Abstract
Recently, it is often found that the regulating weight of the float of Dines' anemometer, changes gradually from its certificated value. To search for its cause, I have done experiments on the following two cases.
(1) The effect of the weight of water which condenses on the surface of the float above water level. I have confirmed that, about ten days after a Dines' anemometer was set up, 0.4 gramme of water has condensed on the surface of the float above water level. On the other hand, experiments showed that the water remaining on the surface of the float after being sprinkled on it amounted only to 2-3 grammes.
Accordingly, condensed water will not exceed 4 grammes on the outer and inner surfaces of the float above water level.
(2) The effect of water temperature on buoyancy.
I have experimented so that, for example, the regulating weight should increase about 8 grammes by water temperature descent from 28°C to 10°C.
Of the two causes, the latter is larger.
Thus, in reality, the regulating weight varies mainly owing to the above-mentiored two causes.
