both the duration and intensity of dewfall. Dew duration recorders operate to afar extent in the'same way as the above mentioned wetness recorders. For quantitative assssments, dew balances are used to weight the amount of moisture deposited on a surface with similar structure as leaves. The amount of dew on natural leaves can be measured by collecting it with blotting paper which is weighed while dry and after being pressed against the leaf. The leaf surface has, however, to be measured as well. 2.5 Mind. 2.5.1 General comments 2.5.11 Physical aspects - Horizontal pressure differences, caused by temperature variations in the earth/atmospheric system, result in atmospheric motion or wind. Thus, thermal energy is converted to kinetic energy. In the layer near the ground one is concerned with winds of local and micro scale