.30| 7.76|
|---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----|
| |"B" or | | | | | | | | | | |
| |Lower | | | | | | | | | | |
| |Kittan-| Eureka,| | | | | | | | | |
|Pa | ning | No. 31 |16.71|77.22|84.45|4.25| 3.04|1.28| .91| 6.07| .56|
|---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----|
| |Indiana| | | | | | | | | | |
|Pa | Co. | |29.55|62.64|79.86|5.02| 4.27|1.86|1.18| 7.81| 2.90|
|---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----|
|W. | Fire | Rush | | | | | | | | | |
|Va | Creek | Run |22.87|71.56|83.71|4.64| 3.67|1.70| .71| 5.57| 2.14|
=========================================================================

Table 39 gives for comparison the ultimate and proximate analyses of
certain of the coals with which tests were made in the coal testing
plant of the United States Geological Survey at the Louisiana Purchase
Exposition at St. Louis.

The heating value of a fuel cannot be directly computed from a proximate
analysis, due to the fact that the volatile content varies widely in
different fuels in composition and in heating value.

Some methods have been advanced for estimating the calorific value of
coals from the proximate analysis. William Kent[38] deducted from
Mahler's tests of European coals the approximate heating value dependent
upon the content of fixed carbon in the combustible. The relation as
deduced by Kent between the heat and value per pound of combustible and
the per cent of fixed carbon referred to combustible is represented
graphically by Fig. 23.

Goutal gives another method of determining the heat value from a
proximate analysis, in which the carbon is given a fixed value and the
heating value of the volatile matter is considered as a function of its
percentage referred to combustible. Goutal's method checks closely with
Kent's determinations.

All the formulae, however, for computing the calorific value of coals
from a proximate analysis are ordinarily limited to certain classes of
fuels. Mr. Kent, for instance, states that his deductions are correct
within a close limit for fuels containing more than 60 per cent of fixed
carbon in the combustible, while for those containing a lower
percentage, the error may be as gre