AIR VESSEL n.
A vessel, cell, duct, or tube containing or conducting air; as the air vessels of insects, birds, plants, etc.; the air vessel of a pump, engine, etc. For the latter, see Air chamber. The air vessels of insects are called tracheæ, of plants spiral vessels.
DEWAR VESSEL n.
A double-walled glass vessel for holding liquid air, etc., having the space between the walls exhausted so as to prevent conduction of heat, and sometimes having the glass silvered to prevent absorption of radiant heat; -- called also, according to the particular shape, Dewar bulb, Dewar tube, etc.