262 Mr. E. M. Clarke's Description of 



ders an iron wire indifferent to nitric acid, prevents the oxida- 

 tion of this metal during the decomposition of water by means 

 of the galvanic battery. I shall not for the present enter 

 further into the theory to be deduced from these facts, as I 

 am satisfied many further researches still require to be made. 



LIV. Description of E. M. Clarke's Magnetic Electrical 

 Machine. 



To the Editors of the Philosophical Magazine and Joiirnal. 



Gentlemen, 



FROM the time Dr. Faraday first discovered magnetic 

 electricity to the present, my attention, as a philosophical 

 instrument maker, has been entirely devoted to that important 

 branch of science, more especially to the construction of an efK- 

 cacious magnetic electrical machine, which after much anxious 

 thought, labour and expense, I now submit to your notice. 



