BISMUTH BISON 667 hence one of its chief uses is to prepare alloys that will melt at very low temperatures. A mixture of two parts of bismuth, one of lead, and one of tin, will melt at 200 F. ; and spoons are often cast of this alloy, to be used as toys, melting away instantly in any hot liquid. One part of bismuth, two of tin, and one of lead form a soft solder for pewterers. It is also employed as a bath for tempering steel, and as a cake mould for toilet soap. Another al- loy, composed of 5 parts of bismuth, 3 of lead, and 2 of tin, melts at 199 F., and is known as stereotype metal. An amalgam of 20 parts of bismutli and 80 parts of mercury is extensively used for silvering the interior of glass globes, and for similar ornamental purposes. Dr. Wood of Nashville, Tenn., discovered an alloy still more fusible than any of those above mention- ed. It is composed of 8 parts of bismuth, 4 of lead, 2 of tin, and 2 of cadmium, and is said to melt at 158 F. One of the earliest compounds of bismuth that received any attention, the preparation of which was for a long time kept a profound secret, is the subnitrate, now known under the name of pearl-white. This salt is ex- tensively used for enamels on porcelain, and also in gilding. It has great solvent properties with other oxides, especially with silica and borax ; and as it imparts no color, it is valuable in the manufacture of porcelain and of optical glass. The nitrate, mixed with a solution of tin and tartar, has long been employed as a mordant for dyeing lilac and violet in calico printing. Pearl-white is principally used as a cosmetic to give a brilliant tint to faded complexions. Sul- phur converts the salts of bismuth into the black sulphide of bismuth, so that the smallest trace of sulphur in the illuminating gas may gradually turn the pearl-white to a dark hue. If we write with a pen dipped in a solution of the nitrate of bismuth, after it is dry nothing can be seen ; but on plunging the paper into water the writing will become distinctly visi- ble. Mr. Farmer of Boston has invented an ingenious thermo-electric battery, composed of a row of bars of an alloy of antimony and bis- muth, which only require to be heated to ex- cite a powerful galvanic current. The sim- plicity of the arrangement, the avoidance of acid fumes, the constant readiness for use, and the facility with which it can be set in action, commend this form of apparatus to the atten- tion of physicists. It is evident that if by sim- ply heating one end of a metallic bar a suffi- ciently powerful current can be excited to pro- duce all the effects of an ordinary galvanic bat- tery, this would afford the most convenient and economical arrangement for the telegraph, for electro-plating, and in fact for all the purposes to which the old form of battery is now ap- plied. The spectrum of bismuth presents a multitude of brilliant rays in the green, a faint and one strong ray in the red, and a feeble one in the orange. According to Wagner, the pro- duction of bismuth in Saxony in 1871 was 32,000 Ibs. The subnitrate of bismuth is used medicinally in painful affections of the stomach, such as cancer, cardialgia, chronic ulcer, and chronic inflammation. Its action seems to be a local one, little or none of the drug being absorbed. It may be considered either as as- tringent or more probably as simply protecting irritable surfaces mechanically. It has also been used with advantage in chronic diar- rheas. It has been applied externally in eczema and allied conditions of the skin and mucous membranes. The carbonate may be employed in the same way as the subnitrate, and in the same doses. From 5 to 15 grains may be given three times a day. Some prac- titioners have given two or three drams at once, but such doses are not to be recommended. BISON, a name given to three species of the ox family. 1 . The European or Eur- Asiatic species, bos itrus, known as the bonassug, is supposed to be the ancient urug or aurochs. (See AUEOOHS.) 2. The Indian bison (B. gaunis) is but partially known and imperfectly described. It has the general characteristics of the bisons, the short horns, huge head, unshapely forehead, and the vast masses of shaggy wool covering those parts. It frequents the Ghauts and the wild- est forest ranges of the Himalaya. 3. The bison, commonly and erroneously called buffalo, of North America (B. Americanus), is distinguish- ed by its singular hump over the shoulders ; this hump is of an oblong form, diminishing in height Bison Americanus. as it recedes, so as to give considerable obliquity to the line of the back. The eye is black and brilliant ; the horns are black, and very thick near the head, whence they curve upward and outward, tapering rapidly toward the point. The outline of the face is convexly curved, and the upper lip on each side, being papillous within, dilates and extends downward, giving a very oblique appearance to the lateral gap of the mouth, in this particular resembling the ancient architectural bass reliefs representing the heads of oxen. The physiogomy of the bi- son is menacing and ferocious; but this appear- ance is a mere outward show, since of all the
