144 



Introduction to the Study of Science 



Example. A coal contains : 



Substituting the proper figures in the formula we have 



.5594 X 14,544 + 62,028 x (.0525- ^.\ + 4050 X .0435 



or 8334.90 + 1,680.27 + 176.17 = 10,293, 



the B. T. U. This calculated value is approximate, but close enough 

 for practical purposes. Problems may be based upon the table, which 

 gives typical fuels, and coals from well-known fields of our country. 



FIG. 39. Table of fuels, their composition, and heat value 

 in B. T. U. 



