Chalk

[AS.; L. calx.~\ A form of soft limestone, widely spread in parts of Europe; not found ing from the chalk. The chalk, in fact, is nearly pure carbonate of lime, wThich a compound of the metal calcium with carbon and oxygen. All limestones can detected in this way by pouring on them a few drops of some acid. Most limestones are com¬ posed of the shells or hard parts of the coral-build¬ ing animals, but chalk is composed of the shells minute swimming or floating animals, whose hard parts, after death, sank to the bottom and collected into thick layers. These were after¬ wards uplifted to the surface and became cliffs beds of chalk. Chalk is used in connection with the blackboard in lecture-rooms and schools. Various preparations of it are made for pastel colors. It is also used as a manure. which has the power of changing its color at will. In a dark place it is white or grayish, but when light is admitted its color changes to red, green, are or brown, in accordance with the color of its loca¬ tion. It lives in trees, and has a very extensible tongue, covered with a sticky secretion, by which it can seize insects and drawr them into its mouth. family which is found in the Alps at a height of more than 8,000 feet above the sea-level. It is like the goat in its looks and habits. Its horns are peculiar, rising straight from the crest of the hind-legs are longer than its fore legs, so that in descending mountains its hind feet catch rough places and its fore feet are set close together and pushed forward. It is acute in scenting man at a when grazing they post one of their number to so quickly that often they make off before the.signal is given. The skin of the chamois is much valued for making chamois leather, which com¬ bines softne with tenacity. “ Chamois leather,” or wash-leather, is now made from the flesh side of sheep skins. originally made in Champagne, France. This wine contains much carbonic acid gas, which causes effervescence when poured out.