far exceeds that of any other single concern in the United States, that
the results cannot but be of great value to all engineers and to all
those engaged in engineering works.


MINE ACCIDENTS INVESTIGATIONS.

_Organization, and Character of the Work._--The mine rescue
investigations, carried on at the Federal testing station, at Pittsburg,
Pa., include five lines of attack:

1.--Investigations in the mines to determine the conditions leading up
to mine disasters, the presence and the relative explosibility of mine
gas and coal dust, and mine fires and means of preventing and combating
them.

2.--Tests to determine the relative safety, or otherwise, of the various
explosives used in coal mining, when ignited in the presence of
explosible mixtures of natural gas and air, or coal dust, or of both.

3.--Tests to determine the conditions under which electric equipment is
safe in coal-mining operations.

4.--Tests to determine the safety of various types of mine lights in the
presence of inflammable gas, and their accuracy in detecting small
percentages of mine gas.

5.--Tests of the various artificial breathing apparatus, and the
training of miners and of skilled mining engineers in rescue methods.