_Forms of Ice._--Almost all the forms assumed by underground ice are different from those assumed by overground ice. This is not surprising, as the conditions, under which the ice is formed, are so different. Almost all the lines of underground ice are rounded. The sharp angles and fractures visible on glacier or iceberg are absent. Instead of seracs and crevasses, broken ice falls, or piled up ice floes, we have hanging stalactites and rising stalagmites, smooth ice floors and curved ice slopes. This difference is of course due to the fact that most subterranean ice is formed from the drip from the roof or the sides of caves, and because the factor of motion--which plays so large a part in the shaping by fracture of overground ice--is practically wanting. The most striking forms of subterranean ice are the ice stalactites and stalagmites. They descend from the roof as icicles or rise from it as rough cones or pyramids. The icicles are of all sorts of shapes and sizes: sometimes they are tiny; sometimes they grow downward till they reach the floor and form regular columns, in some cases no less than eleven meters in height. The ice stalagmites likewise are of all sorts of shapes and sizes, some of them growing to a height of seven or eight meters. Occasionally they have hollow bases, but this is rare. How these hollow cones are formed is a still uncertain matter; but it is in some way by the action of the drip. At the Kolowratshöhle I saw the drip from the roof cutting out in July the basin, whose tall remaining sides suggested that early in the spring it was probably a hollow cone. The cone at the Schafloch of which I saw one half remaining, could only be accounted for by some action from the drip.[28] The warmth of the rock floor may help perhaps also, in melting away some of the base of the hollow columns. [28] See Part IV.: Thury, page 287; Browne, page 290. The frozen waterfalls which issue from fissures in the rock walls of caves are another form of ice seen only below ground. For lack of a better name, I call them fissure columns. A peculiarity of these is that, while the rock fissure is more or less rectangular or at least sharp angled, the ice column issues in a rounded stream. Sometimes these fissure columns stream over the rock; sometimes they spring out far enough from the rock to be quite away from it. They vary from about one to five meters in height, and at the base they almost always spread out in a shape resembling that of a fan.