THE 



PHILOSOPHICAL MAGAZINE: 



COMPREHENDING 



THE VARIOUS BRANCHES OF SCIENCE^ . 

 THE LIBERAL AND FINE ARTS, 

 AGRICULTURE, MANUFACTURES, 



AND , 



COMMERCE. 



BY ALEXANDER TILLOCH, 



BONORAEY member of the KOYAL IRISH ACADEMY, &C. &€. &C. 



" Nec aranearum sane textus Ideo melior quia ex se fila gignunt, nee nost«r 

 vilior quia ex alienis libamus ut apes." Just. Lips. Moiiit. FQlit. HIt^J , ran, i, 





VOL. XXX. 



For FEBRUARY, MARCH, APRIL, and MAY, 1808. 



LOND ON: 



PRINTED FOR JOHN MURRAY, FLEET STREET J AND 



A. CONSTABLE AND CO. EDINBURGH : 



And sold by Richardson; Cadell and Da vies; Longman, HuriTj 



Rees, and Orme; Symonds; Vernor, Hood, and Sharpe; 



Harding; Highley ; London: Bell and Bradfutk, 



Edinburgh : Brash & Reid, and D. Niven, Glasgow: 



and Gilbert and Hedges, Dublin. 



