CHAPTER XIX.
CARBONIC ACID GAS.
Q. What is choke damp?
A. Carbonic acid gas accumulated at the bottom of wells and pits, which renders them noxious, and often fatal.
Q. Why is not this carbonic acid taken up by the air, and diffused, as it is in cities?
A. Because (being heavier than common air) it cannot rise from the well or pit; and no wind can get to it to blow it away.
Q. Is carbonic acid wholesome?
A. No; it is fatal to animal life, when inhaled through the mouth; acting on the stomach, as a narcotic poison (i. e.. a poison which produces death from drowsiness).
Q. How can any one know, if a place be infested with carbonic acid gas?