| 摘要 |
The body (1) made of transparent plastic material has the shape of an elongate rectangle parallelepiped. In its longitudinal direction, the channel (2) goes through the body and opens out in the faces (3) and (4) of the body (1) delimiting openings (4) and (5). By introducing a predetermined quantity of water in the conduit held in vertical position and by orienting the opening (5) in the wind direction, it is possible to read the difference of level on the scale (6). |
