Manganese does not occur as a native metal, but is found in nature in a great variety of combinations with other elements, whereby it forms a part of more than 100 minerals. Practically all of the manganese of commerce, however, is obtained from one or more of the first seven of the following minerals: Psilomelane, Rhodochrosite, Pyrolusite, Bementite, Manganite, Rhodonite, Wad, Hausmannite, Braunite, and Alabandite. 104 p.

The name asbestos is derived from the Greek word for inextinguishable or indestructible, and the adjective asbestiform. is applied to any mineral that is readily separable into more or less flexible fibers. Among the more important asbestiform minerals, from the standpoint of toughness, incombustibility, and low heat conductivity, the following are included under the general trade name of asbestos: Chrysotile (serpentine asbestos), amphibole asbestos (including fibrous varieties of tremolite, actinolite, etc.), anthophyllite asbestos, crocidolite (Cape blue asbestos), and amosite. Unless stated otherwise, however, the term "asbestos" usually means chrysotile. It is the only variety of asbestos known to occur in commercial quantities in Arizona. 97 p.

From the time the Arizona Bureau of Mines was created it has been flooded with requests for a bulletin that would give a fairly accurate idea of the importance and magnitude of the mineral industries in the State, but nothing purporting to cover this subject has been written for many years, and the desired information was scattered through scores of books, bulletins, and magazine articles. When Mr. J. B. Tenney was added to the staff of the Bureau as Assistant Geologist, two tasks were specifically allotted to him: First, and most important, he was made responsible for the preparation of an annual report upon the mineral industries of the State together with much briefer quarterly progress reports on the same subject. His second responsibility was the preparation of a history of mining in Arizona for which a strong demand existed. This volume constitutes the first annual report issued by the Bureau. It was written almost entirely by Mr. Tenney, although Dr. E. P. Mathewson obtained and arranged much of the data relating to smelters and mills. Subsequent issues will doubtless differ materially from the first, since the detailed data contained therein will not be repeated, and only changes in practice or personnel and new developments will be mentioned. Furthermore, it is hoped and planned to make subsequent annual reports more statistical, and to discuss generally the condition and probable future of the mineral industries in various parts of the State. 135 p.

Many people feel the lure of gold, and dream of finding great nuggets of the gleaming yellow metal. The wonderful thrill of such a discovery must, however, be experienced vicariously, if at all, by most of us. Tales of hardship followed by the acquirement of a fortune in golden dust and nuggets fascinate us even though we know that they are only fiction. How much stronger, then, must be the appeal of true accounts of such achievements. It is probably because of the almost universal interest in the subject that the first edition of this bulletin was so soon exhausted, and not because people in every state in the Union, who requested copies, desired data on the mineral resources of Arizona. At any rate, this bulletin has been the most popular one issued by the Bureau. 60 p.

In view of the lack of petroleum production in the State of Arizona and the probability of its occurrence, the State Bureau of Mines is to publish a series of bulletins, of which this is the first. It is hoped this series will give the fundamental principles of the origin, geological occurrence, physical and chemical properties of petroleum and natural gas. 32 p.

In 1923 the attention of engineers was first directed to the Emmet Mercury Boiler, and much interest was aroused by the statement that tests conducted at Hartford, Conn., had demonstrated that the substitution of mercury for water resulted in a saving of nearly 50 per cent in fuel. Since the Hartford installation required 30,000 pounds of mercury and the production of the entire world for the preceding fifteen years had hardly been sufficient to supply half of the high pressure boilers in the United States alone, it seemed possible that the demand for mercury might be suddenly increased and that the price might advance. Consequently, officials of the United States Bureau of Mines endeavored to collect data relating to potential undeveloped sources of mercury in this country, and the Director of the Bureau attempted to obtain, through E. D. Gardner, Superintendent of the Southwestern Experiment Station of the Bureau, information concerning the mercury resources of Arizona. A consultation with the writer brought out the fact that, although mercury ore was known to exist at several places in the State, and a small quantity of the metal had been produced, reliable data bearing on the extent and commercial value of the deposits were not available. 112 p.

The bringing of the work of the State Bureau of Mines directly to the people of the State in their home towns is to be an important feature of the work of the Bureau during the next year. Regular tours of lectures will be given, one or more members of the staff being ecntinuously in the field. In the center of this pamphlet will be found the details of the regular course of lectures, giving the dates, the names of the towns and the lecturers. In addition to this the Bureau of Mines will be pleased to furnish special lectures for any occasion as far as its funds and the time of the men are available. 10 p.

The fact that base metals have been quoted at relatively low prices since the war has caused many Arizona prospectors to lose interest in them and to turn their attention to rare metals. Judging from the number of inquiries concerning uranium-radium minerals that reach the Arizona Bureau of Mines, it seems evident that they are being eagerly sought and that information concerning them is in demand. This booklet has been prepared to supply such data concerning uranium and radium as prospectors and miners may find useful and is admittedly nothing but a compilation of the more important known facts concerning these metals and their ores. 26 p.

This booklet has been prepared to meet the demand for and to take the place of Bulletins No. 65, Oil and Its Geology, and No. 69, Prospecting for Petroleum, issued by the Arizona Bureau of Mines four years ago, which have been out of stock nearly two years. Both bulletins were written by the junior author of this publication. While portions of the two old bulletins have been incorporated into this work, most of Part I has been abstracted with some modifications from an address delivered by the senior author on May 29, 1919, at El Paso. Texas, which was later published in the Arizona Mining Journal. No attempt has been made to write a manual for petroleum geologists; in fact, the end sought was merely to impress the general public with the fact that the accumulation and distribution of petroleum are governed by certain fairly well understood, but generally unknown or unappreciated, laws which only a welltrained and experienced geologist can satisfactorily apply. It was, therefore, deemed unnecessary and even undesirable to go into details or to discuss exceptions to and deviations from the general statements made. The reader who wishes to know "the whole story" is directed to the books on petroleum listed in the Bibliography. 45 p.

The Arizona Bureau of Mines has received so many requests for information about vanadium and Arizona deposits of ores of this metal that the stock of Bulletin No. 18, Vanadium, has been exhausted. In preparing this revision of the bulletin issued in 1916, that work has been completely rewritten and, so far as possible, brought up to date. The bulletin herewith offered is admittedly nothing but a compilation of facts already published, and no attempt has been made to make it an exhaustive treatise on the subject of vanadium. It is believed, however, that the data ordinarily sought by prospectors are herein presented, and it is hoped that the dissemination of this in formation will stimulate vanadium mining in Arizona. 23 p.