20 BULLETIN 102, UNITED STATES NATIONAL MUSEUM. 
from the prospect of future gain, the maintenance of the situation 
as it now stands is actually costing money. There is no apparent 
reason why fully coordinated development should not look toward 
a fairly complete recovery of at least the leading by-products 1 in 
coal, and this prospect would definitely entail the doubling, if not 
the trebling, of the fuel efficiency derivable. This means that our 
present annual coal output could be made to more than double its 
service, or, accepting the current service requirement as a standard, 
that less than half the output can do the present work and in addi- 
tion make heavy contributions to the supply of fertilizers, motor 
fuel, and chemical products. The aggregate loss, on the basis of 
this very modest estimate, runs well above a billion dollars a year, 
or over $10 for each inhabitant of the United States. (See Table, 
p. IT.) Of such measure is the average man’s pecuniary interest in 
the full utilization of coal. 
Improvement in coal utilization, then, can not be relied upon to 
come from industrial stimulus alone, but must be brought into effect 
as the result of public interest in the matter. The means for start- 
ing toward this accomplishment are set forth in a separate paper, 2 
as lying in the direction of enlarged municipal gas plants, which 
will handle all the coal needed by the community with the pro- 
duction of solid fuel, gas, 3 and the by-products, ammonia, benzol, 
and tar. 
Through the principle of multiple production, therefore, coal can 
be forced to render up its full quota of service. This is a new 
economic force, one scarcely recognized as yet as a principle which 
may be constructively applied. Yet the principle of multiple pro- 
duction has been gaining headway for years, and by means of it the 
multiplying needs of man are being met from practically a station- 
ary range of raw materials. The role of multiple production is 
rapidly enlarging; it represents a principle that must come into 
play more and more to relieve the strain falling upon natural re- 
sources and transportation. Through the agency of chemical knowl- 
edge it serves to create a divergence of products, each the starting 
point of a second diverging series. The principle of multiple pro- 
duction is peculiarly applicable to coal and oil; only by the use of 
this principle, brought into effective action under the guidance of 
a constructive economic policy, can adequate value be extracted from 
these power materials. 4 
1 Nitrogen, benzol, and tar. 
2 Coal : The resource and its full utilization. Bulletin 102, part 4, of this series. 
3 Or the energy may be separated from the commodity values wholly in the form of gas. 
4 The whole matter of multiple production, a term of broader significance than the 
more familiar one of by-product production, is discussed in greater detail in Bulletin 
102, part 6 , of this series. The coming in of multiple production as an economic force 
will cause a revision in some of the popularly accepted ideas of economics, especially as 
regards the operation of the “ law of supply and demand,” as the reactions in the neigh- 
borhood of multiple production are different from those occasioned by volume production. 
