CHAPTER XLIII.
CURIOSITIES OF VENTILATION.
Draughts and Drifts—Machinery of the Lower-Levels—Southward Currents—Use of Compressed Air—Industrious little Engines. 317
CURIOSITIES OF VENTILATION.
Draughts and Drifts—Machinery of the Lower-Levels—Southward Currents—Use of Compressed Air—Industrious little Engines. 317