A circular dated November 19th, 1909, contains an outline of these
tests, which are to be conducted under the direction of Mr. J. W. Paul,
an experienced coal-mining engineer and ex-Chief of the Department of
State Mine Inspection of West Virginia. The lamps will be subjected to
the following tests:

(_a_).--Each lamp will be placed in a mixture of air and explosive
natural gas containing 6, 8, and 10% of gas, moving at a velocity of
from 200 to 2,500 ft. per min., to determine the velocity of the air
current which will ignite the mixture surrounding the lamp. The current
will be made to move against the lamp in a horizontal, vertical
ascending, and vertical descending direction, and at an angle of 45°,
ascending and descending.

(_b_).--After completing the tests herein described, the lamps will be
subjected to the tests described under (_a_), with the air and gas
mixture under pressure up to 6 in. of water column.

(_c_).--Under the conditions outlined in (_a_), coal dust will be
introduced into the current of air and gas to determine its effect, if
any, in inducing the ignition of the gas mixture.

(_d_).--Each lamp will be placed in a mixture of air and varying
percentages of explosive natural gas to determine the action of the gas
on the flame of the lamp.

(_e_).--Each lamp will be placed in a mixture of air and varying
percentages of carbonic acid gas to determine the action of the gas on
the flame.