Conversation on Mines

ABEL HEYWOOD acid gas adopted air-gates atmospheric weight better black-damp blocks of coal breadth carbonic acid carbonic acid gas cause cold air Conversations on Mines cubic feet cubic foot current of air dial diameter diminished distinct currents division down-cast explosive gas Father feet area feet of air figure fixed flame friction furnace gases give group of miners Hetton Colliery Hopton impure air inches inches of mercury knowledge of mines length loss Lund-hill managers mines?-Father mixture mode of ventilation multiply natural heat needle nitrogen North Seaton Colliery number of bricks object oxygen parallel ruler person pillars pressure produced propel protracter pure air quantity of air quantity of gas reduced road roof rush safety lamp separate sexagesimal sight splitting steam strata Suppose surface takes place temperature theodolite third sight tram-gates tram-roads underground up-cast shaft velocity ventilating mines whole coal wind yards