Lead (metal)

“ One metal was as easily wrought by him as another. Iron was like clay in his competent hands, and he moulded, cut, and hammered as he willed, using copper, gold, silver, iron, tin, zinc, lead, and antimony simply as pigments, and combining them as a painter would his colors. ”

“ In very truth, even the works of art, elegant, embellished, elaborate, useful, are fashioned in various shapes by the artist from the metals gold, silver, brass, lead, and iron. How few artists could make anything that is beautiful and perfect without using metals? Even if tools of iron or brass were not used, we could not make tools of wood and stone without the help of metal. ”

“ It is claimed too, that lead is a pestilential and noxious metal, for men are punished by means of molten lead, as Horace describes in the ode addressed to the Goddess Fortune: "Cruel Necessity ever goes before thee bearing in her brazen hand the spikes and wedges, while the awful hook and molten lead are also not lacking." [20] In their desire to excite greater odium for this metal, they are not silent about the leaden balls of muskets, and they find in it the cause of wounds and death. ”

“ The chief uses of lead are as metal and in the form of white lead or basic carbonate, as a pigment. Metallic lead is used for water pipe, covering for electrical cables, lining acid chambers and vats, and for shot, bullets and shrapnel. ”

“ Lead forms the chief part of all type metal, as it melts easily and fuses readily with other metals; but lead alone is too soft for the service required of type. Antimony is brittle and gives hardness, and tin is added to impart toughness. Lead and antimony in approximately these proportions make an alloy which has [Pg 27] the unusual quality of expanding slightly, instead of shrinking, when cooling, thus permitting a full, sharp cast in all parts of the mold. Tin flows readily when melted and increases the smoothness of the cast on the surface of the mold. ”

“ After the lead is put into the cupel, it gets immediately covered with a coat of oxide, which resists the admission of the silver to be assayed into the melted metal; so that the alloy cannot form. When a bit of silver is laid on a lead bath in this predicament, we see it swim about for a long time without dissolving. In order to avoid this result, the silver is wrapped up in a bit of paper; and the carburetted hydrogen generated by its combustion, reduces the film of the lead oxide, gives the bath immediately a bright metallic lustre, and enables the two metals readily to combine. ”

“ I will in this place, by way of further illustration of the term phlogiston, add a word or two concerning the necessity of its union with a metallic earth, in order to constitute a metal. Lead, it has been observed, when melted in a strong fire, burns away like rotten wood; all its properties as a metal are destroyed, and it is reduced to ashes. If you expose the ashes of lead to a strong fire they will melt; but the melted substance will not be a metal, it will be a yellow or orange-colored glass. ”

“ When lead is kept nearly at a red-heat in the open air for some time, it is converted into a pigment called red lead; this is a calx of lead. To restore this calx again to metallic lead, it is only necessary to heat it in contact with almost any combustible matter; all these bodies therefore must contain one 421 common principle, which they communicated to the red lead, and by so doing reconverted it to the state of metal. Metals then were regarded as compounds of calces and phlogiston. Thus far the theory works glibly enough ”

“ Castings in bell metal are all more or less brittle; and, when recent, have a color varying from a dark ash-gray to grayish-white, which is darkest in the more cuprous varieties, in which it turns somewhat on the yellowish-red or bluish-red. The larger the proportion of copper in the alloy, the deeper and graver the tone of the bells formed of it. The addition of tin, iron, or zinc, causes them to give out their tones sharper. Bismuth and lead are also often used to modify the tone, which each metal affects differently. ”

“ Lead is a soft metal, fairly malleable, but with little ductility, and still less tensile strength. Though one of the commoner metals, it does not occur as pure metal in Nature. It is diffused in minute quantities through the igneous rocks, and also is found in the sedimentary rocks and in the sea water. Its minerals are few, galena, the sulphide of lead, being the commonest, and at the same time the form in which lead is primarily deposited. ”

“ On these properties of Lead, and of the Glass of Lead, depends the whole business of refining Gold and Silver. It hath been shewn, that as these two metals are indestructible by fire, and the only ones which have that advantage, they may be separated from the imperfect metals, when mixed therewith, by exposing the compound to a degree of fire sufficiently strong to vitrify the latter; which, when once converted into glass, can no longer remain united with any metal that has its metalline form. ”

“ To obtain a white lead of excellent quality for its various uses, it is necessary to produce a substance which possesses sufficient body to cover surfaces to which it may be applied as paint, and it must possess sufficient base to combine with the oil of the paint to form a vehicle or varnish to retain and hold the body on the surface. This is found to be the case with sub-carbonate of lead, or especially with a compound constituted of two or three equivalents of carbonate of lead, with one equivalent of hydrated oxide of that metal. ”

“ What Metal has been concerned in effecting this Change of Colour, is not less easily and certainly discoverable from the Colour itself; than what has influenced the Shape, from the Form. If Lead has furnished the metalline Particles, the Spar is yellow; if Iron, red; if Tin, black; if Copper, it is either greenish or blueish, according to the Quality of the Menstruum Nature has furnished for dissolving the Particles of that Metal, and bringing them into a State of mixing in the Concretion ”

“ Metal is a mineral body, by nature either liquid or somewhat hard. The latter may be melted by the heat of the fire, but when it has cooled down again and lost all heat, it becomes hard again and resumes its proper form. In this respect it differs from the stone which melts in the fire, for although the latter regain its hardness, yet it loses its pristine form and properties. Traditionally there are six different kinds of metals, namely gold, silver, copper, iron, tin and lead. ”

“ The types cast by the type-founder are oblong square pieces of metal, each having, on one end of it, a letter or character, in relief. The metal of which these important instruments are composed, is commonly an alloy consisting principally of lead and antimony, in the proportion of about five parts of the former to one of the latter. ”

“ Uses. The uses of lead in the arts are well known. It enters into the composition of many important alloys (pewter, type-metal, shot-metal, solder, &c.) , it furnishes us with several valuable pigments (chrome yellow, &c.) , and it is extensively used in dyeing. Some of its preparations are employed in medicine.
Ant., &c. Administer an emetic of sulphate of zinc or sulphate of copper, and, if necessary, tickle the fauces with the finger or a feather, to induce vomiting. Should this not succeed the stomach-pump may be had recourse to. ”

“ When first melted, lead is bright, but it soon tarnishes by exposure to the air. It melts at a temperature very low in comparison with most other metals; and when a strong heat is applied, it boils and evaporates.
Lead is much employed in the useful arts. When rolled between iron cylinders to a requisite state of thinness and uniformity, it is used for the covering of houses and churches, notwithstanding the danger, in case of fire, to persons within, who are exposed to a shower of burning metal. ”

“ Consequently, if the lead rests on a porous support, which allows the fused litharge to drain away as fast as it is formed, a fresh surface of the lead will be continually exposed to the action of the air, and the operation goes on until the whole of the lead has been removed. Silver or gold exposed to similar treatment does not oxidise, but retains its metallic condition; so that an alloy of lead and silver similarly treated would yield its lead as oxide, which would sink into the support, while the silver would remain as a button of metal. ”

“ All the simple ideas that go to the complex one signified by the term metal, being nothing but what he before comprehended and signified by the name lead. Indeed, to a man that knows the signification of the word metal, and not of the word lead, it is a shorter way to explain the signification of the word lead, by saying it is a metal, which at once expresses several of its simple ideas, than to enumerate them one by one, telling him it is a body very heavy, fusible, and malleable. ”

“ The lead so prepared usually contains small amounts of silver, arsenic, antimony, copper, and other metals. The silver is removed by Parkes's method, as described under silver, and the other metals in various ways. The lead of commerce is one of the purest commercial metals, containing as a rule only a few tenths per cent of impurities.
Properties. Lead is a heavy metal (den. = 11.33) which has a brilliant silvery luster on a freshly cut surface, but which soon tarnishes to a dull blue-gray color. ”

“ The metal proved to be lead, with no trace of gold, silver, copper, tin, antimony, or mercury, and no sign of organic substance was present. It was thus shown that no extraneous material was used to cement the lead to the glass. ”

“ And now, if those ashes shall be molten with a strong fire, then the ashes which arise out of the imperfect Metals, are turned into Glass, or scoria, but the ashes of the perfect Metals do reduce, and restore themselves into a malleable Body, whether it be Silver or Gold, according as it had this or that Metalline mixture in it; and if you proceed yet farther, with melting the aforesaid scoria in the fire, there will a new Regulus fall out, which contains in it that Metal, which is the noblest next Gold and Silver, viz. Lead, and Copper ”

“ Of course, my dear Cleon, I know that lead is little more than half as heavy as gold. But there are ways of making it up. You can put a great deal more metal in, without its being observed, and almost make up the difference. ”

“ An error, Messire Jacques! None of your formulas end in reality. Alchemy on the other hand has its discoveries. Will you contest results like this? Ice confined beneath the earth for a thousand years is transformed into rock crystals. Lead is the ancestor of all metals. For gold is not a metal, gold is light. Lead requires only four periods of two hundred years each, to pass in succession from the state of lead, to the state of red arsenic, from red arsenic to tin, from tin to silver. ”

“ Red lead is made in two ways—directly from metallic lead or by heating easily decomposed lead salts. When it is made from the metal, the following is the process: the lead, which must be very pure, is melted in a reverberatory or calcining furnace, oxidised to massicot by the air passing over it, and the massicot then, by careful heating, changed into red lead, a process in which particular care must be taken that the mass is not melted. By continued heating the massicot absorbs about 2 per cent. of oxygen, and changes in colour to a bright red. ”

“ When the wood blackens or burns, the lead is hot enough to pour.
Whenever the lead is in melted form and exposed to the air, as in the iron pot, there will be a slight oxidation take place which appears as a yellowish-red scum. Do not confuse this with the dross and dirt which is to be skimmed off, but if the scum gets thick, then skim it off before pouring any of the metal.
PREPARING THE MOULD One of the greatest difficulties in making lead castings has been to get the metal to completely fill the mould. ”

“ This kind of tin owes its superiority, not only to the purity of the ore, but to the care with which it is washed and refined.
Lead is of a blueish white color, scarcely sonorous, unelastic, and, being the softest of all metals, yields readily to the hammer. It generally contains a small quantity of silver. An alloy of this metal with tin forms pewter, and in different proportions soft solder. Its specific gravity is 11.35. Lead ore is very abundant in Scotland, the western parts of Northumberland and Durham, Derbyshire, and many other parts of the world. ”

“ TO COMBINE LEAD WITH OTHER METAL. If you wish for economy in combining lead with the metal in order to lessen the amount of tin which is necessary in the metal, first alloy the lead with the tin and then add the molten copper. ”

“ The same metal when cold gives very different results to what it does when hot, although treated in the same manner. Malleability is the first mark of ductility; but that gives only an imperfect idea of the point to which ductility may extend; nor can simple lead, the most malleable metal, be drawn into such fine threads as gold, or even as iron, which is the least malleable. ”

“ Lead pencil is as much a misnomer as it would be to call a horse a cow. Red lead is an oxide of lead, and white lead is a carbonate of lead, but the black lead used in pencils is neither a metal nor a compound of metal. ”