Vol. 57. 



^^k Published the Last Day of every Months 



^1^ [PRICE 2s. 6d.] 



No. 278- 



THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL: 



COMPREHENDING 



THE VARIOUS BRANCHES OF SCIENCE, 



THE LIBERAL AND FINE ARTS, 



GEOLOGY, 



AGRICULTURE, 

 MANUFACTURES AND COMMERCE. 



NUMBER CCLXXVIII. 

 For JUNE 1821. 



'^k 



WITH A PLATE BY PORTER, 



fi^^M Representing a Double Canal Lock, originally proposed for the 



■ ' '" Regent's Canal, by Mr. R. H. Gower ; and a Modification of 



Electro-Magnetic Apparatus, by Mr. Tat.obi. 



BY ALEXANDER TILLOCH, LL.D. 



•''A M.R.I. A. M.O.S. M.A.S. F.S.A. EDIN. AND PERTH ; C0RRE3P0N DI NG MEM- 

 ^ BER OF THE BOYAL ACADEMY OF SCIENCES, MUNICH ; AND OF THE^ 

 -.;* ACADEJIY OP SCIEfiCES, LITERATURK AND ARTS, LEGHORN, &C. &C. 



L ND ON: ■ ' \ 



PRINTED BY RICHARD AND ARTHUR TAYLOR, SHOE-LANE : 



4^^ And sold by Cadell and Davies ; Longman, Hurst, Rees, 

 1^^ Orme, & Brown ; Highley; Sherwood and Co.; Harding ; 

 Underwood; SiMPKiNandMARSHALL ; London: Constable 

 and Co. Edinburgh: and Prnman, Glasgow. 



-v i-, - 



