VOL. 21. 



May 1805. 



Published the Last Day of every Mo/ith, 

 [PRICE 2s. 6d.] 



THE 



PHILOSOPHICAL MAGAZINE: 



COMPREHENDING 



THE VARIOUS BRANCHES OF SCIENCE, 



THE LIBERAL AND FINE ARTS, 



AGRICULTURE, MANUFACTURES, 



AND 



COMMERCE. 



NUMBER LXXXIV. 

 For M J Y 1805. 



ILtUStRATED WITH THE FOLLOWIN'G ENGRAVINGS, 



BV LOWRY; 



I. The Chevalier Eoelcrantz's Safety-Valve for Steam Engine 



Boileis (Described in our last Number). I"|if^ 



A 4to plate, containing magnified Representations of the P^'jJxjjI.^ 



rasitic Plant which causes the Blight in Corn, engraved by^W 



Permission of the lit. Hon. Sir Joseph Banks, P.R.S. from^|^\ 



the original drawings. — (.-Another 4to P-' ite on this subject, 'j^ |.^ 



executed in the same sTiperlor Style with the one now given, 



was intended for the present Number, but In consequence olilJ^^V^ 



the indisposition of Mr. Lowry, it must be deferred for a^^^' 



, ,. future Number.) ^^^vs 



'^*^* A Constant Reader will find the Electrometer he wants ^ 



described in our nth Vol. Page a^i. 



■ ■ - '>■ ■ ■ ■■■ .1 — — 



.^, ^,^^ BT JLEXJNDER TILLOCH, ^^; 



^.i';,^!) HONORARY MEMBER OP THE ROYAL IRISH ACADEMY, &C. &C.&:C.'»^*^^'^ 



LONDON: 



Priittcd L'l/ R. Taylor an/i Cu„ 38, Sloe. Lane, Fled Sliecl, 

 ron A. TILLOCH : 



/r' !& And sold by Messrs. Richardson; Cadell and D.wies ; Long-/l^.v4 

 iiv*'^^ MAN, Hurst, Rf.es, and Orme ; Symonds ; Murray ; Hi<'»-f^!:':;^!i 

 ^^^ ley; Veunor and Hood; Harding; London: Bkll andij^.'^'jW 

 Bradfute, Edinburgh; Brash and Reid, and D. Nevin, 

 Gla?gow ; and Gilrekt and HnncEs, Dublin. 5 





;^'!'^^^<^^^^s>.-Zr-''i^:^:^-^^ '- ^> W- iv'^^lfcy" 



