Vol. 54. 



Oct. 1819. 



No. 258. 



Published the Last Pay of every Mo7ith, 



[PRICE 2s. 6d.] 



J 



THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL: 



Cr.MPBEkBHDIilO 



THE VARIOUS BRANCHES OF SCIENCE^ 



THE LIBERAL AND FINE ARTS, 



GEOLOGY, 



AGRICULTURE, . 



MANUFACTURES AND COMMERCE. 



. ;NUMI|ER. GCLVIII. 

 For OCTOBER 1819. 



WITH AN E;XGR/\VING BY PORTER I 



?{t^^ lUuEtratlve of , Captain SABifJE's Paper on Irregiilarities ob- 

 served in the Direction of the Compass Needles of the 

 Isabella and Alexander ir. the late Voyage of Discovery ; and 

 Mr. Scoresby's Anomaly in the Variation of tJie Magnetic; 

 ^|!t^ Needle as observed on Ship-board. • , I 



BY ALEXANDER TILLOCH, 



n.v..\ji. M.G.S. M.n.A.s. Mysicn, vs.a. edjn. ANDrEUTHj he. 



' .^ LONDON: 



M IK TED BY lllCHAS,0 AND ARTHUR TAYLOR, SHOB-LANE : 



And sold by Cadbll and Daties ; Lokgman, Hurst, Rees, 

 OftMh, k Brown; Hirhley; Sherwood and Co.; Harding;) 

 Underwood: SiMPxinandMARSHALL; London: Constable' 

 and Co. Edinburgh: Brash and Reid; Duncan; and Pen- 

 man, Glasi^ow: and Gilbert and Hodges, Dublin. 



