of Pele's hair, and it may be gathered by the barrelful. A bunch of it is much like finely shredded asbestos." You have probably often seen the beautiful frost pictures that collect on the panes of glass in a room where the ventilation has been neglected. These pictures consist of groupings of ice crystals that collect on the surface of the windows, when the moist vapor-laden air in the room is chilled by contact with their cold surfaces. Now the crystals formed in cooling lavas are sometimes grouped in forms closely resembling frost pictures. A few of such forms are represented in Figs. 28 and 29 in lava from Mt. Loa and Mt. Kea. [Illustration: FIG. 28. FROST-LIKE LAVA CRYSTALS _From Dana's Manual of Geology_] [Illustration: FIG. 29. FROST-LIKE LAVA CRYSTALS _From Dana's Manual of Geology_] Certain varieties of lava, especially that which is found in dikes, form cool, beautiful columns called basaltic columns. They are due to the contraction that occurs on the cooling of the material. Instances of basaltic columns are seen in the Giant's Causeway, on the northern coast of Ireland, as well as in the Isle of Cyclops on the coast of Italy. The general appearance of the latter is represented in Fig. 30. [Illustration: FIG. 30. BASALTIC COLUMNS, ISLE OF CYCLOPS, ITALY] It is a curious fact that the entire mass of basalt does not generally take the columnous form but only certain layers which terminate suddenly above and below at structureless masses of basalt, as shown in Fig. 31. These columns, however, are always found at right angles to the cooling surfaces as seen in the figures. They may, therefore, be inclined at all angles to the horizon. [Illustration: FIG. 31. COLUMNAR AND NON-COLUMNAR BASALT] When molten lava is only thrown up a short distance into the air from a crater it is still partially molten when on falling it again reaches the earth, and therefore clings to any surface on which it falls. There are thus built up curious cones known as _driblet cones_, in which the separate drops covering the sides of the cone can be distinctly traced. Driblet cones are represented in Figs. 32 and 33. Here, as can be seen, the separate drops can be readily traced as they run down a short distance before cooling. [Illustration: FIGS. 32, 33. DRIBLET CONES _From Dana's Manual of Geology_]