and the Economy of Fuel. 



101 



the saving of fuel was so much increased as to show in 

 a decisive manner the superiority of the new boiler. 



The difference in the expense of fuel in these experi- 

 ments with these two boilers is by no means infconsid- 

 erable : it amounts to above 14 per cent, and would 

 have amounted to more, if more time had been allowed 

 for heating the water in the experiment with the new 

 boiler ; for it is easy to show (what indeed was clearly 

 indicated by all the experiments) that, in causing liquids 

 to boil, the quantity of fuel will be less in proportion as 

 the time employed in that process is long, or, which 

 is the same, as the fire is smaller ; and the saving of 

 fuel arising from any given prolongation of the process 

 will be the greater, as the fire-place is more perfect, 

 and as the means used for confining the heat are more 

 effectual. 



Though the general results of these two sets of ex- 

 periments afforded abundant reason to conclude that 

 the alterations I had introduced in arranging the new 

 boiler were real improvements, yet, when I compared 

 the quantity of fuel consumed in the experiments with 

 this new boiler with the much smaller quantities, in 

 proportion to the quantity of water, which were em- 

 ployed in some of my former experiments with kitchen 



