from a Natural Magnet. 205 



able to command, (no notice is given of the size of that at Flo- 

 rence) ; there is little doubt, however, from the constancy and 

 brilliancy of the results I have obtained, that, by following the 

 same method, the experiment may be repeated with smaller ap- 

 paratus. At least it is in the highest degree probable that it 

 will be obtained with Dr GOWIN KNIGHT'S immense artificial 

 battery, consisting of 450 bars, 15 inches long, which was em- 

 ployed by Mr FARADAY and Mr CHRISTIE in the prosecution of 

 the Experiments on Magneto-Electric Induction. 



GREENHILL, EDINBURGH, 

 1th May 1832. 



VOL. XII. PART I. D d 



