PARKER, HOLMES 
AND CAMPBELL. 
| INTRODUCTION. 17 
coals, and that the quality of many of these coals may be improved by 
washing. 
(2) Most of the American bituminous coals and lignites can be used 
as a source of power in a gas-producer plant. 
(3) As indicated by comparative tests of 14 bituminous coals from 
9 States, the power efficiency of these coals when used in the gas- 
producer plant is two and one-half times greater than their efficiency 
when used in the steam-boiler plant; or, in other words, 1 ton of these 
coals used in the gas-producer plant has developed, on a commercial 
scale, as much power as Q l\ tons of the same coal when used in the 
ordinary steam-boiler plant. 
(4) Some of the lignites from undeveloped but extensive deposits in 
North Dakota and Texas, when tested in the gas producer and gas 
engine, have shown unexpectedly high power-producing qualities, such 
as promise large future developments in those and other States. 
(5) Some of the American coals, and the u slack" produced in min- 
ing these coals, can be briquetted on a commercial basis. 
The value of the results of these investigations is, of course, not 
limited to the coal-producing sections of the countiy, but extends 
through every State and Territory where coal or other mineral fuel 
is used as a source of power. Thus, in the New England States no 
coal is mined; but in the year 1900 the steam power produced through 
the consumption of coal and used for manufacturing purposes in these 
States cost approximately $50,000,000. The development of this 
power through the more efficient methods suggested by these investi- 
gations would mean a saving to the manufacturers in these States of 
$15,000,000 to $20,000,000 per annum. 
As another illustration of the way these investigations may influ- 
ence the affairs of the nation as a whole, it may be stated that there 
were used in the naval vessels of the United States in 1903 approxi- 
mately 500,000 tons of coal, costing $2,500,000. If the future gas 
producer and gas engine can be substituted on our battle ships and 
cruisers for the existing steam boilers and engines, the saving in the 
cost of coal would be not less than $1,000,000 per annum, or, what 
would be of far greater importance, the distances traversed by each 
ship without coaling would be more than doubled. 
The fact that the coals and other mineral fuels used in the United 
States during 1904 cost the consumers approximately $1,500,000,000 
indicates the magnitude and importance of the problems under inves- 
tigation b}^ the Geological Survey in connection with its coal-testing 
plant. 
Bull. 261—05 2 
