ACCOUNT OF A DISCOVERY OF NATIVE From the Philosophical Transactions of the Royal Society of London, Vol. XCVI, Part I, 1806, p. 267.-Read April 24, 1806. IN A LETTER TO THE RIGHT HON. SIR JOSEPH BANKS, K. B. P. R. S. MY DEAR SIR: I beg leave to acquaint you with a discovery which I have lately made, as it adds a new, and perhaps it may be thought an interesting, species to the ores of lead. I have found minium native in the earth. It is disseminated in small quantity, in the substance of a compact carbonate of zinc. Its appearance in general is that of a matter in a pulverulent state, but in places it shows to a lens a flaky and crystalline texture. Its colour is like that of factitious minium, a vivid red with a cast of yellow. Gently heated at the blowpipe it assumes a darker colour, but on cooling it returns to its original red. At a stronger heat it melts to litharge. On the charcoal it reduces to lead. In dilute white acid of nitre, it becomes of a coffee colour. On the addition of a little sugar, this brown calx dissolves, and produces a colourless solution. By putting it into marine acid with a little leaf gold, the gold is soon intirely dissolved. When it is inclosed in a small bottle with marine acid, and a little bit of paper tinged by turnsol is fixed to the cork, the paper in a short time entirely loses its blue colour, and becomes white. A strip of common blue paper, whose colouring matter is indigo, placed in the same situation undergoes the same change. The very small quantity which I possess of this ore, and the manner in which it is scattered amongst another substance, and blended with it, have not allowed of more qualities being determined, but I apprehend these to be sufficient to establish its nature. This native minium seems to be produced by the decay of a galena, which I suspect to be itself a secondary production from the metallization of white carbonate of lead by hepatic gas. This is particularly evident in a specimen of this ore which I mean to send to Mr. GREVILLE, as soon as I can find an opportunity. In one part of it there is a cluster of large crystals. Having broken one of these, it proved to be converted into minium to a considerable thickness, while its centre is still galena. I am, &c., CASSELL IN HESSE, March 2d, 1806. JAMES SMITHSON. From the Philosophical Magazine, Vol. XXXVIII, 1811, p. 34. After I had communicated to the president the account of the discovery of native minium, printed in the Philosophical Transactions for 1806, I learned that this ore came from the lead mines of Breylau in Westphalia. 3 ON QUADRUPLE AND BINARY COMPOUNDS, PARTICULARLY SULPHURETS. From the Philosophical Magazine, London, Vol. XXIX, 1807, p. 275. Read December 24, 1807. A paper, by Mr. Smithson, on quadruple and binary compounds, particularly the sulphurets, was read. The author seemed to doubt the propriety of the distinction, or rather the existence, of quadruple compounds, believed that only two substances could enter as elements in the composition of one body, and contended that in cases of quadruple compounds, a new and very different substance was formed, which had very little relation to the radical or elementary principles of which it was believed to be composed. This opinion he supported by reference to the sulphurets of lead (galena) and of antimony, and to the facts developed by crystallography. In the latter science he took occasion to correct and confirm some remarks of his in the Transactions for 1804, on different crystals, which he acknowledged have not hitherto been found in nature. ON THE COMPOSITION OF THE COMPOUND SULPHURET FROM HUEL BOYS, AND AN ACCOUNT OF ITS CRYSTALS. From the Philosophical Transactions of the Royal Society of London, Vol. XCVIII, Part I, 1808, p. 55.—Read January 28, 1808. It is but very lately that I have seen the Philosophical Transactions for 1804, and become acquainted with the two papers on the compound sulphuret of lead, antimony, and copper contained in the first part of it, which circumstance has prevented my offering sooner a few observations on Mr. HATCHETT'S experiments, which I deem essential towards this substance being rightly considered, and indeed the principles of which extend to other chemical compounds; and also giving an account of the form of this compound sulphuret, as that which has been laid before the Society is very materially inaccurate and imperfect. We have no real knowledge of the nature of a compound substance till we are acquainted with its proximate elements, or those matters by whose direct or immediate union it is produced; for these only are its true elements. Thus, though we know that vegetable acids consist of oxygene, hydrogene, and carbon, we are not really acquainted with their composition, because these are not their proximate, that is, are not their elements, but are the elements of their elements, or the elements of these. It is evident what would be our acquaintance with sulphate of iron; for example, did we only know that a crystal of it consisted of iron, sulphur, oxygene, and hydrogene; or of carbonate of lime, if only that it was a compound of lime, carbon or diamond, and oxygene. In fact, totally dissimilar substances may have the same ultimate elements, and even probably in precisely the same proportions; nitrate of ammonia, and hydrate of ammonia, or crystals of caustic volatile alkali,* both ultimately consist of oxygene, hydrogene, and azote. It is not probable that the present ore is a direct quadruple combination of the three metals and sulphur, that these, in their simple states, are its immediate component parts; it is much more credible that it is a combination of the three sulphurets of these metals. On this presumption I have made experiments to determine the respective proportions of these sulphurets in it. I have found 10 grains of galena, or sulphuret of lead, to produce 12.5 grains of sulphate of lead. Hence the 60.1 *FOURCROY, Syst. des Con. Chem. t. I. p. 88. grains of sulphate lead, which Mr. HATCHETT obtained, correspond to 48.08 grains of sulphuret of lead. I have found 10 grains of sulphuret of antimony to afford 11.0 grains of precipitate from muriatic acid by water. Hence 31.5 grains of this precipitate are equal to 28.64 grains of sulphuret of antimony. The want of sulphuret of copper has prevented my determining the relation between it and black oxide of copper, but this omission is, it is evident, immaterial, as the quantity of this sulphuret in the ore must be the complement of the sum of the two others. But as the iron is a foreign adventitious substance in this ore, it follows that the foregoing quantities are the products of only 96.65 grains of it. 100 parts of the ore are therefore composed of Sulphuret of lead Sulphuret of antimony 49.7 29.6 20.7 100.0 It is impossible not to be struck with the trifling alteration which these quantities require to reduce them to very simple proportions, or to think it a very great violation of probability to suppose that experiments, effected with no errors, would have given them thus: Sulphuret of lead Sulphuret of antimony 50. 30. 20. However, I doubt the existence of triple, quadruple, &c. compounds; I believe, that all combination is binary; that no substance whatever has more than two proximate or true elements; and hence I should be inclined to consider the present compound as a combination of galena and fahlertz; and if so, it will be accurately represented, as far as |