Journ ils of the B.o\\d bijliiu/'imi of Great Briiaiit. 



•\ The 111 II faft relating ro the action of metals on the animal organs, 

 was obfcrved by Siilzcr, who has del'cribed tlie fenfation "f talle produced 

 by the contncl of lc;id and filver with the tongue, in his IbcorU des Plaijirs, 

 publiflicJ in 1767. 



fafts. 



