fact that readily available timber was becoming less and less
accessible. Portland cement is manufactured in larger amounts and has
a wide use in the building industry. During the years 1900-9 the
average production was 33,000,000 bar.; in 1916 it reached 95,000,000
barrels. The production of tin plates, terne plates, and taggers
tin showed a steady development; in 1910 the production amounted
to 1,370,788,000 lb. and in 1919 to 3,301,624,000 lb. An export
trade was developed, the export of domestic product rising from
26,168,000 lb. to 527,462,000 lb.; import of this product has
practically disappeared.
Table 14. Individual Industries; dollars in millions.
| 1919 | 1914 | Per cent. increase | |
| Automobile bodies and parts | 674 | 130 | 418 |
| Automobiles | 2,388 | 503 | 373 |
| Boots and shoes | 1,152 | 502 | 129 |
| Bread and other bakery products | 1,406 | 492 | 186 |
| Butter | 583 | 243 | 140 |
| Cars and general shop construction and repairs | |||
| by steam railway companies | 1,278 | 514 | 149 |
| Cars, steam railway, not including | |||
| operations of railway companies | 540 | 195 | 176 |
| Chemicals | 695 | 200 | 242 |
| Clothing, men's | 1,158 | 458 | 153 |
| Clothing, women's | 1,184 | 474 | 150 |
| Confectionery and ice cream | 637 | 210 | 203 |
| Cotton goods | 1,878 | 677 | 177 |
| Electrical machinery, apparatus and supplies | 1,014 | 335 | 203 |
| Flour-mill and grist-mill products | 2,193 | 878 | 152 |
| Food preparations not elsewhere specified | 663 | 219 | 203 |
| Foundry and machine-shop products | 2,321 | 867 | 167 |
| Furniture | 574 | 266 | 116 |
| Iron and steel, blast furnaces | 794 | 318 | 118 |
| Iron and steel, steel works and rolling-mills | 2,813 | 919 | 206 |
| Knit goods | 686 | 259 | 165 |
| Leather, tanned, curried and finished | 929 | 367 | 150 |
| Lumber and timber products | 1,401 | 715 | 96 |
| Lumber, planing-mill products, not including | |||
| planing-mills connected with saw-mills | 561 | 308 | 82 |
| Oil and cake, cottonseed | 570 | 212 | 169 |
| Paper and wood pulp | 794 | 332 | 139 |
| Petroleum refining | 1,645 | 396 | 315 |
| Printing and publishing, book and job | 601 | 307 | 96 |
| Printing and publishing, newspapers and periodicals | 892 | 496 | 80 |
| Rubber goods, not elsewhere specified | 980 | 224 | 338 |
| Shipbuilding, steel | 1,454 | 66 | 2,103 |
| Silk goods | 685 | 254 | 170 |
| Slaughtering and meat-packing, wholesale | 3,714 | 1,454 | 155 |
| Smelting and refining, copper | 633 | 444 | 42 |
| Sugar, refining, not including beet sugar | 731 | 289 | 153 |
| Tobacco, cigars and cigarettes | 886 | 315 | 181 |
| Worsted goods | 676 | 276 | 145 |
The cost of new buildings in the principal cities is estimated by the U.S. Geological Survey as follows:— 1910, $726,437,000; 1911, $687,507,000; 1912, $738,990,000; 1913, $673,221,000; 1914, $619,752,000; 1915, $700,413,000; 1916, $839,706,000; 1917, $569,011,000; 1918, $344,622,000; 1919, $1,019,491,000. The figures show that, although the war checked building, the total value of the buildings constructed in 1919 was much greater than in any preceding year; the cost for 1919 was swollen by high prices and does not accurately represent the volume of new building, measured by physical units.
After 1909 there was but a slight increase in the number of manufacturing establishments, notwithstanding the gain in the number of wage-earners and value of product. In 1914 there were 275,791 establishments, with 7,036,337 wage-earners, and products valued at $24,246,000,000, or $87,916 per establishment; in 1919, 288,376 establishments with $62,588,000,000, or $217,000 per establishment. In 1914, 2,476,006 wage-earners, or more than one-third (35.2%), were in 3,819 establishments, an average of nearly 650 workers per establishment; nearly one-half (48.6%) of the value of the product was manufactured in this small group of establishments. Of the 8,263,153 persons engaged in manufactures in 1914, 6,613,466, or 80%, were males, and 1,649,687, or 20%, were females.
Minerals.—The value of mineral products, as estimated by the U.S. Geological Survey, increased from $1,992,406,000 in 1910 to $5,543,456,000 in 1918. Nearly three-fourths was represented in 1918 by five products, as follows (in millions of dollars):—pig-iron 1,181 (412 in 1910); bituminous coal 1,492 (469 in 1910); anthracite 336 (160 in 1910); copper 471 (137 in 1910); petroleum 704 (128 in 1910). Lead increased in value from $30,855,000 in 1910 to $76,667,000 in 1918; zinc from $27,268,000 to $89,618,000; aluminum from $8,956,000 to $41,159,000; natural gas from $70,756,000 to $157,000,000; and cement from $68,752,000 to $113,555,000. Platinum had a remarkable development, the product increasing from 8,665 oz., valued at $478,688, in 1915 to 59,753 oz., valued at $6,417,980, in 1918.
The production of iron ore increased from 56,889,734 long tons in 1910 to a maximum record of 77,870,553 tons in 1916. In 1918 the production was slightly less, 72,021,202 tons. In the latter year this was manufactured into 39,054,644 tons of pig-iron. More than half of the iron ore produced is mined in Minnesota amounting to 43,263,240 tons, followed by Michigan 17,587,416 tons; Alabama mined 6,121,087 tons. In 1912 the National Conservation Commission estimated the total supply of iron ore profitable to mine at 4,784,930,000 long tons, and 75,000,000,000 tons not worth mining. According to this estimate the profitable ore deposits might be exhausted in 60 years, allowing for no increase in annual rate of production. The ore deposits being worked in 1921 were for the most part on the surface in the region of the Great Lakes. (See Iron and Steel.)
The production of anthracite coal in 1910 was 75,433,246 tons (of 2,240 lb.); in 1919 78,653,751 tons, an increase of 4 per cent. The bituminous coal production in 1910 was 417,111,142 short tons as compared with 459,971,070 tons in 1919 (preliminary estimate of the Geological Survey), a gain of 52 per cent. About two-thirds of the coal consumed goes into the production of power, about equally divided between the industries and transportation; about one-sixth is used as a raw material, for making products employed industrially, as coke, gas, and coal-tar products; and about one-sixth for heating homes and other buildings. (See Coal.)
The mining of copper does not follow a regular ascending curve of production. It reached the high point in 1906, 409,735 long tons; declined in 1907; rose to 487,925 tons in 1909; again declined in 1910; rose to 555,031 tons in 1912; fell to 513,454 in 1914; and again advanced to 860,648 tons in 1916. In 1916 more than one-third was produced in Arizona, which has become the principal producing state. In the same year it was estimated by The Mineral Industry that the world's production was 1,373,200 long tons. After 1916 there was a marked decline in production. (See Copper.)
The increased demand for gasoline for automobiles raised the price and led to vigorous efforts to discover new supplies of petroleum. During 1908-19 the production in California more than doubled; in Texas trebled; in Oklahoma more than doubled; in Wyoming new oil-fields were opened. The total production in 1920 was 443 million barrels, as against 281 millions in 1915 and 179 millions in 1908. For details see Petroleum. The Director of the U.S. Geological Survey estimated in 1920 that the country's oil resources were over 40% exhausted, and that the supply at the existing rate of consumption would be exhausted within 20 years (see Fuel). Between 1908 and 1916, when active exploration was carried on, the reserve was enlarged by only 1,200 million barrels. Attention has been turned to the possibility of extracting petroleum from the oil shales of Utah, Colorado and Wyoming.
The volume of natural gas produced has risen steadily since the beginning of the century. In 1910 the production was 509,000 million cub. ft., and in 1919, 1,726,000 million cubic feet. Natural gas is found in 23 states, but chiefly in West Virginia, Pennsylvania, Ohio, Oklahoma, and California. Some 2,100 cities and towns are supplied. One-third is used for domestic purposes and two-thirds for industrial plants. The production in 1910 and 1918 is shown in Table 15. The average value in 1910 was 13.9 cents per 1,000 ft. giving a total value of the product, $70,800,000; in 1918, 21.3 cents per 1,000 ft. and $154,000,000 total value. About 15,444,000 ac. of land were controlled by natural gas producers in 1917.
Table 15. Natural Gas Production; in million cub. ft.
| 1918 | 1910 | |
| West Virginia | 265,000 | 191,000 |
| Pennsylvania | 123,000 | 127,000 |
| New York | 8,000 | 6,000 |
| Ohio | 61,000 | 48,000 |
| Louisiana and Texas | 49,000 | 8,000 |
| Illinois | 4,000 | 7,000 |
| Oklahoma | 124,000 | 50,000 |
| Kansas | 28,000 | 59,000 |
| California | 40,000 | 3,000 |
| Other states | 19,000 | 10,000 |
| 721,000 | 509,000 |
The production of gold reached its maximum in 1915, valued at $101,035,700; during the war it declined owing to advancing prices of materials and labour and the decreased purchasing power of gold (see Gold). In 1919 the production was valued at $58,488,800, less than in any year since 1897. California furnished $17,398,000; Colorado $9,736,400; Alaska $9,036,000. Silver likewise reached its maximum in 1915, amounting to 74,961,075 fine Troy oz., valued at $37,397,300. In 1919 the bullion produced was less,
