Sioux City Academy of Science and Letters. 179 
a blast lamp being applied, as recommended by Dumble 
in his treatise on the Brown Coals of Texas. In this 
work it was thought best to subject the lignites to the 
strictest tests applicable to bituminous coals in order to 
properly ascertain their true relative value. 
The percentage of water in freshly mined samples 
would equal the percentage lost in dry air plus the per- 
centage retained in dry air, and is seen from Tables I and 
II to average above 22 per cent. Manifestly, then, these 
fuels come within the strict chemical classification of 
lignites. 
Comparison with Table IV, of analyses of lignites 
from other localities, shows that the Dakota County lig- 
nites are fair representatitves in so far as proximate 
composition is concerned. 
It is evident that the ratio of 1 between the fixed 
carbon and volatile, combustible matter is too low a 
limit to establish as a minimum for a fuel that shall be 
classed as a bituminous coal, and there are many 
instances in which the percentage of fixed carbon is 
slightly greater than that of volatile, combustible matter, 
and yet the material is called a lignite. Table III shows 
that this is the case in all the instances. These, physi- 
cally, are not lignites, nor are they brown coals. They 
are lignitic bituminous coals that are finding a wide use 
for domestic and steam purposes, and in the interests of 
finding the relative value of the Nebraska materials they 
were studied in the laboratory under the same condi- 
tions. 
Proximate constituents—The percentage of moisture 
retained by the Nebraska lignites in dry air is not exces- 
sive, but somewhat higher than that contained in good 
orades of bituminous coals. The percentage of volatile, 
combustible matter is as high as that usually found in 
highly bituminous coals. The percentage of fixed car- 
bon, chiefly upon which the value of a coal as a fuel 
depends, is rather low, although as high as that of some 
of the Texas lignites which have been recommended as 
fuels. The percentage of ash is higher than that of most 
lignites or bituminous coals. This indicates the deposi- 
tion of large quantities of mineral salts from solution in 
the water with which the fresh lignite is saturated. 
