| 摘要 |
<p>The device comprises a transparent cylinder (1) with an identical closure cap (6,11) at either end, filled with a liquid. A sinking body (3) is contained within the cylinder (1) and slowly descends through the liquid after the inversion of the cylinder (1). The sinking body (3) comprises a disc with a slightly lesser dia. than the inner dia. of the cylinder (1) and with two identical opposing concave surfaces. A number of holes (4) are provided through the disc, spaced around its centre, for passage of the liquid as it descends through the cylinder (1). Pref. the latter is made of glass or plastics while the two end caps (6,11) are made of brass each with a lipped edge (7,12) to provide an enlarged support surface. At least one end cap (6) includes an overflow valve (9). The device can be used to time a telephone call.</p> |
