of such gases. Other investigations relate to the electric firing of shots and to other uses of electricity in mining operations.

The preliminary recommendations of the bureau in regard to regulations concerning the use of electricity in mines have been generally accepted by mining engineers and have been incorporated in the mining law of the largest mining State.

EXPLOSIVES USED IN COAI. MINES.

During the year a number of explosives have been thoroughly tested and have been designated as "permissible " explosives for use in dusty and gaseous mines under the conditions prescribed by the bureau. These "permissible" explosives give a short, quick, and relatively cool flame that is less likely to ignite inflammable gas or coal dust than is the flame of dynamite or that of black powder. Up to July 1, 1911, 88 explosives had passed the tests required by the bureau and had been placed on its list of permissible explosives.

In its endeavor to reduce the dangers attending the use of explosives in coal mining the bureau is meeting with the heartiest cooperation of manufacturers of explosives, who are steadily endeavoring to produce new explosives that will meet the increasingly rigid demands the bureau makes in behalf of safety. So many requests have been received for tests of these new explosives that the testing work is now nearly a year in arrears. But although the bureau is anxious to test these explosives promptly, in the belief that they may be superior to those already tested, it is unable to bring the work up to date without increasing the force of engineers and chemists engaged in making these tests, and the funds available for conducting the investigations are not sufficient to meet such increase. In testing and analyzing the explosives examined during the year nearly 10,000 tests, analyses, and determinations were made.

The chemical investigations, like the physical tests, of explosives have been carried on at the Pittsburgh station of the bureau. In addition to routine chemical analyses and tests, several improved methods of testing have been devised.

EXPERIMENTAL MINE.

The explosibility of a mixture of coal dust and air under test conditions having been repeatedly demonstrated at the experiment station of the bureau at Pittsburgh, Pa., the Bureau of Mines is now endeavoring to determine the exact conditions under which such explosions take place in mining operations. After having failed in many efforts to find a small coal mine available for its use, the bureau obtained a tract of coal land near Bruceton, Pa., about 10 miles south of Pittsburgh, and has opened there a small experimental mine for the study of coal-dust explosions. The plan of work does not contemplate the opening up of an ordinary coal mine, but rather the driving of a double entry, or tunnel, into the coal bed for about 2,000 feet and then opening, from the entries, a few rooms in which experiments may be conducted to determine, under the conditions of actual mining, the behavior of different types of explosives, the conditions 11355°-INT 1911-VOL 1-26

that determine the ignition of gas or dust, or mixtures of gas or dust and air, and the factors involved in the spread of the resulting explosions. The main purpose of the investigations carried on at the mine is, of course, to discover the most efficient methods of preventing such explosions. If the necessary funds can be obtained for carrying out this plan to the extent necessary for reliable results, the United States will have made an important contribution to the understanding and prevention of coal-dust explosions.

MINE-SAFETY CARS AND STATIONS.

Early in the investigation of mine disasters it was necessary to provide, in the important coal fields, facilities for enabling engineers to examine mines after disasters, while the mines were still full of poisonous explosive gases, in order that examination might be made while the evidences of a disaster were still fresh. It was found also that such prompt examinations would be useful in opening up these mines and in rescuing miners who might have been entombed. For the above reasons, there has been established in those of the larger coal fields in which mine disasters are most likely, mine-safety stations or mine-safety cars. The first of the stations was established at Urbana, Ill., in 1908; a second at Knoxville, Tenn., in 1909; and a third at Seattle, Wash. A fourth station at McAlester, Okla., and a fifth at Birmingham, Ala., were subsequently established, these with the Pittsburgh station making six stations suitably equipped.

Seven mine-safety cars are operated by the bureau. They were purchased as second-hand cars, refitted at a cost of about $1,500 each, and equipped at a cost of about $3,500 each. These cars are distributed as follows:

Distribution of the mine-safety cars operated by the Bureau of Mines.

Car No. 1, in the anthracite fields, with headquarters at Wilkes-Barre, Pa. Car No. 2, in the coal fields of New Mexico, Colorado, and Utah, with headquarters at Trinidad, Colo., and Salt Lake City, Utah.

Car No. 3, in the coal fields of western Kentucky, Indiana, and Illinois, with headquarters at Evansville, Ind.

Car No. 4, in the coal fields of Wyoming, Northern Colorado, and Utah, with headquarters at Rock Springs, Wyo.

Car No. 5, in the coal fields of Montana and Washington, with headquarters at Billings, Mont., and Seattle, Wash.

Car No. 6, in the coal fields of western Pennsylvania and northern West Virginia, with headquarters at Pittsburgh.

Car No. 7, in the coal fields of southern West Virginia, western Virginia, eastern Kentucky, and eastern Tennessee, with headquarters at Huntington, W. Va.

These cars do not remain at their headquarters, but each within its own district moves from one mining camp to another. When a serious mine disaster occurs in any district, the car in that district immediately drops its ordinary program and is carried to the scene of the disaster either by special locomotive or by the first available train. The men of the car, together with such local men as have had mine-rescue training, examine the mine as quickly as possible, penetrating the poisonous and explosive gases in it by means of the

breathing apparatus that they wear, and aiding in the rescue of any persons who may have been entombed in the mine. In case of a disaster in the coal fields near one of the six stations mentioned above, the miner in charge of this station, with all available rescue and first-aid equipment, proceeds by the first train to the scene of the disaster, and endeavors to accomplish, with the help of locally trained miners, the purposes mentioned above.

The primary purpose of the cars and stations is not the rescue work that they may accomplish, but the investigation of mine disasters. The incidental purposes are the development of more efficient mine'safety and first-aid equipment and methods, and the training of local miners at each of the mining camps visited, so that in case of mine accidents of any kind there will be at each mine men ready and equipped to render immediate and valuable assistance. To carry out these purposes the mining engineers of the bureau examine the safety conditions at mines, advise the mine officials as to the possibilities of improving these conditions, and deliver illustrated lectures to miners, calling their attention to the need of greater care in safeguarding their own lives and the lives of others. Daily demonstrations of mine-rescue and first-aid equipment and methods are given. Miners are trained in the practical methods of handling such equipment under mine-disaster conditions.

As illustrating the extent and importance of this work, attention may be called to the fact that there are more than 700,000 coal miners in the United States. A large majority of these are not from Englishspeaking countries and have come to this country unfamiliar with mining operations. The fact that more than 100,000 miners attended the lectures and demonstrations, and over 7,000 have received training in mine-rescue and first-aid work in less than one year, illustrates the progress toward safer mining. Permanent results are appearing in the establishment of a considerable number of local rescue and first-aid stations equipped by mining companies and manned by experienced local mining engineers competent to investigate mine conditions, conduct safety demonstrations, and to advise mine officials and miners as to methods for preventing mine accidents.

MINE-SAFETY LAWS AND REGULATIONS.

With a view to being able to point out the laws and regulations best adapted to prevent accidents in American mining, quarrying, and metallurgical industries, the bureau is bringing together the laws, rules, and regulations found to be now in force in other important mining countries. This work is now well under way. Copies not only of mining laws, but also of local and even of private mining rules and regulations, are being collected from different mining countries. As they are received they are carefully examined with a view to determining what provisions may be best adapted to diminishing mine accidents in the United States. This work involves a study not only of the laws as they exist in different countries, but of the important court decisions giving the proper interpretation of these laws and regulations.

PROGRESS OF INVESTIGATIONS.

FUEL INVESTIGATIONS.

INSPECTION OF GOVERNMENT FUEL PURCHASES.

The fuel-inspection division, with office and laboratory in Washington in the building occupied by the Bureau of Mines, is charged with collecting, analyzing, and testing samples of coal that represent deliveries under Government contracts providing for purchase on the specification basis. On such contracts the bidders guarantee the quality of the coal they offer in terms of ash, "dry coal," and British thermal units" as received," and the quality guaranteed by the successful bidder becomes the standard of his contract. The price paid the contractor is governed by the analysis of the coal he delivers.

The General Supply Committee (which issues specifications and proposals for the purchase of coal for the Federal buildings in the District of Columbia), the Quartermaster's Department of the Army, the navy yards and stations of the Navy Department, the Panama Railroad Co., the Isthmian Canal Commission, and other branches and institutions of the Federal service asked the Bureau of Mines for recommendations on the award of contracts.

To determine the award of a contract, particularly in the District of Columbia, it is frequently necessary for the Bureau of Mines to conduct a test in one or another of the Government power plants. It is also necessary in some cases for engineers of the bureau to visit the coal mines that are to supply the coal offered by the bidders and to take samples of coal for analysis and to collect information relating to the capacity of certain mines, or their ability to deliver to the Government coal shipments in accordance with the contract under consideration.

The engineers engaged in coal inspection sometimes have to visit Government power or heating plants, and give technical advice on the proper methods of burning a particular coal available at lowest cost at that point. For instance, during the year one of the engineers made a trip to Panama on a ship of the Panama Railroad Co., in order to ascertain the cause of reported difficulties in burning the coal in the ships' furnaces, and to discover remedies for the difficulties found to exist.

Something of the importance of this coal inspection and of the labor involved in it is indicated by the following figures:

During the year 8,230 samples of coal for analysis were received, representing 1,091,400 tons of coal, costing approximately $3,085,000, purchased for the Government under specifications. In the fiscal year 1909-10, 829,289 tons was purchased, costing approximately $2.287,000; and during the fiscal year 1911-12, probably 1,524,400 tons, costing approximately $4,809,000, will be bought by the Government on a specifications basis. These figures indicate the growth of the inspection work based on the wider adoption by the Government of the specification method of purchasing its fuel supplies. In addition to this, there are other purchases of coal by the Government based on the general preliminary investigations by the bureau, but not on specifications nor on exact delivery approvals, which now aggregate nearly $4,000,000 yearly. During the fiscal year 1910–11,

the laboratory made 19,411 moisture, 10,299 ash, 9,259 sulphur, 7,634 volatile-matter, and 9,964 calorimeter determinations; in all, 56,567 determinations.

The steaming tests that have been conducted and the advice given by the engineers of this section are resulting in economies to the Government. For instance, by a change in the kind of coal used one Government boiler plant is spending between $4,000 and $5,000 a year less than formerly for fuel; and another Government plant reduced its annual expense for fuel over $8,000. Other equally striking examples might be mentioned.

The specification method of purchase protects the Government against the delivery of poorer coal than that guaranteed by the contractor, and incites dealers to prepare the coal more carefully. When inferior coal is delivered, that is, coal below the contract standard, the contractors are penalized. In one instance, the analysis of samples by the bureau indicated the quality of the coal to be so far below the specified standard, that the resulting deductions in price amounted to about $25,000 in the settlements on the contract for a single year. Other instances might be cited.

The fuel-inspection division is divided into two sections, a coalsampling section and a laboratory section. The former supervises or assists in the sampling of all coal delivered to the Federal buildings in the District of Columbia, and gives directions concerning the sampling of coal delivered to Federal institutions outside of the District. The chemists of the laboratory analyze all samples received from the inspecting engineers, or from the custodians of Federal buildings in other parts of the country, and determine the heating value of the samples.

The fuel inspection is in local charge of G. S. Pope, engineer; P. M. Riefkin, and other assistant engineers who collect samples and make the field inspections; one clerk and two skilled laborers. The chemical analyses of these samples are made in the Washington laboratory by J. D. Davis, assistant chemist, aided by H. M. Cooper with two additional assistant chemists, seven junior chemists, one labora tory aid, one helper, and one laborer.

In addition to the engineers employed in the inspection and sampling of the coal purchased by the Government in the District of Columbia, one assistant engineer is stationed in New York and another in Norfolk for the sampling and inspection of coals shipped from those points for the Isthmian Canal Commission and the railway and steamships of the Panama Railroad Co.

A report setting forth the results of the purchase of coal on the specification basis by the Government during the fiscal year 1910 was prepared for publication.

STEAMING TESTS.

The work of this section during the year included special fuel-efficiency tests of coals offered for the Quartermaster General under the War Department, and for other branches of the Government service, all of which were made at the Pittsburgh station. Special steaming tests were made for the superintendent of the State, War, and Navy Building in the District of Columbia. In all there were made dur