FROM WOOD AND COAL. 



"Lavoisier, Crawford, Dalton. and Runiford, in succession, 

 made experiments to determine the quantity of heat evolved 

 in the combustion of various bodies. The apparatus used by 

 the last was perfectly simple, and perhaps the EBoal precis of 

 the whole. The heat was conducted by Battened pipes of 

 metal, into the heart of a body of water, ami was measured by 

 the temperature imparted." 



From the general table of rc-nlts. it is only necessary foi 

 me to extract two, to show the force of the succeeding; remark. 



"The discrepancies in the preceding table, are sufficient to 

 show the necessity of new experiments on the subject." 



As the experiments of M. Lavoisier, Dr. Crawford, and .Mr 

 Dalton. did not comprise any article of fuel except charcoal, a 

 more particular notice of them would be irrelevant to m\ 

 purpose. 



The experiments of Count Romford, to determine the 

 quantity of heat evolved in the combustion of different woods, 

 will alone be examined. In his very jus! remarks, he says, 

 ••.Main persons have already endeavoured to determine tin 

 relative quantities of heat furnished by wood and charcoal ill 

 their combustion; hut the results of their inquiries have not 

 been satisfactory. 



Their apparatus has been too imperfect, nol to leave vast 



incertitude in the conclusions drawn IV their investigations. 



Indeed, the subjeci i^ so intricate in itself, thai with the best 

 instruments, the utmost care i> requisite, lest, after mucb 

 labour, the inquirer should I" forced to content himself \\ith 

 approximations instead of accurate results, and valuations, 

 strictly determined. 



