Tin (metal)

“ Tin is an essential ingredient in bell-metal, bronze, pewter, and various other compounds. It may be combined with lead, in any proportion, by fusion; and this alloy is harder, and possesses much more tenacity than tin. The hardest alloy is a composition of three parts of tin and one of lead. The presence of the tin destroys, in a great measure, the noxious qualities of the lead. It is sometimes customary to tin copper vessels with this mixture, and it has been ascertained that such vessels are in no respects injurious. ”

“ It is generally believed that the metal called at present tin was known and employed in the arts, not only in the time of Pliny, but as early as that of Herodotus, Homer, and Moses. This I will not venture to deny; but I can only admit that it is probable, or that the great antiquity of this metal cannot be so fully proved as that of gold, silver, copper, iron, lead, and quicksilver.
Tin is one of those minerals which hitherto have been found in quantity only in a few countries, none of which ever belonged to the Greeks or the Romans503, or were visited, at an early period, by their merchants. ”

“ The whole is then left to itself, when crystals of tin gradually separate out on the bottom of the basin.
Properties of Pure Tin.—An ingot of pure tin is pure white (ex cept for a slight tinge of blue) ; it exhibits considerable lustre and is not subject to tarnishing on exposure to normal air. The metal is pretty soft and easily flattened out under the hammer, but almost devoid of tenacity. That it is elastic, within narrow limits, is proved by its clear ring when struck with a hard body under circumstances permitting of free vibration. ”

“ It is a light, soft metal, and, like lead, is easily melted; it is used chiefly for coating vessels of harder metal, such as iron and copper. It is used to mix with copper to produce bronze, bell metal, and gun metal, and with lead to produce pewter, which used to be so extensively used as table-ware before the manufacture of earthenware became general for that purpose. Tin does not easily tarnish or rust by exposure to the air, hence the use of tinned iron-plate. Tin, united with mercury, forms the silvering for looking-glasses. Tin is about seven-and-a-half times heavier than water. ”

“ TIN (Etain, Fr.; Zinn, Germ.) ; in its pure state, has nearly the colour and lustre of silver. In hardness it is intermediate between gold and lead; it is very malleable, and may be laminated into foil less than the thousandth of an inch in thickness; it has an unpleasant taste, and exhales on friction a peculiar odour; it is flexible in rods or straps of considerable strength, and emits in the act of bending a crackling sound, as if sandy particles were intermixed, called the creaking of tin. A small quantity of lead, or other metal, deprives it of this characteristic quality. ”

“ The circumstance also, that vessels of tin have never or very seldom been found among Greek or Roman antiquities, and that when discovered the nature of the metal has been very doubtful, though tin is not apt to change from the action of the air, water, or earth, and at any rate far surpasses in durability copper and lead, ancient articles made of which are frequently found, appears to me worthy of attention. It possesses also so many excellent properties, that it might be expected that the people of every age, to whom it was known, would have employed it in a great variety of ways. ”

“ It consists in applying to the clean and dry metallic surface a film of a pasty amalgam of tin with mercury, and then exposing the surface to heat, which volatilizes the latter, leaving the tin adhering to the metal.
The immersion process is the best adapted to coating articles of brass or copper. When immersed in a hot solution of tin properly prepared the metal is precipitated upon their surfaces. One of the best solutions for this purpose is the following:—
The articles to be tinned must be first thoroughly cleansed, and then kept in the hot solution until properly whitened. ”

“ The application of tin to the coating of other metals has been carried to great perfection, and it forms the chief ingredient in various kinds of pewter and other white metallic alloys, such as Britannia metal, which are manufactured into domestic utensils by casting, stamping, and other ingenious processes. Tin is the substance which, coated with quicksilver, makes the reflecting surface of glass mirrors. ”

“ An alloy of this nature is sometimes separated from ordnance bronze by incorrect treatment, causing the so-called tin spots; but this has not the pure white color which distinguishes the speculum metal containing 31.5 per cent of tin. By increasing the percentage of copper the color gradually shades into yellow; with a larger amount of tin into blue. It is dangerous to increase the tin too much, as this changes the other properties of the alloy, and it becomes too brittle to be worked. ”

“ I observed, “that it is when mixed with tin that mercury forms the amalgam used for the backs of mirrors.”
“Mercury is not the only metal which unites in a friendly manner with tin. Joined to copper, it becomes bronze, of which those pretty chimney-piece ornaments are made; and pewter, so useful to the poor, comes from tin united with lead. It is also very commonly used to line copper pots and pans, which, without such a coating of tin, might poison the food which they contain.” ”

“ The tinning consists of an alloy of tin and lead, which is much less easily attacked than the copper, and the safety of which is farther insured by the circumstance, that the substances endowed with the property of dissolving lead, cannot attack that metal before the whole tin of the alloy is oxidated. ”

“ Tin is sometimes found native or pure, but most frequently alloyed with other metals: the working of tin mines is attended with much difficulty, on account of their great depth, and the hard rocks which obstruct the progress of the miners, who are often obliged to cut through them. This metal is very useful in the making of domestic utensils, for coating the inside of copper and iron vessels, and for various other purposes. ”

“ To extract the metal from the tin ore, a fierce heat, long applied, was necessary, but a slight heat, continued for a few minutes, sufficed to melt the metal. This remelted metal was poured into a stone mould, where it lay like a bright little pool of liquid silver. In a few seconds it solidified, retaining its clear purity in all its parts.
“That,” said the agent, “is tin of the very best quality. We sell it chiefly to dyers, who use it for colouring purposes, and for whom no tin but the best is of any use. ”

“ Low quality tin ores containing iron, copper, lead, zinc, antimony, etc., combined with arsenic, sulphur, or oxygen, will give very much higher results than the actual percentage of tin in the sample. The other metals (being readily reduced in the presence of tin) alloy with it, and give a hard lump difficult to fuse in the iron ladle; where the quantity of foreign metals is large, the metal can only be melted to a stiff pasty mass ”

“ The particles of tin are indeed set free by the stamps from solid bondage, but they are so fine as to be scarcely visible, and so commingled with other substances, such as iron, copper, sulphur, etcetera, that a tedious process of separation has yet to be undergone before the bright metal can be seen or handled. ”

“ The beautiful mosaic gold (aurum musivum) , a pet product with many alchemists, was probably the first [425] tin compound to be used in medicine. It was made by first combining tin and mercury into an amalgam, and then distilling this substance with sulphur and sal ammoniac. It is now known to be a bisulphide of tin. The mercury only facilitates the combination of the tin and the sulphur, and the sal ammoniac has the effect of regularising the temperature in the process. The product is a beautiful golden metal of crystalline structure and brilliant lustre. ”

“ Iron ores are found everywhere, and are so little regarded for their metallic contents that, though containing, according to Mr. Logan, a skillful geologist, sixty percent of pure metal, they are used in Singapore for macadamizing the roads! Gold has been obtained in all ages, and formerly in considerable quantities, but the annual yield does not now exceed nineteen thousand ounces. The vastest tin fields in the world are found in the western Malay States, and hitherto the produce has been "stream tin" only, the metal not having been traced to its veins in the rock. ”

“ Stream tin is generally associated with alluvial gold. When such is the case there is no difficulty in saving the gold if you save the tin, for the yellow metal is of much greater specific gravity. As the natural tin is an oxide, and therefore not susceptible to amalgamation, the gold can be readily separated by means of mercury.
Lode tin sometimes occurs in similar quartz veins to those in which gold is got, and is occasionally associated with gold. Tin is also found, as at Eurieowie, in dykes, composed of quartz crystals and large scales of white mica, traversing the older slates. ”

“ Another substance capable of existing in more than one crystalline form, is the metal tin, and although the general behaviour, so far as studied, is analogous to that of sulphur, a short account of the two varieties of tin may be given here, not only on account of their metallurgical interest, but also on account of the importance which the phenomena possess for the employment of this metal in everyday life. ”

“ It is well known that alchemists, with their strange system of nomenclature, believed there was a certain mysterious relation between the seven metals then known and the seven planets; each metal was dedicated to a planet; tin was called Jupiter; silver, [Pg 325] Luna; gold, Sol; lead, Saturn; iron, Mars; quicksilver, Mercury; and copper, Venus. The crystallization of tin may be recognised also by rubbing a piece of this metal with hydrochloric acid; the fragments thus rubbed off exhibit specimens of branching crystals similar to the hoar-frost which we see in severe winter weather. ”

“ A kind of ware, called biddery ware, is made of tin alloyed with a little copper. The vessels made of this composition, are rendered black by the application of nitre, common salt, and sal ammoniac. Foil is also made by pressing it between steel rollers, [237] or by hammering it, as in the case of gold by the gold-beaters.
15. But tin is most extensively applied as a coating to other metals, stronger than itself, and more subject to oxydation. The places which are usually denominated tin, are thin sheets of iron coated with this metal. ”

“ The tin dioxide used in the glaze is made by direct oxidation of tin in air. It has been found that tin burns much more easily in air when it is mixed with lead; 20 to 40 parts of tin are melted with 100 parts of lead, and the alloy heated in shallow vessels in the air; it takes fire [Pg 321] at a certain temperature, and it is only necessary to remove continually the layer of oxide in order to oxidise the whole of the metal within a short space of time. The mixture of oxides obtained in this manner is freed from particles of metal by grinding and levigation ”

“ Ninety per cent of tin and 10 per cent of antimony gives a composition which is the best for many purposes, especially for casting, as it fills out the molds well, and is readily fusible. In some cases, where articles made from it are to be subjected to constant wear, a harder alloy is required. In the proportions given above, the metal is indeed much harder than tin, but would still soon give way under usage. ”

“ For instance, a solder in which tin forms a component part will flow or fuse much sooner than one in which copper and silver alone enter into composition, or of one wholly composed of copper, silver, and zinc, or of silver and brass; therefore it must be understood that tin is the best metal for increasing the fusibility of silver solders, and for keeping up their whiteness. ”

“ Tin is white, a little elastic, and so exceedingly soft and ductile, that it may be beaten out into leaves thinner than paper. It is much more combustible than many of the metals; and is soluble in all the mineral acids. Its specific gravity is 7.291, or about 516 pounds to the cubic foot. This metal is found in Germany, Saxony, South America, the East Indies, and in England, chiefly in Cornwall and Devonshire. It must have been known very early, as it is mentioned in the books of Moses. ”

“ If the metal on cooling remains perfectly clear and bright, then it may be assumed that the tin is of good quality and commercially pure. A crystallised or frosted appearance of the metal indicates the presence of some alloy, say of iron, copper, zinc, lead, antimony, &c. The assayer who has had much practice can readily distinguish the metal or metals that are associated with the ore by noting the appearance of the tin on cooling ”

“ C. 3.—But while the ancients dreaded the Ocean, they knew also that its islands alone were the source of one of the most precious and rarest of their metals. Before iron came into general use (and the difficulty of smelting it has everywhere made it the last metal to do so) , tin had a value all its own. It was the only known substance capable of making, along with copper, an alloy hard enough for cutting purposes—the "bronze" which has given its name to one entire Age of human development. ”