residual air n.
See residual volume.
It cleanses the residual air, the air that remains in the lungs after each respiration; and it does much more.
What remains in the lungs, amounting to about 100 cubic inches, is called the residual air.
The residual air in the upper portions of the throat, mouth and nasal cavities is thrown into vibration.
The quantity that can under no circumstances be expelled (residual air) is about 100 cubic inches.