ADVERTISEMENT. 



THE basis of the following Essay is an ar- 

 ticle that was published in the tenth volume 

 of Dr. Brewster's Encyclopaedia. The commend- 

 ations which it received, wjhile under that form, 

 from those whom I supposed competent to de- 

 cide upon its merits, have induced me to reprint 

 it, although with considerable additions and cor- 

 rections, which will, I hope, render it more deserv- 

 ing of the public favour. My present residence 

 in the metropolis has given me the opportunity of 

 examining several works on galvanism, which I had 

 not before been able to procure, and I have also en- 

 deavoured to profit by the remarks of my scien- 

 tific friends, so as to rectify the inaccuracies into 

 which I had fallen, and to render those parts more 

 perspicuous, which were thought to be obscure. 



Great Coram Street, 

 June 24, 1818. 



218 



