Note 119 — AËRONAUTICS.
Reading edition
The artificial currents produced by the wing during its descent may be readily seen by partially filling a chamber with steam, smoke, or some impalpable white powder, and causing the wing to descend in its midst. By a little practice, the eye will not fail to detect the currents represented at d, e, f, g, h, i, l, m, o, p, q, r of fig. 129, p. 253.