Vol. 38. 



September 1811. 



No. 161. 



Published the Last Day of every Month , 

 [PRICE 2s. 6d<] 



THE 



^i' PHILOSOPHICAL MAGAZINE 



COM,PREHtiNDINO 



THE VARTOUS BRANCHES OF SCIEN^CE, 



THE LIBERAL AND FINE ARTS, 



GEOLOGY, AGRICULTURE, 



MANUFACTURES AND COMMERCE. 



NU.MBER^'CLXI. 

 For SEPTEMBER 181 1. 



iljiM CONTAINING THE FOLLOWING ENGRAVINGS BY PORTER- 



1. A Representation of the Comet nov/ visible in Ursa Major. 



2. Sir Howard Douglas's Patent Reflecting Semicircie. 



BT ALEXANDER TILLOCH, 



M.K.l.A. P.S.A. EDIM. AND PERTH, &C. 



LONDON: 



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