Page:The fairy tales of science.djvu/304

260 matter is left behind. In course of time a little conical button of spar is formed; and as fresh, matter is constantly being deposited from the water which trickles over it, this button gradually assumes the form of a long stony icicle. Again, the water that falls upon the floor of the cavern, instead of hollowing out a cup-shaped cavity by its continued action during long ages, gradually builds up the accumulation termed the stalagmite, which, rising from the floor, eventually meets the descending stalactite, and thus helps to form a graceful column. When the lapidifying water oozes through a long joint or crevice in the roof, it forms a beautiful transparent curtain of spar; and when it percolates through the sides of the cave, it deposits its calcareous particles in the form of a frozen cascade.

All the sparry ornaments of these underground palaces were formerly held to be the handiwork of the gnomes; and in the present day, those "vacant of our glorious gains" in knowledge, would doubtless regard this opinion with more favour than that which ascribes the fantastic architecture of the caverns to the formative power of a myriad trickling drops of water.

Out of Gnome-land, solid marble is deposited by exactly the same process, wherever water holding carbonate of lime in solution is brought into circumstances favourable to rapid evaporation. Sticks and twigs hanging over brooks often become coated with calcareous matter; and the incrustation of