tageously treated in copper furnaces as in lead works. Such ores would then have to be transported long distances. The result would be a serious reduction in the domestic output of gold and silver as well as a large reduction in the output of lead from domestic mines.

Refinery statistics from Engineering and Mining Journal includes lead smelted and refined from both domestic and foreign ore, except antimonial lead, and some lead derived from scrap and junk by smelters. 2 Lead contents of base bullion and lead in pigs, bars, etc. Some of this lead, therefore, appears again in the production of refined metal.

3 Wholly from foreign ore prior to 1914. Both domestic and foreign since 1914.

4 Not corrected to lead contents.

5 Also includes lead imported without payment of duty for treatment in bonded works for export.

Lead-Production and consumption of the world.

1 Data from U. S. Geol. Survey publications (from Metallgesellschaft) except as otherwise noted. 2 Calculated.

Engineering Mining Journal, Jan. 11, 1919.

This year is chosen, since it antedates the serious effects of political disturbances. Production in later years scarcely more than one-half this amount.

5 Included in "Other countries."

This total can be taken as the foreign-trade movement of the metal.

GENERAL INFORMATION.

PREFATORY NOTE.-This unit is presented as a digest of the purely tariff phases of the lead industry. A much more extended treatment of the subject, with greater emphasis on the important industrial phases, has been prepared for the auxiliary file and should be consulted for special features and additional information.

DESCRIPTION.

General.-Lead is the heaviest of the common metals. The market grades are (1) desilverized, (2) soft, and (3) antimonial lead. The terms used to distinguish between classes (1) and (2) are inexact, since the impurities that make lead hard have been removed from desilverized lead in the refining process. The term is retained to distinguish between metal derived from ores containing silver and that from ores that do not. Antimonial lead, an alloy of antimony and lead, is an entirely different product and has become important. more as a source of antimony than because of its lead content. It is treated in the tariff as "type metal" dutiable at 15 per cent on its lead contents (act of 1913) and is discussed in another unit of this series.

There are numerous minor market grades of lead such as corroding, chemical, hard, ordinary, etc., which vary slightly in properties and purity, but are not important from a tariff standpoint.

Tariff classification.-In the tariff classification of lead (Par. 153, act of 1913) the following products are grouped with the metal: Lead dross, lead bullion or base bullion, lead in pigs and bars, lead in any form not specially provided for in this section, old refuse lead run into blocks and bars, and old scrap lead fit only to be remanufactured."

Lead dross.--Dross is an oxidation product made in the smelting and refining processes. The most important type of lead dross is the skimming made in the softening furnace in the refining of base bullion. Lead dross generally contains at least 70 per cent of lead along with various impurities.

· Lead bullion (base bullion) is the name applied to lead carrying precious metals. It is a product of the blast furnace or other smelting furnace and differs from ordinary "soft" lead, a product made from the nonargentiferous ores of the Mississippi Valley, in that it must go through a refining operation for the recovery of the precious metal values and, incidentally, for the removal of harmful impurities. Base bullion frequently, although not invariably, contains some dross, but because of its gold and silver contents it is often more valuable than desilverized lead, although the latter is a much purer product.

Lead in blocks and pigs.-Both lead bullion and soft lead are cast in bars about 3 feet long and weighing from 80 to 110 pounds. In the case of bullion this is merely for convenience in handling and shipment. At some smelteries the lead bullion and dross are cast in the same mold; the dross rising to the top forms a bar a little wider than the lead bar. This classification in the tariff can be interpreted to include all merchantable forms of pig lead whether virgin (produced direct from the ore) or of secondary origin and whether soft, desilverized, or base bullion.

Secondary lead.-Old lead is recovered in various forms. Some of it is merely junk which may or may not be remelted in bars. Alloys containing lead are also salvaged and their metal content either separated or sold in the form of alloy pig.

See description of refining in auxiliary file. Details as to specific importations will be found in Treasury Decisions infra.

USES.

Minor

By far the largest consumption of lead is for the manufacture of white lead, which is used in paint. Large amounts of lead are used in the form of the metal as sheet, pipe, shot, and in alloys. uses are the production of lead wool, powdery lead, ribbon lead, and assay or "test" lead. The metal is also the source of litharge, red lead, orange mineral, and other lead pigments and fluxes used in paints and in glass and pottery manufacture. Chemical salts of lead are of some value in medicine, especially in the treatment of skin trouble.

The use of lead pipe for the water supply of dwelling houses is well known and it is also used extensively in chemical works. Sheet lead is used in very large quantities about chemical plants for lining tanks, acid chambers for sulphuric acid manufacture, and for various apparatus exposed to action of acids and other chemicals.

A most important war time use of lead is in shrapnel bullets in which it is alloyed with antimony. Somewhat similar alloys are used for type metal, in bearing metals, and for "hard-lead" castings. Solder, a mixture of lead with tin, is a very important outlet of the

metal.

SUBSTITUTES.

The principal use of lead is as a pigment. It has to meet the competition of zinc oxide and other zinc pigments and of barytes. Frequently all three are used in paint mixtures. Lead pigments made direct from the ore may also be considered as substitutes since they never take the form of market metal.

Sheet lead was formerly much used as flashing, roofing, and for other outside work on buildings, but has been largely displaced by zinc or galvanized iron sheets. The "leaded glass" used in windows is now generally supported by rolled zinc shapes rather than by lead.

DOMESTIC PRODUCTION.

The United States is the largest producer of lead as well as the largest consumer of the metal in the world. In addition to smelting its own ores, it carries on a large smelting and refining business, treating by far the greater part of the Mexican output. In 1918 the domestic refineries reported the production of a little more than 550,000 tons of lead from domestic ore and 109,159 tons from foreign ore, a total output of all kinds of lead amounting to 659,888 tons and valued at the average quotation of the year at more than $97,000,000. The 1917 output was 635,669 tons worth, at the average New York price, about $112,000,000.

Raw materials.-Lead ores are, of course, the primary source of metallic lead. By-products that are also treated in smelteries and which furnish lead were originally derived from ore. At many

The latest available data as to domestic consumption are for 1909. Statistics for that year, purporting to cover over 90 per cent of the consumption, are given by the Engineering and Mining Journal as follows: White lead and oxides, 38 per cent; pipe, 15.2 per cent; Sheets, 6.7 per cent; shot, 10.4 per cent; and other purposes, 29.7 per cent of the total. Later years will show much the same relative consumption, except for the increased munition proportion during war.

Engineering and Mining Journal data. These figures include lead derived from scrap and junk by smelters whose main business is treating ore. They are, therefore, slightly in excess of those reported by the Geological Survey (p. 32) as the latter are for virgin lead only.

smelteries, however, the treatment of gold and silver ores-often containing little or no lead-is an important feature of the business. A certain amount of flux is needed with almost any ore in order to convert the waste material into an easy melting slag. One of the most important considerations in the smelting business is to so adjust the ore supply as to require the minimum of barren material. The economy of adding flux in the form of ores of lead, copper, or precious metals instead of in the form of material valuable only for its fluxing properties is evident.

Coke is the fuel necessary for the furnace operation. The substitution, in part, of powdered coal, introduced with the air blast, is a procedure now under experiment, which may mean an important fuel economy.

Equipment.-Practically all the machinery and equipment of domestic lead smelteries is of American design and construction. American smelters, therefore, are on at least an equal footing with those of any country. The costs of grading, erection of buildings, furnaces, etc., are slightly greater in this country than in certain other countries because of the higher wage scale.

Methods of production.-Lead is recovered from its ores by a smelting process. For the typical sulphide ore, the smeltery treatment consists of roasting, followed by fusion with coke in a blast furnace. The blast furnace makes metallic lead waste slag, and leady byproducts that must be retreated. The furnace lead (bullion) containsall the recoverable precious metals that were present in the furnace charge. These values are recovered by a separate process, called desilverizing or refining, either at the smeltery or at another plant. Refining also removes base metal impurities, hence a small part of the Missouri soft lead (much of which is produced by a less elaborate smelting operation) is desilverized in spite of the fact that the small amount of silver recovered pays only a fraction of the cost of the operation. All foreign lead, however, may be classed as argentiferous. A brief outline of the more important processes for the recovery of lead metal from its ores with remarks as to the economic phases of the art has been prepared for the auxiliary file. The outstanding features are that the operation requires heavy and expensive equipment, a large force of common labor, and many skilled laborers under skilled technical supervision. In the United States this has led to a more extensive installation of machinery than in foreign smelteries having a cheaper supply of common labor.

Female and child labor are not factors in this industry. In spite of the poisonous character of lead compounds, lead smelting is not an unusually dangerous or unhealthful occupation.

Organization. The strength of the American Smelting & Refining Co. is apparent. This organization, frequently referred to as the "Smelter Trust," controls about one-half the lead-producing capacity of the United States. Its control of the industry is less pronounced now, however, than it was in 1907, when it was the only large smelter of silver-lead ores in the United States and, in addition, controlled a large fraction of the soft-lead output from Missouri.

This corporation was the first to introduce horizontal combination on a large scale in the lead smelting industry. After gaining control

of existing plants (1901 to 1906), it adopted a vigorous policy of centralization of its operations. American lead smelteries are now located, almost without exception, at transportation centers adapted for the focusing of ore and supplies. Proximity to one large specific source of ore is no longer the controlling factor in the location of smelting works. Ores, coke, and other supplies must be drawn from many localities and often from considerable distances. Labor supply is also a factor in centralization.

While the American Smelting & Refining Co. was quite successful in gaining control of smelting plants, it was less successful in gaining control of the ore supply. An industrial monopoly involves control of the raw material. In lead production, the raw material is the -ore. Works can be duplicated and the art of smelting the common metals is general knowledge, so that metallurgical skill and experience can be bought. But valuable mines are few. While the American Smelting & Refining Co. fully recognized the principle, as evidenced by the organization of an exploration company, it was unable to secure a sufficient number of valuable mines to absolutely dominate the ore situation.

The inherent strength of vertical combinations is well illustrated in southeast Missouri, where consolidation and integration of interests began prior to the advent of the American Smelting & Refining Co. When the latter entered this field it was unable to secure any of the operating properties. It did, however, gain control of undeveloped properties, built a large smeltery at Federal, Ill., and soon became one of the large producers of that region.

The ownership of mines also resulted in the building of a large lead smeltery at Midvale, Utah (U. S. Smelting, Refining & Mining Co.) and a large lead plant in connection with the copper works of the International Smelting Co. (Anaconda Copper Co. interests) at Tooele, Utah. In the Idaho field also two of the largest producers have built their own smelting works.

Capitalization. According to the census compilation the total capital invested in lead smelting and refining in 1914 was $143,249,000, distributed among 22 establishments, only one of which was not under corporate control. All but three of these establishments had an annual output of at least $1,000,000 annually. An interesting feature is that the number of establishments in 1909 was 28 and the number of wage earners was 7.424 as compared with 7,385 in the later year, although the value of the output was only $167,406,000 as compared with $171,579,000 in 1914. These, statistics, therefore, confirm the tendency toward concentration.

It is difficult to ascertain the present investment in lead smelting operations on account of the varied activities of the different smelting companies. The American Smelting & Refining Co. is one of the largest producers of copper and other metals as well as lead, and practically all of the other producers sell a number of by-products. Another difficulty is the amalgamation of mining interests and, to a much less degree, consuming interests in the same corporation.

Geographical distribution.-Statistics as to the production of its individual plants are not disclosed by the American Smelting &

These figures of output include the value of copper, silver, gold, and chemicals as well as the value of the lead produced. The latter, according to the reports of the Geological Survey, was valued at $42,285,000 in 1914 and $38,434,000 in 1909,