and entry head, and you should not permit loaders to enter a working face unless there has been a preliminary inspection made of the roof. Many foremen have done excellent work by managing the timbering so as to keep down the number of accidents from falls in their mines, but in the greater number of mines, as shown by inspection and by statistics gathered by the State inspectors, insufficient precautions are taken.

In steeply dipping coal beds there are added dangers from falls of roof or coal. A large fall at the face may knock out many props. Where accidents from this or similar causes have occurred frequently, you should try to see whether the method of mining is the safest that can be adopted; that is, if open rooms are run straight up the pitch, see whether inclined rooms may not be used, or whether the gob (goave) may not be filled by waste rock, or by washing in refuse or sand, as is done in some German mines in advancing work, and in mines of the anthracite fields of Pennsylvania in recovering pillars.

THE LAW IN PENNSYLVANIA.

The following extract from the mining law passed in Pennsylvania in 1911 is printed here to show the measures taken by the largest coal-mining State to compel miners and foremen to be careful and to watch the roof:

BITUMINOUS MINING LAW OF PENNSYLVANIA, IN FORCE 1911.

ARTICLE 25, RULE 1.-The miner shall examine his working place before beginning work, and take down all dangerous slate, or otherwise make it safe by properly timbering it, before commencing to mine or load coal. He shall examine his place to see whether the fire boss has left the date marks indicating his examination thereof, and if said marks can not be found it shall be the duty of the miner to notify the mine foreman or the assistant mine foreman of the fact. The miner shall at all times be careful to keep his working place in a safe condition during working hours.

Should he at any time find his place becoming dangerous from gas or roof or from any unusual condition that may arise, he shall at once cease working and inform the mine foreman or the assistant mine foreman of said danger, but before leaving his place he shall put some plain warning across the entrance thereto to warn others against entering into danger.

It shall be the duty of the miner to mine his coal properly before blasting and to set sprags under the coal while undermining, to secure it from falling. After each blast he shall exercise care in examining the roof and coal, and shall secure them safely before beginning to work.

He shall order all props, cap pieces, and all other timbers necessary at least one day in advance of needing them, as provided for in the rules of the mine. If he fails to receive said timbers, and finds his place unsafe, he shall vacate it until the necessary timbers are supplied.

ARTICLE 25, RULE 7.-All employees shall notify the mine foreman or the assistant mine foreman of the unsafe condition of any working place, hauling roads or traveling ways, or of damage to doors, brattices, or stoppings, or of obstructions in the air passages, when said conditions are known to them.

PUBLICATIONS ON MINE ACCIDENTS AND TESTS OF EXPLOSIVES.

The following Bureau of Mines publications may be obtained free. by applying to the Director, Bureau of Mines, Washington, D. C.: BULLETIN 10. The use of permissible explosives, by J. J. Rutledge and Clarence Hall. 1912. 34 pp., 5 pls.

BULLETIN 15. Investigations of explosives used in coal mines, by Clarence Hall, W. O. Snelling, and S. P. Howell, with a chapter on the natural gas used at Pittsburgh, by G. A. Burrell, and an introduction by C. E. Munroe. 1911. 197 pp., 7 pls.

BULLETIN 17. A primer on explosives for coal miners, by C. E. Munroe and Clarence Hall. 61 pp.. 10 pls. Reprint of United States Geological Survey

Bulletin 423.

BULLETIN 20. The explosibility of coal dust, by G. S. Rice, with chapters by J. C. W. Frazer, Axel Larsen, Frank Haas, and Carl Scholz. 204 pp., 14 pls. Reprint of United States Geological Survey Bulletin 425.

BULLETIN 26., Notes on explosive mine gases and dusts, by R. T. Chamberlin. 67 pp. Reprint of United States Geological Survey Bulletin 383.

BULLETIN 44. First national mine-safety demonstration, Pittsburgh, Pa., October 30 and 31, 1911, by H. M. Wilson and A. H. Fay, with a chapter on the explosion at the experimental mine, by G. S. Rice. 1912. 75 pp.. 7 pls.

BULLETIN 46. An investigation of explosion-proof motors, by H. H. Clark. 1912. 44 pp., 6 pls.

TECHNICAL PAPER 4. The electrical section of the Bureau of Mines, its purpose and equipment, by H. H. Clark. 1911. 12 pp.

TECHNICAL PAPER 6. The rate of burning of fuse as influenced by temperature and pressure, by W. O. Snelling and W. C. Cope. 1912. 28 pp.

TECHNICAL PAPER 7. Investigations of fuse and miners' squibs, by Clarence Hall and S. P. Howell. 1912. 19 pp.

TECHNICAL PAPER 11. The use of mice and birds for detecting carbon monoxide after mine fires and explosions, by G. A. Burrell. 1912. 15 pp.

TECHNICAL PAPER 12. The behavior of nitroglycerin when heated, by W. O. Snelling and C. G. Storm. 1912. 14 pp., 1 pl.

TECHNICAL PAPER 13. Gas analysis as an aid in fighting mine fires, by G. A. Burrell and F. M. Seibert. 1912. 16 pp.

TECHNICAL PAPER 17. The effect of stemming on the efficiency of explosives, by W. O. Snelling and Clarence Hall. 1912. 20 pp.

TECHNICAL PAPER 18. Magazines and thaw houses for explosives, by Clarence Hall and S. P. Howell. 1912. 34 pp., 1 pl.

TECHNICAL PAPER 19. The factor of safety in mine electrical installations, by H. H. Clark. 1912. 14 pp.

TECHNICAL PAPER 21. The prevention of mine explosions; report and recommendations, by Victor Watteyne, Carl Meissner, and Arthur Desborough. 12 pp. Reprint of United States Geological Survey Bulletin 369.

TECHNICAL PAPER 23. Ignition of gas by miniature electric lamps, by H. H. Clark. 1912. 5 pp.

TECHNICAL PAPER 24. Mine fires, a preliminary study, by G. S. Rice. 1912. 51 pp.

MINERS' CIRCULAR 2. Permissible explosives tested prior to January 1, 1911, and precautions to be taken in their use, by Clarence Hall. 1911. 12 pp. MINERS' CIRCULAR 3. Coal-dust explosions, by G. S. Rice. 1911. 22 pp. MINERS' CIRCULAR 4. The use and care of mine-rescue breathing apparatus, by J. W. Paul. 1911. 24 pp.

MINERS' CIRCULAR 5. Electrical accidents in mines; their causes and prevention, by H. H. Clark, W. D. Roberts, L. C. Ilsley, and H. F. Randolph. 1911. 10 pp., 3 pls.

MINERS' CIRCULAR 6. Permissible explosives tested prior to January 1, 1912, and precautions to be taken in their use, by Clarence Hall. 1912. 20 pp.