end being open for charging, "and the lower stopped, with the excep tion of a small hole for the passage of the separated metal, which is received in a cast-iron pot placed in front and heated with charcoal. The charge, about halt a cwt. of ore, broken into pieces about half inch cube, occupies about half of the length and rather more than half the area of each tube. When all the tubes are charged the upper ends are stopped by sheet-iron doors, and heat is applied by means of a wood fire upon the grate. The liquid metal soon commences to flow, and is received in the pots in front. If the flow ceases through any obstruction the passage is cleared by an iron rod introduced through the aperture at the lower end. A 7 hen the operation, which usually lasts about an hour, has terminated, the residues in the tubes are removed and thrown into a water trough placed behind the furnace on the charging side, and a fresh supply of ore is introduced. The bismuth collected in the pots is ladled out and cast into ingots of from 25 to 50 lb weight. In a furnace containing 11 tubes about 20 cwts. of ore may be heated daily with a consumption of 63 cubic feet of wood. In Plattuer s modification the furnace is of the reverberatory form, the tubes being placed with their inclined axes in the direction of the flame, an arrangement which allows the use of a smaller fire-grate and a proportionate saving of fuel. At Joachimsthal, ores containing from 10 to 30 per cent, of bismuth are heated in- a finely-ground state with scrap- iron, carbonate of soda, and a little lime and fluor-spar in earthen crucibles, which are heated until the mixture is completely fused, when the contents are poured into iron moulds of a sugar-loaf form. The bismuth collects in the point of the mould, and is covered with a cake of speiss, containing all the nickel and cobalt of the ore with about 2 per cent, of bismuth, which is reserved for further treat ment ; the slag filling the upper part of the mould is thrown away. If the bismuth is sufficiently rich in silver it is cupelled, and the oxide formed is subsequently reduced or revived by fusion with carbon. When argentiferous lead containing bismuth is subjected to cupellation the former metal is oxidized more rapidly than the latter, which accumulates to such an extent that it may often form a notable proportion of the litharge produced towards the end of the process, although not existing in sufficient amount to be appreci able by the ordinary processes of analysis in the original lead. This property has recently been utilized to recover a small quantity of bismuth existing in the silver ores smelted at Freiberg. The last portion of the litharge, and the hearth or test bottom from the silver refining furnace, are heated in quantities of 80 or 100 lb in earthen ware pots with hydrochloric acid until complete solution of the bismuth oxide takes place, the proportion of acid and water being regulated to prevent the formation of insoluble salts. When the liquid is clear it is siphoned off to the precipitating tubs, where it is thrown down as an insoluble oxyehloride by the addition of a large quantity of water. By redissolving and reprecipitating, a purer material is obtained, which is then dried and reduced by fusion in iron crucibles with carbonate of soda and charcoal. The production of bismuth annually in Saxony is about 22 tons, and in Austria about 17 cwt.
The principal properties and reactions of bismuth and its com pounds were described in 1739 by Pott, who gave a summary of the information contained in the earlier writers. Our more exact knowledge of the subject is due to Neumann, Hellot, Geoffrey (1753), John Davy (1812), Lagerhjelm (1815), Stromeyer, and, more recently, Schneider and Nickles.
(h. b.)
BISON, a genus of Ruminant Mammals belonging to the family Bovidce, and comprising two widely separated species the European and American Bisons. They are distinguished from other bovine animals by the greater breadth and convexity of their foreheads, superior length of limb, and the longer spinal processes of the dorsal vertebra, which, with the powerful muscles attached for the support of the massive head, form a protuberance or hump on the shoulders. The bisons have also fourteen pairs of ribs, while the common ox has only thirteen. The forehead and neck of both species are covered with long, shaggy hair of a dark brown colour ; and in winter the whole of the neck, shoulders, and hump are similarly clothed, so as to form a " curly felted mane." This mane in the European species disappears in summer ; but in the American Bison it is to a considerable extent persistent. The European Bison (Bison bonassus), or Aurochs of the Germans, is the largest of existing European quadrupeds, measuring about 10 feet long, exclusive of the tail, and standing nearly 6 feet high. Formerly it was abundant throughout Europe, as is proved by its fossil remains found on the Continent and in England, associated with those of the extinct mammoth and rhinoceros. These remains, while indicating larger proportions in the ancient aurochs than in those now living, do not, in Professor Owen s opinion, exhibit any satisfactory specific distinc tion. Cossar mentions the aurochs as abounding, along with the now extinct Bos primiytnius, in the forests of Germany and Belgium, where it appears to have been occasionally captured, and afterwards exhibited alive in the Roman amphitheatres. At that period, and long after, it seems to have been common throughout Central Europe, the Caucasus, and the Carpathian Mountains. It is now only found in one of the forests of Lithuania, where it is saved from immediate extinction by the protection of the emperor of Russia, but notwithstanding this it is gradually dying out. Many years ago the Lithuanian bisons numbered over 1000, but by the year 1872 they had diminished to 528, and all attempts to domesticate them have failed. The aurochs feeds on grass and the bark of young trees. The American Bison (Bison americanus) has its home on the eastern slopes of the Rocky Mountains, being seldom found to the west of these, and rarely to the east of the Appalachian range. Northwards it extends to lat. 63, and southward as far as New Mexico. Those bisons or buffaloes, as the settlers call them, roam in enormous herds over the western prairies in quest of fresh pastures, being specially fond of the tender grass that springs up after a prairie fire. The two sexes live in separate herds during the greater part of the year, although one or two aged bulls, it is said, always accompany the females. During the rutting season when the sexes come together, the bulls engage in fierce fights among themselves, and at such seasons it is highly danger ous to approach them. At other times they are shy, and retreat before man ; but when wounded they become furious, and then all the dexterity of the practised hunter is needed to make good his retreat. The Indians capture them in various ways; by hunting on horseback, and shooting them with bows and arrows, or with fire-arms ; by snaring them within immense enclosures of snow, which the bisons are unable to overleap; or by attracting the herd towards a precipice, and then setting it in motion from behind, so that those in front are pushed irresistibly forward and over. The American Bison, though still found in considerable numbers, is rapidly diminishing before the advance of the white settler ; and should man in the mean time not succeed in domesticating it, it will probably ere long share the fate which threatens its European congener. To the Indian the bison has hitherto been indispensable as an article of food, and for the many useful purposes to which its horns, skin, and hair are applied. Its hide forms an excellent fur wrapper; its great value in this respect was proved during the Crimean war.
Minor, adjoining the Propontis, the Thracian Bosphorus, and the Euxine. According to Strabo it was bounded on the east by the River Sangarius ; but the more commonly received division extended it as far as the Parthenius, which separated it from Paphlagonia, thus comprising the district on the sea-coast between these two rivers, which was inhabited by the Mariandyni. Towards the west and south-west it was limited by the River Rhyndacus, which separated it from Mysia; and on the south it adjoined the portion of Phrygia called Phrygia Epictetus, and a part of Galatia. The territory thus defined is in great part occupied by mountains and forests, but has valleys and districts near the sea- coast of great fertility. The most important of the mountain ranges is that known as the Mysian Olympus -from its proximity to that province, though properly included within the limits of Bithynia which rises to a height of about 6400 feet. It towers in a commanding manner above the city of Broussa, while it
forms a conspicuous object as seen from Constantinople, at