Title: An Elementary Class-book of Practical Coal-mining
Description: Book digitized by Google from the library of the University of California and uploaded to the Internet Archive by user tpb.
Subjects: coal, pressure, feet, shaft, inches, rope, weight, seams, air, seam, square inch, cubic foot, compressed air, total pressure, winding engines, carbonic acid, square foot, tail rope, full corves, winding engine