Q. Is all the nitrogen rejected by the lungs?
A. Yes; all the nitrogen of the air is always exhaled.
Q. What is carbonic acid gas?
A. As carbon has a very great affinity for oxygen, therefore, whenever they are exposed to heat, they combine, and form carbonic acid gas (or what is vulgarly called fixed air).
Q. Is carbonic acid gas wholesome?
A. No; it is quite fatal to animal life; and whenever it is inhaled, it acts like a narcotic poison, (producing drowsiness which ends in death).
Q. Why is a crowded room unwholesome?
A. Because the oxygen of the air is either absorbed by the lungs, or substituted for carbonic acid gas, which is a noxious poison.
Q. Mention the historical circumstances, so well known in connection with the “Black Hole of Calcutta.”
A. In the reign of George II, the Raja (or Prince) of Bengal[12] marched suddenly to Calcutta to drive the English from the country; as the attack was unexpected, the English were obliged to submit, and 146 persons were taken prisoners.