[AIR- 7.]
1. Nat. Hist. Any vessel whose function is to contain air; especially, the tracheæ or respiratory tubes of insects, and the spiral vessels in plants.
1676. Grew, Anat. Plants, II. iii. (1682), 70. The Lignous Part is also Compounded of Two kinds of Bodies scil. succiferous or Lignous and Aer-Vessels.
1692. Ray, Creation, I. (1722), 72. Insects … having more Air-vessels for their Bulk by far than they [Animals].
1753. Chambers, Cycl. Supp., Air-vessels are found in the leaves of all plants.
1819. Pantologia, s.v., Air-vessels are distinguished from sap-vessels.
2. Hydraulics; = AIR-CHAMBER.
1819. Pantologia, s.v., Air-vessels … metalline cylinders placed between the two forcing-pumps in the improved fire-engine.
c. 1850. Nat. Phil. (S. S. B. A.), 90. The fire-engine consists of two forcing-pumps, both communicating with an air-vessel.
