om the
ultimate analysis.

Ultimate analyses are given on both a moist and a dry fuel basis.
Inasmuch as the latter is the basis generally accepted for the
comparison of data, it would appear that it is the best basis on which
to report such an analysis. When an analysis is given on a moist fuel
basis it may be readily converted to a dry basis by dividing the
percentages of the various constituents by one minus the percentage of
moisture, reporting the moisture content separately.

_Moist Fuel_ _Dry Fuel_

C 83.95 84.45
H 4.23 4.25
O 3.02 3.04
N 1.27 1.28
S .91 .91
Ash 6.03 6.07
------
100.00

Moisture .59 .59
------
100.00

Calculations from an Ultimate Analysis--The first formula for the
calculation of heating values from the composition of a fuel as
determined from an ultimate analysis is due to Dulong, and this formula,
slightly modified, is the most commonly used to-day. Other formulae have
been proposed, some of which are more accurate for certain specific
classes of fuel, but all have their basis in Dulong's formula, the
accepted modified form of which is:

Heat units in B. t. u. per pound of dry fuel =

O
14,600 C + 62,000(H - -) + 4000 S (18)
8

where C, H, O and S are the proportionate parts by weight of carbon,
hydrogen, oxygen and sulphur.

Assume a coal of the composition given. Substituting in this formula
(18),

Heating value per pound of dry coal

( .0304)
= 14,600 x .8445 + 62,000 (.0425 - -----) + 4000 x .0091 = 14,765 B. t. u.
( 8 )

This coal, by a calorimetric test, showed 14,843 B. t. u., and from a
comparison the degree of accuracy of the formula will be noted.

The investigation of Lord and Haas in this country, Mabler in France,
and Bunte in Germany, all show that Dulong's formula gives results
nearly identical with those obtained from calorimetric tests and may be
safely applied to all solid fuels except cannel coal, lignite, turf and
wood, provided the ultimate analysis is correct. This practically limits
its use to coal. The limiting features are the presence of hydrogen and
carbon united in the form of hydrocarbons. Such hydrocarbons are present
in co