TABLE 4.-PRODUCTS BY KIND, QUANTITY, AND VALUE, FOR THE UNITED STATES: 1939 AND 1937 No detailed production statistics were collected for this industry; therefore, table 3 shows all production statistics available.

TABLE 5.-WAGE EARNERS ENGAGED IN MANUFACTURING, BY MONTHS, FOR THE UNITED STATES, 1939, 1937, AND 1929, AND FOR OHIO, 1939

COLD-ROLLED STEEL SHEETS AND STRIP AND COLD-FINISHED STEEL BARS MADE IN PLANTS NOT OPERATED IN CONNECTION WITH HOT-ROLLING MILLS

[A preliminary report for this industry was issued November 16, 1940]

Description of the industry. This industry, as constituted for census purposes, embraces establishments primarily engaged in cold-rolling steel sheets and strip and cold-finishing steel bars from purchased hotrolled material. These commodities are also produced to a large extent by establishments classified in the "Steel works and rolling mills" industry which operate both hot- and cold-rolling mills. No detailed product statistics are given in this report, but the total production of cold-rolled steel sheets and strip and cold-finished steel bars, in all industries in which they are made, is shown in the "Steel works and rolling mills" industry report, "Principal Manufactures from Rolling Mill Products, Except Tin Plate and Terneplate and Wire and Wire Products."

Statistics for earlier years. As this industry was established as a separate classification for the census

4 See GENERAL EXPLANATIONS-Wage earners and wages.

Value of products less cost of materials, supplies, containers, fuel, purchased electric energy, and contract work. See GENERAL EXPLANATIONS-Value added by manufacture.

TABLE 3.-VALUE OF PRODUCTS, FOR THE UNITED STATES: 1939 AND 1937

TABLE 4.-PRODUCTS, BY KIND, QUANTITY, AND VALUE, FOR THE UNITED STATES, 1939 AND 1937 Detailed production statistics shown in report for 'Steel works and rolling mills;" therefore, no figures are given for this industry for tables 3 and 4.

COLD-ROLLED STEEL SHEETS, ETC.

301

TABLE 5.-WAGE EARNERS ENGAGED IN MANUFACTURING, BY MONTHS, FOR THE UNITED STATES, 1939 AND 1937, AND BY STATES, 1939

Group 15.-NONFERROUS METALS AND THEIR PRODUCTS

The industries as a group. This group comprises industries engaged in the production of nonferrous metals from the ores or from scrap metals; in the refining or alloying of such metals; and in the manufacture, from these metals or alloys as basic materials, of finished products or products for use in further manufacturing processes.

The group figures for 1937 have been revised, on the one hand, to exclude data for the "Chemical Fire Extinguishers" and "Needles, Pins, Hooks and Eyes, Slide and Snap Fasteners" industries, also for establishments formerly classified in the "Jewelry" industry whose primary products were nonprecious jewelry, all of which were allocated to the "Miscellaneous Industries" group. On the other hand, the figures have been revised to include data for the "Lapidary Work” and "Engraving on Metal (Except for Printing Purposes)" industries, which were transferied from the "Miscellaneous Industries" and the "Printing, Publishing, and Allied Industries" groups, respectively, and also for establishments formerly a part of the "Chemicals, Not Elsewhere Classified" industry, which were engaged in the production of primary aluminum. The transfers of these industries and parts of industries were effective at

the 1939 census. Special tabulations were made in order that comparable figures for 1937 could be presented.

The principal metals or ores which form the basic materials used in these industries are copper, lead, zinc, tin, gold, silver, and aluminum. It should be noted, however, that these same basic metals are used to a large extent in certain industries assigned to other groups: for example, in the "Electrical Machinery" group and in industries of the "Machinery (Except Electrical)" group. A number of industries in Groups 14 and 20 also manufacture various commodities made wholly or partly from metals other than iron and steel.

Since the metals and alloys produced by the basic industries of Group 15 are used as materials by other industries in the group, the total cost of materials and the total value of products for the group as a whole include considerable amounts of duplication. (See "Duplication in cost of materials and value of products," p. 5.) The basic industries that extract the metals from the ore or refine or alloy them usually add relatively little to the value of the raw materials which they use, while the more highly elaborated manufacturing processes employed by the industries that use these metals and alloys as materials add very considerably to their value.

SUMMARY FOR GROUP 15.-NONFERROUS METALS AND THEIR PRODUCTS: 1939 AND 1937