PREFACE.

This is one of a series of Tariff Information Surveys prepared by the United States Tariff Commission and transmitted to the. Committee on Ways and Means. The series covers all of the articles and commodities provided for in the tariff act of October 3, 1913, and others not specifically provided for. It is arranged in the numerical order of paragraphs of that act.

In some cases two or more paragraphs have been combined in one pamphlet. In doing this, industrial relationship of the articles has been followed when possible. In those instances where a paragraph has been treated under a preceding paragraph of the tariff act, reference is made to this fact at the point where the paragraph appears in numerical order. Where one grade of an article is dutiable and another grade of the same article is on the free list, the article is discussed under the dutiable paragraph which appears first in numerical order in the tariff act. In certain instances articles of close industrial relationship and which occur in separate paragraphs of the tariff act have been combined under one paragraph for convenience of discussion. Reference is made to this fact at the point where the commodities would naturally occur in numerical order. The first pamphlet in the series is an "Introduction and Index," which contains:

1. An introductory chapter discussing the scope of the series and the general method of treatment.

2. An alphabetical index of the articles provided for in the tariff act of 1913, showing the paragraph of the act in which the article is provided for and, if discussed under a different paragraph, the number of such paragraph.

3. A list of the pamphlets in the series, showing the paragraphs and articles included in each pamphlet.

Thus by use of this "Introduction and Index," the exact location of the discussion relating to a given article or commodity can be ascertained.

In the preparation of this report the Tariff Commission had the services of Dr. Grinnell Jones and Sidney D. Kirkpatrick of the Chemical Division of the Commission's staff, and of others.

THE INCANDESCENT GAS-MANTLE INDUSTRY.

SUMMARY.

The articles considered in this report are monazite sand, thorite, thorianite, cerite, thorium nitrate, cerium nitrate, incandescent gas mantles, cerium metal, pyrophoric alloy, and the radioactive substitute, mesothorium. These commodities are classified in the tariff act of 1913 under the following paragraphs:

5. "Alkalies, alkaloids, and all chemical and medicinal compounds, preparations, mixtures and salts, and combinations thereof not specially provided for in this section, 15 per centum ad valorem." (Cerium nitrate and other cerium salts are included hereunder.)

154. "Metallic mineral substances in a crude state, and metals unwrought, whether capable of being wrought or not, not specially provided for in this section, 10 per centum ad valorem; monazite sand and thorite; thorium, oxide of and salts of; gas, kerosene, or alcohol mantles treated with chemicals or metallic oxides, 25 per centum ad valorem; and gas-mantle scrap consisting in chief value of metallic oxides, 10 per centum ad valorem." (Pyrophoric alloy, if imported in ingots, has been classified as a metal unwrought.)

167. "Articles or wares not specially provided for in this section, if composed wholly or in part of platinum, gold, or silver, and articles or wares plated with gold or silver, and whether partly or wholly manufactured, 50 per centum ad valorem; if composed wholly or in chief value of iron, steel, lead, copper, brass, nickel, pewter, zinc, aluminum, or other metal, but not plated with gold or silver, and whether partly or wholly manufactured, 20 per centum ad valorem." (Pyrophoric alloy, if in sizes suitable for use, has been classified hereunder at 20 per cent.)

445. (Free List.) "Cerium, cerite, or cerium ore.'

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585. (Free List.) * * * radioactive substitutes * * *" (Mesothorium is included hereunder.)

The most important of these commodities is the incandescent gas mantle, which is composed of 99 per cent of thoria and 1 per cent of ceria. Its fundamental raw material is the mineral known as monazite sand, from which pure thorium nitrate and cerium nitrate are obtained by complex chemical processes. A fiber is knit into the proper form for the mantle and then soaked in a solution of thorium and cerium nitrates. After drying it is heated to a white heat in order to burn off the fabric and to convert the nitrates into oxides, which retain the shape and structure of the original fabric. The incandescent gas mantle gives the cheapest illumination wherever natural or manufactured gas is available. The world's consumption of gas mantles may be estimated at 300 million per year, and of this number at least 80 million are annually used in the United States. The domestic industry is well developed and a considerable export business has been established.

Monazite sand is of wide occurrence, but the only deposits which have ever been worked commercially are in Brazil, India, and in North and South Carolina. The American industry, however, has made little or no progress since 1906, principally because the deposits are low-grade, small and scattered, and can not be worked in competition with the richer and more easily mined deposits of India and Brazil. The world's annual consumption of monazite sand is approximately 3,500 tons.