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experiment made by an incorporation of aqua fortis with silver and mercury, which, being put into water, the silver expands, and shoots itself into an appearance of a tree, with branches, leaves, and flowers. The result, chemists distinguish by the name of Arbor Dianæ, or Tree of Diana. It is beyond our usual hour of retirement. Adieu: we will resume the same subject to-morrow.
OF THE IMPERFECT METALS.
AUGUSTA. I think you told us, that the silver-tree produced in the experiment you exhibited, was called the Tree of Diana. I see no reason why it should be appropriated to that goddess.
MRS. HARCOURT. I am glad you have proposed this question: it affords me an oppor
tunity of mentioning the chemical names of the metals, of which you ought not to be ignorant. From what motive it is difficult to say, but chemists formerly named each of the metals after one of the planets. Thus, gold is called Sol, after the sun, perhaps from the brilliancy of its colour. Silver is called Luna, or the moon, to the beams of which its whiteness bears an allusion: hence the name of this experiment, as Diana was a figurative representation of that planet. Copper is Venus; and iron Mars, which is very suitable, as Mars is the god of war. The activity of Mercury has occasioned his name to be attached to quicksilver. Tin is called Jupiter; and lead, Saturn.
CECILIA. Copper comes next to gold and silver: has it any of their qualities?
MR. HARCOURT. There are some properties common to all metals, which distinguish them from every other substance, and determine them to be metals. By a little consideration, it is likely that you will be able to find some of them out.
SOPHIA. All the metals that I know, are
shining, and opaque, without the least degree of transparency, which I suppose is the cause of their reflecting light, and answering, when polished, the purpose of a mirror.
CECILIA. Heaviness is a distinguishing quality, as is also a capacity of being fused or melted by fire; and when hardened again into a solid mass by cold, the facility with which they are expanded under the hammer, must not be forgotten.
CHARLES. To which, let me add their ductility, or power of being drawn out to such a surprising length.
HENRY. You have all omitted saying, that they are found in the bowels of the earth. MR. HARCOURT. Well remembered, Henry. But to return to the peculiar properties of copper. It is harder than either gold or silver, and is both malleable and ductile; as it may be drawn into a wire as fine as a hair, or beaten into leaves as thin as those of silver. In a great fire, with free access of air, it smokes, and imparts beautiful green and blue colours to the flame. When a solution of copper in 'aqua fortis is mixed with spirit of wine,
and burnt in a tea-spoon over the flame of a candle, it is found that the mixture burns with the most delightful green flame that can be imagined.
SOPHIA. A fire I once saw, made of wood, among which a quantity of copper-dust had been accidentally scattered, showed all the colours of the rainbow.
MR. HARCOURT. The colour of copper, inclining to a dullish red, you are all, undoubtedly, acquainted with. This metal is procured in several parts of Europe, but most abundantly in Sweden. It is found in glebes or stones, of various forms and colours; which are first beaten small, and washed, to separate them from the earthy particles with which they are mixed; after washing they are smelted, and, when in a state of fusion, the melted matter is run into moulds, by which it is formed into large blocks. The operation of melting is repeated more than once, which, with the addition of a certain proportion of tin and antimony, renders it more pure and beautiful. Amongst other marks of distinction, I must not omit to men
tion, that smelling-salts and copper form a fine blue compound, a solution of which is exhibited to advantage in the windows of chemists.
CECILIA. Is not that green stuff, which is called verdigris, that I have seen upon your dirty saucepans, the rust of copper.
MRS. HARCOURT. Yes, my dear. It is so extremely subject to contract rust, being corroded or dissolved by oils, acids, and salts, that I have long discontinued the use of copper vessels in my kitchen, as being very pernicious to health, unless the greatest nicety be observed in the cleaning of them. Many persons have been severely indisposed from the effects of the poison of copper, though it might be expected that the nauseous taste of the verdigris would be a warning of the danger. The metal itself, when heated, has both a disagreeable taste and smell.
You have quite forgotten to mention brass among the metals.
MRS. HARCOURT. Brass is a composition of copper and spelter, which is also called zinc.
It is made by fusing the copper with lapis