In the limestone mountains of the Austrian Alpine countries, numerous large caverns and caves are found, some of which are several miles long. They have been formed by the raising, lowering, and sliding of the layers of sand, or washed out by the stream. In one of these caverns near Peggau, in Styria, Austria, the skeleton of a bear (_Ursus Spelaeus_) and the skull of another bear of the same kind were found, both of which are shown in the annexed cut taken from the _Illustrirte Zeitung_, the detached skull being placed on a board. The place in which these bones were found had never been reached before, as the skeleton was covered by a layer, from four to six inches thick, of stalagmites, which in turn rested on a layer of pieces or chips of bones and carbonate of lime, sand, etc. The bones of the skeleton were scattered over a space about eight square yards, and it required several days' work to remove the layers from the bones by means of a mallet and chisel and to give the bones, etc., a presentable appearance. [Illustration: SKELETON OF A BEAR FOUND IN A CAVE IN STYRIA, AUSTRIA.] The skull on the board is of especial interest on account of the beautiful crystals of calcareous spar, which are from 1/10 to 1/4 of an inch long, and are formed on the inner sides of the skull. The skull is 5-1/2 in. wide between the fangs and 6-3/5 in. wide at the forehead, whereas the skull of the skeleton is only 3-9/10 in. wide at the fangs and 5-1/10 in. wide at the forehead. The skull of the skeleton is 22 in. long. The small white object on the board supporting the detached skull represents the skull of an ordinary cat, thus giving an idea of the enormous size of the bear's skull. The skeleton is 9 ft. 8 in. high, and is one of the largest and most complete that has been found. * * * * * THE HARDNESS OF METALS.