GALVANIC ELECTRICITY . 43 



ject so obscure, although Mr. Davy's experiments have already in 

 some measure justified the boldness of the suggestion. 



SLCTION IV. 



Galvanic, or Voltaic Electricity. 



WE have already hinted at some of the laws and principles of 

 this peculiar mode of accumulating the electric fluid ; fur in most 

 parts of Europe, and in our own country more especially, the fine 

 etherial fluid thus produced, or rendered sensible, is regarded as 

 of au electric nature. From the singularity and magnificence, how. 

 ever, of the effects which under this modification it is well known 

 to be capable of evincing, it is necessary to enter a little more at 

 large into the origin and progress ot the discovery. 



For the earliest insulated facts which paved the way to this science, 

 we are indebted to Professor Galvani ; for their explanation and 

 application to purposes of real utility, we are indebted to Professor 

 Volta : and for the grand and simple law of nature by which they 

 operate in the production of effects, we are indebted to Sir Hum- 

 phry Davy. 



About the year 1790, professor Galvani of Bologna discovered 

 accidentally, that the crural ntrve of a frog cut up for soup for 

 his wife's dinner, contracted and became convulsed upon the 

 application of a knife wetted with water ; as the story is told by 

 other writers, he perceived whilst he was one day dissecting a frog, 

 io a room where some of his friends were amusing themselves with 

 electrical experiments, that the body of the animal was shaken with 

 a violent convulsion, in consequence of a spark being drawn from 

 the conductor of the machine at the time he was touching one of 

 its nerves. Astonished at the phenomenon, and at first imagining 

 that it might be owing to his having wounded the nerve, lie pricked 

 it with the point of his knife, to assure himself whether or not this 

 was the case, but no motion of the frog's body was produced. He 

 now touched the nerve with the instrument as at first, and directed 

 a spark to be taken at the same time from the machine, on which 

 the contractions were renewed. Upon a third trial, the animal re- 

 mained motionless; hut observing that he held his knife by the linn, 

 die, which was made of ivory, he changed it for a metallic one, and 

 immediately the movements took place, which never was the case 

 when he used an electric substance. 



After having made a great many similar experiments with the 

 electrical machine, he resolved to prosecute the subject with atino. 



