Voi.'4a 



March 1817. 



No. 227. 



Published the Last Day of every Month, 



[PRICE 2s. 6d.] ^«, 



THE 



^ PHILOSOPHICAL MAGAZINE 

 AND JOURNAL: 



COMPEBHEVDING 



THE VARIOUS BRANCHES OF SCIEN|CE, 



THE LIBERAL AND JFINE ARTS, 



GEOLOGY, 



AfGRICULTURE, 



MANUFACTURES AND COMMERCE. 



NUMBER CCXXVir. 

 For MARCH 1817. 



CONTAINING A PLATE ENGRAVED BY PORTER:— 



To illustrate the Solar Spots which appeared during the Year 

 1816;— -and Mr. Bevan's Improvement on the Sliding-Rule. 



BY ALEXANDER TItLOCH, 



M.R.I. A. F.S.A. Cmx. AND PERTH, ETC. ' 



^1 



I; 



LONDOlf: 



PKIKTED BT RICHARD AND ARTHURTAYLOR, SHOE LANE: 



Andeoldby Cadell iind Davies; LongmAn, Hurst, Rees, 

 Orme,& Brown; Murray; Hiohley; Sherwood and Co.; 

 Harding; Underwood; Simpkin and Marshall; London: 

 Cokstablb apd Co. Edinburgh : Brasu and Reid ; hvu- 

 can; and Penman, Glasgow r< and GiMEEr and Hodges, 



, Dublin.- 



v^^^ 



