_Swamp._ A depression in the seam. _Synclinal._ A fold of strata in which the inclination of the sides is from the axis upward. _Tipple._ In the bituminous regions, a building in which coal is dumped, screened, and loaded into boats or cars. _Trapper._ See Door boy. _Traveling way._ A passageway for men and mules in or into the mines. _Trip._ The number of cars less than enough to constitute a train drawn at one time by any motive power. _Tunnel._ An opening into a mine driven horizontally across the measures. _Under-clay._ See Fire clay. _Underholing._ See Bearing in. _Upcast._ An opening from a mine through which air is taken out. _Vein._ Used (improperly) synonymously with seam, bed, or stratum. _Wagon._ A mine car. _Waste._ Gob; coal dirt. _Water level._ An entrance into or passage in a mine, driven with just sufficient grade to carry off water. _White damp._ Carbonic oxide. _Wings._ See Keeps. _Work._ To mine. _Working face._ A face at which mining is being done. _Workings._ The excavations of a mine, taken as a whole; or, more particularly, that portion of the mine in which mining is being done. INDEX. Accidents resulting from falls, 126; to boys, 218. Act of 1885, 88. After damp, composition of, etc., 167. Air currents in mines, 148, 149. Air, deterioration of, in mines, 147, 152. Airways, beginning of, 95. Allen, Nicholas, 49, 62. Ancients, use of coal by, 35. Animal life of Carboniferous era, 18. Anthracite coal, analysis of, 6; commercial sizes of, 181; description of, 8; ignition of, 59; of bituminous origin, 25; skill in mining, 192. Anticlinals, 25. Appalachian Range, 3. Archean time, 3. Areas of coal measures, 31; of Pennsylvania coal fields, 33, 34. Avondale Mine, disaster at, 173. Baltimore vein, 75. Basin in a coal seam, 29. Battery in steep chambers, 108. Bearing in, in bituminous mines, 197. Benches in coal seams, 23–115. Bituminous coal, analysis of, 7; description of, 8; process of mining, 194. Black damp, composition, etc., 169. Blasting in mines, 119, 120, 125, 131. Blossom of coal, 77. Blower of gas, 160. Boys, accidents to, 218; amusements of, 219; at tipple work, 202; characteristics of, 217; duties of, at breaker, 215; in British coal mines, 205. Boy door-tenders, duties of, 214. Boy drivers, duties of, 210. Braddock’s road, 40. Brattice at face of chamber, 103. Breaker, description of, 179; location of, 178, 183; passage of coal through, 185; picking shutes in, 186; structure and appearance of, 184. Break through, in bituminous mines, 195. Breast. See Chamber. Bryden, Alexander, 143. Bryden, Andrew, 140, 168. Buildings at mouth of shaft, 176. Buntons in shaft, 89. Butler, Col. Lord, 56.