(_f_).--Lamps equipped with internal igniters will be placed in explosive mixtures of air and gas in a quiet state and in a moving current, and the effect of the igniter on the surrounding mixture will be observed. (_g_).--The oils (illuminants) used in the lamps will be tested as to viscosity, gravity, flashing point, congealing point, and composition. (_h_).--Safety-lamp globes will be tested by placing each globe in position in the lamp and allowing the flame to impinge against the globe for 3 min. after the lamp has been burning with a full flame for 10 min., to determine whether the globe will break. (_i_).--Each safety-lamp globe will be mounted in a lighted lamp with up-feed, and placed for 5 min. in an explosive mixture of air and gas moving at the rate of 1,000 ft. per min., to determine whether the heat will break the glass and, if it is broken, to note the character of the fracture. (_j_).--Safety-lamp globes will be broken by impact, by allowing each globe to fall and strike, horizontally, on a block of seasoned white oak, the distance of fall being recorded. (_k_).--Each safety lamp globe will be mounted in a safety lamp and, when the lamp is in a horizontal position, a steel pick weighing 100 grammes will be permitted to fall a sufficient distance to break the globe by striking its center, the distance of the fall to be recorded. (_l_).--To determine the candle power of safety lamps, a photometer equipped with a standardized lamp will be used. The candle-power will be determined along a line at right angles to the axis of the flame; also along lines at angles to the axis of the flame both above and below the horizontal. The candle-power will be read after the lamp has been burning 20 min. (_m_).--The time a safety lamp will continue to burn with a full charge of illuminant will be determined. (_n_).--Wicks in lamps must be of sufficient length to be at all times in contact with the bottom of the vessel in which the illuminant is contained, and, before it is used, the wick shall be dried to remove moisture. _Mine-Rescue Methods._--Mr. Paul, who has had perhaps as wide an experience as any mining man in the investigation of and in rescue work at mine disasters, is also in charge of the mine-rescue apparatus and training for the Geological Survey. These operations consist chiefly of a thorough test of the various artificial breathing apparatus, or so-called oxygen helmets. Most of these are of European make and find favor in Great Britain, Belgium, France, or Germany, largely according as they are of domestic design and manufacture. As yet nothing has been produced in the United States which fulfills all the requirements of a thoroughly efficient and safe breathing apparatus for use in mine disasters.