The Conductors of the Philosophical Magazine have to acknowledge the editorial 

 assistance rendered them hy their friend Mr. Edward W. Brayley, F.L.S., 

 F.G.S., Assoc. Inst. C. E. ; Member of the American Philosophical Society, 

 and Corresponding Member of the Philosophical Society of Basle, &c. Librarian 

 to the London Institution- 



