226 INDUSTRIAL REVOLUTION AND WAGES 
may be said, however, with some force, that altho these ele- 
ments may account for the long-time growth of industry, 
they do not entirely explain the recent rapid increase in out- 
put per worker. It is, nevertheless, true that these natural 
features are basic elements in this increase; they have pro- 
vided a convenient source not only of raw materials to which 
machinery has been applied with fruitful results, but as well 
of the raw materials out of which the machines themselves 
have been made and the fuel with which to run them. In 
other words, our vast natural resources have been the basis 
of our abundant supply of capital in the form of productive 
equipment, which in turn has aided in bringing about the 
rapid mechanization of industry. At the same time other 
physical and political features—large population, the diver- 
sity of regional demands, and the absence of inter-regional 
trade restrictions, such as tariffs—have furnished a domestic 
market exceeding in magnitude and diversification that of any 
other industrial nation. The magnitude of the market, the 
abundance of capital, and the education of American con- 
sumers by persistent advertising to accept standardized 
articles have encouraged the development of mass produc- 
tion, which in turn has permitted a reduction in unit costs. 
The growth of large corporations, the resort to mass pro- 
duction, and the movement toward integration of industrial 
operations in process in this country during recent years are 
too familiar to require evidence. . . . 
Large-scale production is especially economical where large 
quantities of the same products can be produced. The mag- 
nitude of our domestic market and the willing acceptance of 
standardized articles make feasible such repetitive processes. 
Large-scale production is dependent upon the machine 
process, and the increasing use of machinery and power and 
labor-saving devices has accompanied the growth in size of 
productive units. . . . 
Power has been substituted for labor not only through ma- 
chines of production but also in the form of automatic con- 
veying and loading devices. In this connection contributions