Page:LA2-NSRW-1-0154.jpg

ASPINWALL fornia and Bermudez in Venezuela. Trinidad contains a lake of asphalt about one mile in diameter, and containing perhaps 6,000,000 tons. An American company exports 100,000 tons a year from this lake to the United States, the supply partly renewing itself by a constant flow of soft pitch from subterranean sources. Bermudez, where an asphalt lake covers 1,000 acres, exports very pure and hard asphalt. In California asphalt was discovered in 1879, and about 1894 beds of very pure, high grade, liquid asphalt were found, which even in its natural state already has the proper consistency for paving. The value of our domestic product almost equals that of the imported product.

Bituminous rock, which is principally used for paving streets, is usually shipped unrefined, and mixed at the place of use with other ingredients. Raw asphalt generally is impure, and must be refined before it can be used. It is manufactured into a cement by mixing it with other forms of bitumen, this cement being used to bind particles of limestone and sand in an asphalt pavement. First the asphalt is melted, the residuum from petroleum being added and this mixture being the paving cement. Clean, sharp sand, heated to 300° is added, and carbonate of lime last. The three substances are mixed thoroughly, and the product is the mixture used, in paving streets. Asphalt is most used for street paying, but it is employed also for the distillation of lubricating and illuminating oils, for cements, for making black Japan varnish, drainpipes of compressed asphalted paper and roofing felts, or paper waterproofed with asphalt, and for waterproofing foundations in bridges and buildings.

Paving streets with asphalt is a simple process. The street is graded solidly to within eight inches of the proposed surface, and rolled. Then a bed of hydraulic concrete is laid, rammed and rolled. On the thoroughness of this preliminary work largely depends the life of the paving. The asphalt is laid in two courses—a cushion one half to one inch deep, and a coat one and ^ne half or two inches thick. The asphalt is applied at a temperature of 250°, dumped and spread evenly with hot rakes. Then hot tampers smooth the surface. It is rolled with three rollers of increasing weight, and sprinkled with cement before the heaviest roller is run. Aspinwall. See .. Ass. The ass, originally domesticated from the wild ass of Abyssinia, differs from the horse in its smaller size and its long hair tufted at the end of the tail. Its fur is usually of a gray color. The unwillingness it shows to cross the smallest stream and its fondness for rolling in the dust point to arid deserts as probably its first home. Its reputation for stupidity is very old. The Egyptians represented an ignorant person by the head and ears of an ass. In the middle ages the Germans of Westphalia made the ass represent Thomas, the unbelieving apostle, and the boy who was last to enter the school on St. Thomas' Day was called the "Ass Thomas." In southern Europe, the ass has been carefully bred and thus greatly improved. The small size of the animal in cold, countries is as much due to neglect as to the climate. In Kentucky, where they are used in breeding mules, being well cared for, they are fifteen hands high on an average; while in the north of India, where they are used by the lowest castes, they are. no taller than a Newfoundland dog. In Syria and Egypt the ass is seen at its best, and is highly prized as a domestic animal. Its milk is very valuable for invalids. Wild asses are hunted in Persia. Assam (ǎs-sǎm' ) a province of British India, situated north of Burma in the valley of the Brahmaputra, acquired by the British in the Burmese War in 1824, and now under the jurisdiction of a British Chief Commissioner. Its area, still largely covered with jungle, in which roam elephants, tigers, leopards and other wild beasts, is 49,004 square miles in extent, with a population, chiefly Hindus and Mohammedans, of about five and a half million. Assam has a heavy annual rainfall, with a climate of moderate temperature; the region, however, is subject to earthquakes. Its chief exports embrace tea, rice, rubber, silk, cotton, ivory and gold; it has also much coal; while petroleum and iron, though as yet undeveloped, are known to exist. In the higher elevations there is much timber. The soil in the valleys and along its chief river, the Brahmaputra, is very fertile, though the excessive rains inundate the land and at seasons imperil the tea-plantations and the rice crop. See Cumming's With the Jungle Folk and Hunter's Statistical Account of Assam; also Bronson's Dictionary in Assamese and English. Assay'ing is the art of finding how much of a given metal there is in a metallic ore or alloy—as, the amount of iron in a specimen of iron ore or the amount of silver in a silver dollar. The term is applied particularly to processes carried out chiefly by fusion or fire assaying; but the word is also applied as wet assaying to the commercial analysis of many things where chemical solvents and reagents are used. Assay processes vary with different metals, but the method used with silver ore will serve as an illustration. The first process is called scorification. One part by weight of ore is mixed with from ten to twenty times its weight of granulated lead and half its weight of borax. This mix-