34 THE SHADOW OF THE WORLD'S FUTURE 
the Census of 1920 was sufficiently comprehensive to 
enable a calculation of high value to be made of the 
possible future. The areas for cities and villages will 
change from 10 to 20 million acres, for public roads 
from 18 to 25, for the railroad right-of-way from 
4 to 6 millions, while the desert will be reduced from 
40 to 39. Thus, according to Mr Baker, the area for 
agriculture can be increased from 503 to 8co million 
acres, in round numbers say about 60 per cent. It 
follows that on the present lines of human development 
the ultimate increase in the yields of agriculture can 
attain only to the same amount. How far the sciences 
of chemistry and physics and the technology of agri- 
culture can advance this increase, is a point which will 
be dealt with later. The way in which the estimate 
touches the problem generally will also be considered 
hereinafter. 
Here it may be mentioned that there are large areas 
in South America, in Africa, in Russia-in-Asia, and 
in Australia, which could be agriculturally developed 
provided certain conditions were fulfilled. "These con- 
ditions are of a varied character. For example in 
South America the physical and economic difficulties 
of conquering the regions drained by the great river- 
systems, and of dealing with the tropical growths 
therein, are enormous. They will involve the posses- 
sion of certain characters in the populations intend- 
ing to occupy them, such as courage, pertinacity 
and intelligence, that are not readily found in suit- 
able combinations. The expenditure of considerable 
amounts of capital is probably also involved, and there 
are other economic difficulties to be faced. These 
operate to limit the utilisation of areas which contain 
necessary physical elements for an advance in the 
world’s total agricultural effort. 
Similar remarks apply to South Africa, and indeed 
Africa generally, and mutatis mutandis to Australia.