From this it seems to me that alum contains, as truly as the phosphates, water of constitution, which when expelled from the salts, leaves it a body altogether different.* I would also call to mind that the anhydrous chlorid of aluminium is a body volatile without decomposition, while the crystallized hydrochlorate of alumina is decomposed by heat into hydrochloric acid and pure alumina. The conclusions which follow from the facts I have instanced, may be summed up in the following manner: The expressions neutral salt, basic salt, acid salt, are arbitrary terms, used to designate particular types of salts which differ from each other by the elements of H2 O, or of the metallic oxyd M* 0. These types are interchangeable, with greater or less facility, according to certain conditions of mass, of temperature, etc., which it is impossible to determine with precision in the present state of the science; and there are absolutely the same chemical relations between the metaphosphates, the pyrophosphates and the ordinary phosphates, as between the nitrates and the basic nitrates, the sulphates, the bisulphates and the subsulphates, the chlorids, the hydrochlorates and the oxychlorids, etc. It cannot be said exclusively in the ordinary acceptation of the terms, that any particular salt is monobasic, bibasic or tribasic. When the reactions take place in water, as is almost always the case, the types of the salts are modified or remain unchanged according to the degree of their stability; sometimes they remain unaltered, at others they combine with the elements of the water or of a metallic oxyd, and then give rise to a new type. But there is no rule for predicting these modifications. To make my idea more intelligible, I will write out a few formulas. 2 Genus PHOSPHATE, PO (M2)+M2 O. A. Sub-genus perphosphate, 5 PO (M2) - ¦ M2 O=PO3 (M)=[P2 O3, M2 O]. All the so-called metaphosphates will belong to this type. B. Sub-genus equiphosphate, PO (M2)=[P2 O3, 2M2 O]. It includes a few pyrophosphates, and especially the salt of soda dried at 212° F., PO (Na2 ). *I will take this occasion to remark that, the cubical alum has exactly the same composition as the alum in octahedrons. The formation of cubical alum or Roman alum belongs to the class of phenomena of crystallization so well investigated by M. Beudant. I shall give in my work all the proofs respecting it. M. Jacquelain (Comptes Rendus de l'Acad., t. xxiv, p. 44) affirms that alum contains 22 atoms of water instead of 24 in the usual formula. This assertion is not accurate, for the new formula would require 43.38 per cent. of water, and we obtain, by direct determination, 45.5 per cent. Now this is exactly the same number cubical alum also gave me. C. Sub-genus a subphosphate, PO (M2)+M2 O=PO' (M3)=[P2 O5, Phosphate of soda called neutral, at 2120 F., 66 of silver, แ of lead, . D. Sub-genus subphosphate, 3M2 O]. PO (M2)+M2 O=POZ (M1)=[P2 O3, 4M2 O]. Phosphate of soda called basic, at 2120 F., PO? (Na3 H). of baryta at 212° F., Pyrophosphate of baryta at 212° F., Basic phosphate of lead, PO (Ba3 H). PO (Ba H). PO (Pb). Genus SULPHATE, SO (M2)+M2 0. A. Sub-genus persulphate, SO (M2) - M2 O=SO2 (M)= [2SO3 M2 O]. Fuming sulphuric acid, SO (H). Crystallized anhydrous bisulphate of potash, SO (K). B. Sub-genus equisulphate, SO1 (M2)=[SO3, M2 O]. Concentrated sulphuric acid, Neutral sulphate of potash, Bisulphate of potash at 212° F., Insoluble alum, White sulphate of copper, C. Sub-genus & subsulphate, SO' (M2)+M2 O=SO3 (M1)=[SO3, 2M2 O]. A salt obtained by boiling a mixture of SO5 (H1). sulphate of copper and neutral sulphate (SO3 (KH1⁄2 Cu2 ). of potash, at 212° F., б D. Sub-genus & subsulphate, SO1 (M2)+2M2 O=SO® (M®)= [SO3, 3M2 O]. Turpeth mineral, SO (Hg). Genus CHLORID, Cl2 (M2)+M2 O. There cannot be any perchlorids. Cl2 (M2)+M2 O=Cl2 O (M1)= [C12 M2, M2 O]. I give the name of equisalts to those which correspond to the acids produced by the combination of equal volumes of hydrogen and a non-metallic body (for example, hydrochloric gas), or by the direct combination of equal volumes of water and an anhydrid (for example, concentrated sulphuric acid). The subsalts contain the elements of an equisalt, plus nOM2, the persalts are composed of the same elements minus nOM2. These definitions appear to me much more precise than the names applied to the same combinations in the dualistic system. The researches of which I have just given the first results, will soon be followed by a volume on mineral chemistry, in which I shall discuss more at length the principles of the unitary system (système unitaire), which along with M. Laurent, I am endeavoring to establish." ART. XXXII-Observations on Rammelsberg's Analysis of the Juvenas Meteoric Stone, and on the Conclusion of Fischer's Examination of the Braunau Meteoric Iron; by CHARLES UPHAM SHEPARD, M.D. THE two memoirs here referred to, are contained in the Annalen der Physik und Chemie, von J. C. Poggendorff, Band lxxiii, Stuck 4, (1848). 1. Rammelsberg's Analysis. This chemist commences his paper by a reference to my report on meteorites published in former numbers of this Journal,† and especially to the circumstance of my assigning the feldspathic mineral in the Juvenas stone to the species anorthite; it having been previously referred by Haüy and Laugier to feldspar, and by Rose to labradorite. This led him to undertake a fresh analysis of the meteorite, Alexander von Humboldt having supplied him with a specimen for the purpose. The investiga "Das tion confirms my opinion respecting the mineral in question, while Rammelsberg affirms that it has led to new results. Resultat ist nun allerdings zu Gunsten der Ansicht von Shepard ausgefallen, und liefert noch einige vielleicht nicht ganz uninteressante Details." My report on meteorites having been mainly devoted to such productions as had been observed in the United States, it was not thought proper to allude to foreign localities, except in a very concise and general manner. This brevity led Rammelsberg to doubt whether my inference respecting the feldspathic ingre * I have elsewhere shown (Journ. de Pharm. et de Chimie, t. xi, p. 379) how we can estimate, by analogy, the volume of a non-volatile anhydrid in the state of vapor, by taking as a basis the known volume of the corresponding anhydrous ↑ Vol. ii, ii ser., p. 377, and iv, p. 74. chlorid. dient of the Juvenas stone was made from the descriptions of others, or had resulted from a new examination of the mineral itself. I may therefore be allowed to state, that it was formed from an examination of a large specimen of the Juvenas stone, that had been supplied to me by H. Heuland, Esq., out of the fine meteoric cabinet of the late Sir F. Chantrey. Besides, I am ignorant of the fact, if any writer has noticed the particular crystal I have figured of the anorthite, or made the observations respecting the sphenomite of the Juvenas stone which were included in the same paper. Rammelsberg finds the Juvenas stone to consist of the following minerals: Magnetic pyrites, With perhaps minute traces of apatite and rutile. The anorthite is soluble in moderately strong hydrochloric acid; and consists of: The augite was insoluble in hydrochloric acid; and was decomposed by carbonate of soda (and by hydrofluoric acid for determining the soda content). It contained: In supposing that the phosphoric and titanic acids were for the first time discovered in meteorites by the present research, Rammelsberg has overlooked my announcement of the existence of the first of these in 1829, in the Virginia stone,* the reaffirmation in 1843,† of its presence in the same stone (in answer to the doubt expressed by Rumler in relation to the subject in Pogg. Band liv, Stuck 2, 1841), and repeated allusions to the same point in my recent meteoric reports: while, concerning titanic acid, it has also escaped him, that I gave in my report the following reasons for supposing that it existed in the Juvenas stone under my description of sphenomite. "Thus named from its resemblance to sphene. It occurs in brownish-grey (with a tinge of yellow) thin, tabular crystals, H. =5.5. Implanted on crystals of black pyroxene, and associated with anorthite in the Juvenas stone. Before the blowpipe, it fuses readily to a black glass, which is magnetic. It dissolves in borax with effervescence, presenting the reaction of sphene. It is soluble in nitric acid, with the exception of a heavy white powder, insoluble in ammonia. This solution contained silicic acid and lime." I was therefore led to regard the presence of titanic acid as nearly certain in the meteorite; and accordingly twice referred to titanium in the course of the report, as a probable ingredient of meteors. I am not, however, certain that the phosphoric acid exists combined with lime, in the form of apatite. It is possible that magnesia enters into the compound, and that the mineral constitutes a new species. Nor can I yield to the suggestion, that the supposed titanic acid exists as rutile. On the other hand, I believe it to be present in the sphenomite, in which I also detected silicic acid, lime and protoxyd of iron. 2. Fischer's Analysis. The first part of Fischer's research respecting the Braunau iron appeared in the Annalen, Band Ixxii, S. 475, and was translated by Mr. Lettsom for this Journal (vol. v, ii ser., p. 338). The principal portion of the present article relates to the composition of the insoluble ingredient of the iron, concerning which Fischer observes, that it has very properly been called Schreibersite by the Vienna naturalists. Now this is the name by which, in 1846, I designated the sulphuret of chromium, found in the Bishopsville (S. C.) meteoric stone, one year before the fall of the Braunau iron occurred. And I had moreover described in my report on meteorites, the very ingredient of meteoric irons with which Fischer occupies himself in the present inquiry, under the name of dyslytite. Whether there has been an accidental interchange of my names, or whether some writer has named the insoluble substance in ques * See this Journal, vol. xvi, p. 199. + Ibid, vol. xlv, p. 102. |