Bismith, a metal which shines with such brilliant colors that the name is supposed to be derived from the German Wiesenmatte, or meadow lawn. The original word was contracted to Wissmat, and finally to Wismuth, which is its present German form. The ancients make no mention of bismuth. It is not more than 100 years since a number of the moat learned scientific men of Europe stoutly maintained that it could be made artificially, and was not therefore a simple body. After the properties of the metal became well understood search was made everywhere for it, and it was found native in a number of localities - the principal mines being in Saxony, where it is associated with nickel and cobalt to the extent of 7 per cent. Specimens of it have been found in Monroe county, N. Y.; in South Carolina; in Haddam, Conn.; in Virginia; and in several places in South America, especially on the Andes in Bolivia at a height of 15,000 feet. At the mines in Saxony the impure ore is eli-quated or subjected to a sweating process, and the drops of the metal, as they ooze out, run down the pipes into iron kettles. In this way the crude ingots are prepared for commerce. - Pure bismuth is a reddish-white metal, closely resembling antimony.
It is so brittle that it can be pulverized in a mortar, and yet at certain temperatures it is more or less tenacious, and can be drawn into thin wires. By fusing large quantities of it, say 100 lbs., in a kettle well covered, and then as soon as a thick crust has formed piercing two holes, pouring out the still liquid contents, and sawing off the upper crust, there will be disclosed magnificent crystals with cubical facets, and in clusters, resembling a ruined city. These crystals have all the iridescence and play of colors of the rainbow'. The specific gravity of the metal is 9.83, and it melts at 264 C. (507° F.). This point of fusion is used to adjust high-ranged thermometers. An alloy of antimony and bismuth, arranged in a great number of small prisms, affords the most sensitive thermometer that has been constructed. We can measure the 1/10,000 of a degree by this delicate instrument, and by it even the moon can be shown to afford some heat. The principle upon which it is based is the action of heat to produce an electric current which moves a carefully adjusted magnetic needle.
The passage of the hand before the instrument, or the faintest breath, or any radiating surface turned toward it, immediately excites the electric current, and causes the needle to move around the graduated arc; and in this way the slightest change in temperature can be measured. Some celebrated experiments were performed with it by the Italian philosopher Melloni, and also by Dr. John W. Draper of New York, for the purpose of deciding many nice points in reference to the transmission, radiation, and refraction of heat. Melted bismuth expands on cooling, following the same law as iron and water on its conversion into ice. Bismuth imparts brittleness to other metals, rendering even gold and silver less malleable, and forming, it is said, a crystalline alloy with iron. The alchemists looked upon it as a bastard metal, and sometimes called it lead ashes, plum-hum cinereum, on account of its close resemblance to antimony. They also spoke of it as antimonium femininium, or the female antimony. Its frequent occurrence in beautiful dendritic groups also suggested to the early miners that it could be cultivated the same as any tree or vegetable. - Bismuth has the property of imparting fusibility to other metals; 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 alloy, 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 bismuth 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 mentioned. 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 extensively 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. Sulphur 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 visible. - Mr. Farmer of Boston has invented an ingenious thermo-electric battery, composed of a row of bars of an alloy of antimony and bismuth, which only require to be heated to excite a powerful galvanic current. The simplicity 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 attention of physicists.
It is evident that if by simply heating one end of a metallic bar a sufficiently powerful current can be excited to produce all the effects of an ordinary galvanic battery, 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 applied. - 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 production of bismuth in Saxony in 1871 was 32,000 lbs. - 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 astringent or more probably as simply protecting irritable surfaces mechanically. It has also been used with advantage in chronic diarrhoeas. 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 practitioners have given two or three drams at once, but such doses are not to be recommended.