There are in the country (1914) about 2,228,000 miles of public roads, of which 10 per cent are “surfaced” roads.  No figures are now available of the number of wagons, horses, automobiles, and other vehicles in use on the roads and streets for purposes of transportation.

Many of our economic problems are presented by these transportation agencies, from the question of opening a new dirt road in a rural township to that of building an inter-oceanic canal, from the question whether to have free public roads or toll roads to that of regulating the railroad rates on the whole railroad system of the country.

Sec. 11. #Raw materials for clothing, shelter, machinery, etc.# The farm lands supply, besides food, a large part of the raw materials for many other goods, such materials as cotton, flax, wool, hides, feathers, lumber, and firewood.  The farm woodlots compose about 200,000,000 acres, and the large forests, public and private, about 350,000,000 acres, a total of about one-fourth the area of the country in forests, containing about one-half of the lumber that the country once possessed.  The economic problem of a sound forestry policy is one of the largest we have to solve.

The most important other sources of raw materials for industry are the mineral deposits in the earth’s surface.[8] This country is stored more bountifully, probably, than is any other country, with the metal ores of iron, copper, lead, zinc, gold, and silver.  Aluminum is the most abundant metal, composing about 8 per cent of the crust of the earth, but by present methods it can be extracted only at considerable cost from certain compounds that are limited in amount.  The details as to our metal stores are too complex for fuller treatment here, and may be found in treatises on economic geology or on industrial geography.  The determination of wise policies as to the use of these stores involves many economic problems, private and public.

Another great class of material wealth is in the form of tools, machinery, and other agencies for carrying on the industrial processes of farming and of manufacturing.  These are sometimes called instrumental goods, or the industrial equipment.  Still another class consists of the great mass of completed direct goods, such as houses to live in, libraries, museums, school buildings, theaters, all kinds of buildings and equipment for pleasure and entertainment, parks, and pleasure resorts in mountains, at lakes or sea shore.  The possession and use of these forms of wealth give rise to some economic problems of public ownership and to others connected with the institution of private property in general, as sketched in the following chapter.

[Footnote 1:  It is to be observed that these figures appear under the general title of Part I, “Estimated valuation of national wealth:  1850-1912,” and the tables are spoken of (volume on Wealth, Debt, and Taxation, p. 20) as “estimates of the aggregate wealth of the nation as prepared by the United States censuses,” but the tables themselves are described (pp. 23-25) as the “estimated true valuation of all property,” this phrase being used as equivalent to “wealth.”  For the definitions of wealth and property see Vol.  I, pp. 264-265.]