Cobwebs attract the dew in a rather singular manner. It is yet to be discovered why the dew forms only upon the horizontal threads of a spider’s web, while the vertical threads, though smaller, collect no dew deposit. This curious fact is well shown in the photograph of the entire spider’s web, also in the section of a web, showing the dew deposit in detail. Wonderfully beautiful are these dew-laden webs. It will be observed that each drop is similar in size, and closely resembles several strings of well-matched pearls, although in the sunshine they appear as clear, flashing diamonds. Certain leaves collect the dew drops in a novel manner, notably the strawberry leaf, and similar plants having serrate edges. The strawberry leaf, besides being plentifully decorated upon its surface with water beads, holds in each tiny serration about its edge a large, clear, sparkling dewdrop, which gives the leaf a wonderful jewelled effect. We are all familiar with the so-called “sweating” of a glass or pitcher, or a metal pipe containing cold water; this is another phase of the dew, and may be observed in the daytime. A cool night in spring or autumn, after a hot day, we usually receive a more copious fall of dew, which gradually increases as the night becomes cooler. Should clouds gather, the precipitation of the dew at once ceases. Wherever a bush or bit of vegetation overhangs a spot, it has a similar effect to that of a cloud, and the dew does not collect at all, or not as copiously, in that spot. In the tropics, and in certain countries where there are no rain clouds; where they rarely have rain for many months at a time, the dewfall is so heavy that it quite supplies the lack of rainfall. If it were not for this providential visitation of the dew all vegetable life must certainly perish, scorched and withered by the torrid heat. [Illustration: 20. Like a piece of bleached coral. Hoar frost discovered under a building] [Illustration: 21. Tabular hoar frost] [Illustration: 22. Tree form tabular hoar frost: grew in zero weather] In the East, in the region of Palestine, the dew frequently is so heavy that it closely resembles rain. Upon the great burning deserts alone the dew never falls; for the moment the dew vapours or molecules encounter the scorching breath which arises from the face of these barren seas of sand, they evaporate and are redissolved, dissipated and consumed by the heat. So it will be seen that the fixed molecules which compose vegetation alone have the power to attract and arrest the water molecules of the air with which they come in contact, and thus form, in combination, the dew. When the temperature is below 32°, the tiny particles which go to form the dew become hoar frost. It is often of great value to the farmer or vegetable grower to be able to know just the temperature of the dew point, because, if he discovers it in time, he is enabled to save his garden from a sudden blighting visitation of the frost.