Manufacturer and Builder 11, 1874
This remarkable metal, thus far little used, but the utility of which has commenced to be better understood, appears to have been known by the ancient authors, who gave it the name of Marcarite. Basilius Valentines, in the fifteenth century, first speaks of it as a metal, and Paracelius, in the sixteenth century, calls it a half metal; Lemery, in the seventeenth century, confounds it first with zinc, and afterward describes how it can be artificially made from arsenious tin; Bergman, in the eighteenth century, correctly determined its nature and properties as a separate metal; while at last, in the nineteenth century, its practical uses have been studied and continually found to be of more extensive application.
Alloys.
Among its uses are those to form alloys which are more fusible and harder than the metals alone. Thus the alloy of bismuth and tin is harder, more sonorous, and elastic than tin, and very frequently used by the pewterers in years gone by, when bismuth was cheap and a drug in the market. At present by its high price its use in alloys is more confined. The socalled Britannia metal consists of bismuth, tin, antimony, and copper; Queen's metal of bismuth, tin, antimony, and lead; easily fusible solder of bismuth, tin, and lead; Wood's metal, the most easily fusible of all alloys without mercury, melting at 150° Fahr., consists of 4 bismuth, 2 lead, 1 tin, and 1 cadmium. If modified so as to contain 15 bismuth, 8 lead, 4 tin, and 3 cadmium, an alloy is obtained perfectly liquid at 140° Fahr., used by dentists for filling teeth, and several other purposes where a cast has to be made requiring a very low temperature. The alloy is hard, but flexible, almost as white as silver, has a strong metallic luster, and works well under hammer and file.
Magic Teaspoons.
We have a form for casting tea-spoons of it, the melting of which is the surprise of visitors when they use them in their cups of hot tea or coffee.
Fire Kings and Salamanders.
We use this alloy also for exhibiting our capacity to stand great heat, by calling it lead, melting it in a kettle over an apparently big fire, and then scraping the melted metal out with our hands, etc., to the great surprise of those who do not know otherwise but that its temperature must be some 600° Fahr.
Some of these alloys, as they melt at a well defined temperature, are used as a bath for tempering steel instruments, such as 1 bismuth and 1 tin, which melts at 280° Fahr. Cake molds for the manufacture of toilet soaps and clichés, or stereotypes, are made of an alloy of 1 bismuth, 2 tin, and 1 lead, which melts at 200° Fahr. In order to make clichés, this compound most be allowed to cool until of a doughy consistency, then it is pressed into the mold.
Another useful application of bismuth is for preventing the explosion of steamboilers. It is applied by closing a hole in the boiler by means of a plate made of one of the above described alloys, which will melt by the heat of the steam when this becomes great enough to be a source of danger, and give a harmless exit to the steam or blow a powerful steam-whistle.
Bismuth, besides making alloys with the above metals, combines with silver, nickel, etc., in different proportions, but not with zinc; when melted together, the metals separate in cooling, when the bismuth is found to contain from 7 to 14 per cent. of zinc, while the zinc contains about 2 per cent. of bismuth. As the chemical equivalent of these metals is 208 and 64 respectively, the first alloy answers to the formula Bi4, Zn and Bi Zn, the latter to Bi Zn 150.
Use in Dyeing.
The compounds of bismuth are useful for different purposes; thus the nitrate of bismuth, mixed with a solution of tin and potash, has been used as a mordant in dyeing black and violet in calico-printing.
Pearl-White.
Bismuth is the basis of the so-called pearl-white used by many ladies as a cosmetic, to give a brilliant tint to a faded complexion. If it contains silver, as is often the case with bismuth, it becomes grayish by exposure to light, therefore the bismuth from which this preparation is made must be free of silver. The way to make it is to dissolve as much bismuth in nitric acid as the acid will dissolve, so as to obtain nitrate of bismuth, then pour water into the solution. As the water robs the nitrate of half its acid, it will cause the formation of subnitrate of bismuth, and as this is insoluble in water, it will be precipitated. This precipitate, when well washed and heated to remove all traces of free acid and moisture, is the old celebrated Magisterium Bismuthi, famous as a medicine for spasms in the stomach, dyspepsia, cardialgia, etc.
Another and better form of pearl-white is the subchlorid of bismuth; it is made by pouring a solution of bismuth in nitric acid, slowly into a solution of common salt, when a precipitate is formed of dazzling whiteness, which was first introduced in France under the name of Blanc d'Espagne, or Spanish-white.
There are two objections to the use of bismuth preparations; one is that exposure to the fumes of sulphureted hydrogen makes it as yellow as it does white-lead; thus we once saw, during a lecture on chemical analysis, the face of a lady in the front row of seats turn streaky yellow in different shades, by the odor of the gas used for analysis reaching her; she had evidently used pearl-white made from bismuth or lead. The other, and main objection, is that notwithstanding the insoluble subnitrate may be taken into the stomach with impunity, (provided not too often or in too large doses,) the soluble compounds of bismuth are poisonous, while even the insoluble ones, when applied constantly to the skin, end in injury to the system.
Enamelling.
The last description of pearl-white, the sub-chlorid of bismuth, forms the basis of the compound used for enamelling the faces of faded beauties, its great opacity causing it to cover all freckles, unsightly spots, and wrinkles, while its unnatural whiteness is easily corrected by the addition of flesh eolors made from sulphuret of cadmium, carmine, and its equiv. lents. The main difference between enamelling and the ordinary application is in the vehicle with which the color is applied. Ordinarily the ladies apply the dry powders, white and rouge; but the objection to these is that they rub off easily, especially in warm weather, which objection is fatal in case of intended flirtations, etc. Another way is to apply the powder in a moist condition and rub the excess off when dry; this is an improvement on the dry method, but the art of enamelling is simply to mix the powder with a solution which, when dry, is not soluble in water, and can not rub off when moist — can not even be washed off. There are different kinds of this solution used; some operators make an aqueous solution of gum Angelica, others use alcoholic solutions, some elastic varnishes made out of bleached rubber, etc.; in every case a film is made covering the skin, and we have even seen some artists in this line who, by enamelling, obliterated pock marks which for years had disfigured faces otherwise possessing handsome features.
But the best use of these bismuth compounds is as a flux for enamels on porcelain and metal. They possess the peculiar property to augment the fusibility of the substance without imparting to it any color or changing the color it has. They are therefore the favorite vehicles for the colors made of metallic oxids for painting on porcelain and glass. The gilding of porcelain is also done by its help, being added to the gold in the proportion of one-fifteenth.
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