(1):

(v. t.) To breathe out. Hence: To emit, as vapor; to send out, as an odor; to evaporate; as, the earth exhales vapor; marshes exhale noxious effluvia.

(2):

(v. t.) To draw out; to cause to be emitted in vapor; as, the sum exhales the moisture of the earth.

(3):

(v. i.) To rise or be given off, as vapor; to pass off, or vanish.