Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 | Page 4

investigations.
Meantime, in anticipation of the appropriation, Mr. Clarence Hall, an
engineer experienced in the manufacture and use of explosives, was
sent to Europe to study the methods of testing explosives practiced at
the Government stations in Great Britain, Germany, Belgium, and
France. Mr. Joseph A. Holmes also visited Europe for the purpose of
studying methods of ameliorating conditions in the mines. Three
foreign mining experts, the chiefs of investigating bureaus in Belgium,
Germany, and England, spent three months studying conditions in the
United States at the invitation of the Secretary of the Interior, to whom
they submitted a valuable report.[5]
Under the supervision of the writer, Chief Engineer of these
investigations, detailed plans and specifications had been prepared in
advance for the necessary apparatus and the transformation of the

buildings at Pittsburg to the purposes of this work. It was possible,
therefore, to undertake immediately the changes in existing buildings,
the erection of new buildings, the installation of railway tracks,
laboratories, and the plumbing, heating, and lighting plant, etc. This
work was carried on with unusual expedition, under the direction of the
Assistant Chief Engineer, Mr. James C. Roberts, and was completed
within a few months, by which time most of the apparatus was
delivered and installed.
One building (No. 17) is devoted to the smaller physical tests of
explosives. It was rendered fire resistant by heavily covering the floors,
ceiling, and walls with cement on metal lath, and otherwise protecting
the openings. In it are installed apparatus for determining calorific
value of explosives, pressure produced on ignition, susceptibility to
ignition when dropped, rate of detonation, length and duration of flame,
and kindred factors. Elsewhere on the grounds is a gallery of
boiler-steel plate, 100 ft. long and more than 6 ft. in diameter, solidly
attached to a mass of concrete at one end, in which is embedded a
cannon from which to discharge the explosive under test, and open at
the other end, and otherwise so constructed as to simulate a small
section of a mine gallery (Fig. 2, Plate VI). The heavy mortar
pendulum, for the pendulum test for determining the force produced by
an explosive, is near by, as is also an armored pit in which large
quantities of explosive may be detonated, with a view to studying the
effects of magazine explosions, and for testing as to the rate at which
ignition of an explosive travels from one end to the other of a cartridge,
and the sensitiveness of one cartridge to explosion by discharge of
another near by.
[Illustration: PLATE VI.
Fig. 1.--Explosion from Coal Dust in Gas and Dust Gallery No. 1.
Fig. 2.--Mine Gallery No. 1.
Fig. 3.--Ballistic Pendulum.]
In another building (No. 21), is a well-equipped chemical laboratory for

chemical analyses and investigations of explosives, structural materials,
and fuels.
Several months were required to calibrate the various apparatus, and to
make analyses of the available natural gas to determine the correct
method of proportioning it with air, so as to produce exact mixtures of
2, 4, 6, or 8% of methane with air. Tests of existing explosives were
made in air and in inflammable mixtures of air and gas, with a view to
fixing on some standard explosive as a basis of comparison. Ultimately,
40% nitro-glycerine dynamite was adopted as the standard.
Investigative tests having been made, and the various factors
concerning all the explosives on the market having been determined, a
circular was sent to all manufacturers of explosives in the United States,
on January 9th, 1909, and was also published in the various technical
journals, through the associated press, and otherwise.
On May 15th, 1909, all the explosives which had been offered for test,
as permissible, having been tested, the first list of permissible
explosives was issued, as given in the following circular:
"EXPLOSIVES CIRCULAR NO. 1. "DEPARTMENT OF THE
INTERIOR. "United States Geological Survey. "May 15, 1909.
"LIST OF PERMISSIBLE EXPLOSIVES. "Tested prior to May 15,
1909.
"As a part of the investigation of mine explosions authorized by
Congress in May, 1908, it was decided by the Secretary of the Interior
that a careful examination should be made of the various explosives
used in mining operations, with a view to determining the extent to
which the use of such explosives might be responsible for the
occurrence of these disasters.
"The preliminary investigation showed the necessity of subjecting to
rigid tests all explosives intended for use in mines where either gas or
dry inflammable dust is present in quantity or under conditions which
are indicative of danger.

"With this in view, a letter was sent by the Director of the United States
Geological Survey on January 9, 1909, to the manufacturers of
explosives in the United States, setting forth the conditions under
which these explosives would be examined and the nature of