78 



THE NATURE AND 



[SECT. n. 



lowing table, they serve here to indicate that the observed numbers are probably 

 too low for the true ones. 1 



111. EXPERIMENTS ON THE FORCE OF THE VAPOUR OF SULPHURET OF CARBON, 



BY M. CAGNIARD DE LA TOUR. 



The irregularities in all M. Cagniard de la Tour's experiments would be in part 

 occasioned by the expansion of the tubes under such high pressures and tem- 

 peratures ; hence, to attempt a minute comparison would only show a want of 

 attention to physical effects too common in such inquiries. The usual practice of 

 attempting to supply want of observation by minute calculations, is one of the 

 great defects of the present mode of scientific inquiry, as applied to improve the 

 scientific arts. 



112. The forces of various other substances have been tried, but not with 

 much attention to the selection of such as are adapted for the acting vapours in an 

 engine ; as, for that purpose, one should be chosen which affords the highest power 



1 The rule in logarithms for sulphuret of carbon, by which the calculated numbers in these 

 tables were found, is 



log. /=6 (log. (t +280) - 2-34488) 

 to the point where the liquid becomes wholly vapour. 



