A viscometer for liquids of low viscosity was built to be used at temperatures up to ca. 1000°C with the liquid maintained under a vacuum or inert gas atmosphere. The viscometer follows the method first suggested by Helmholz (8) and later successfully developed by Chiong and Andrade (4). In this method, the liquid is enclosed in a sphere; and the sphere is set in rotatory oscillation about a vertical axis. From measurements of the damping of the oscillations and the period and moment of inertia of the rotating pendulum, absolute values of the viscosity are calculated using the equations derived by Chiong and Andrade (4).
The effects of downward gravity wave reflection from atmospheric structure and horizontal winds; the geometry of the wave source and observation region; and the relative importance of the horizontal and vertical transport are being investigated for several different but often used gravity wave models. A quantitative study is also made on the relative importance of the purely gravitationally induced compression (G.I.C.) due to fluid particle altitude change and the actual wave compression which can occur at a fixed altitude in a gravity wave.