Drosometer
A drosometer (from Classical Greek , drosos, dew + , metron, measure) is an apparatus for measuring the quantity of dew formed in a unit of time per unit area of surface. Description The surface may be either a horizontal metal plate or a leaf hanging naturally, or a bit of wool or cotton representing a large surface of fine fibres. The unit of time is usually one hour, and the measurement is made in the early morning, before the rising sun evaporates the dew. When the apparatus is made self-registering, the surface, with its accumulating dew, hangs at one end of a delicate balance, or from a delicate spiral metallic spring, and by its gradual sinking moves the index that makes the record on a moving sheet of paper. Shortcomings Although many forms have been suggested, yet none have been considered to give results that are comparable with each other from day to day, owing largely to the fact that the slightest change in the surface that receives the moisture alters the quantity of dew that is caught. Even the same bit of wool, when used day after day, changes its nature in this respect. If a metallic surface