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entirely free from it, while others again are covered with an abundance of rust arising from its decomposition.
Besides the above minerals two others were found-one a siliceous mineral, the other in minute rounded black particles; both, however, were in too small quantity for any thing like a correct idea to be formed of their composition.
The different minerals that admitted of it were examined chemically, and the following are the results:
1. Nickeliferous Iron.-The specific gravity of this iron is, as already stated, from 7.88 to 7.91. It is not readily acted on by any of the acids in the cold; nitric acid, either concentrated or dilute, has no action on it until heated to nearly 200° Fah., when the action commences, and continues with great vigor even after the withdrawal of heat. With reference to the action of sulphate of copper, it is passive, although when im mersed in a solution of sulphate of copper, and allowed to remain for several hours, the latter metal deposits itself in spots on the surface of the iron.
Thorough digestion in hot nitric acid dissolves the iron completely. When boiled with hydrochloric acid the iron dissolves with the liberation of hydrogen, leaving undissolved the schreibersite; but by long-continued action this latter is also dissolved with the evolution of phosphureted hydrogen.
The following ingredients were detected on analysis of twospecimens:
Tin and arsenic were looked for, but neither of those substances detected. The magnesia and silica are doubtless combined, probably in the form of olivine, and disseminated in minute particles through the iron. The phosphorus is in combination with a given portion of iron and nickel, forming schreibersite. The 0.16 per cent. of phosphorus corresponds to 1.15 of schreibersite; so the metal mass may be looked on as composed of nickeliferous iron 98.97, screibersite 1.03-100.00
The composition of the nickeliferous iron corresponds to five atoms of iron and one of nickel: iron, 5 atoms, 82.59; nickel, 1 atom, 17.41=100.00.
2. Protosulphuret of Iron.-This variety of sulphuret of iron found with meteorites is usually designated as magnetic pyrites, leaving it to be inferred that its composition is the same as the terrestrial variety. Without alluding to the doubt among some mineralogists as to the true composition of the terrestrial magnetic pyrites, I have only to say that most careful examination of the sulphuret detached from the meteorite in question proves it to be a protosulphuret-a conclusion to which Rammelsberg had already come with reference to the pyrites of the Seelasgen iron, which latter pyrites I have also examined, confirming the results of Rammelsberg.
This pyrites incrusts some portion of the iron, and in places is mixed with a little schreibersite. It presents no distinct crystalline structure, has a gray metallic luster, and a specific gravity of 4.75. The Seelasgen pyrites gave me for specific gravity 4.681. The specimen of pyrites in question gave, on analysis: iron, 62.38; sulphur, 35.67; nickel, 0.32; copper, trace; silica, 0.56; lime, 0.08-98.91. The formula Fe S requires sulphur 36.36, iron 63.64. The magnetic property of this mineral is far inferior to that possessed by schreibersite.
3. Schreibersite.-It is found disseminated in small particles through the mass of the iron, and is made evident by the action of hydrochloric acid; it is also found in flakes of little size, inserted as it were into the iron; and owing to the fact that in many parts where it occurs chloride of iron also exists, this last has caused the iron to rust in crevices, and on opening these schreibersite was detached mechanically. This mineral as it exists in the meteorite in question so closely resembles mag-" netic pyrites that it can readily be mistaken for this latter substance, and I feel confident in asserting that a great deal of the so-called magnetic pyrites associated with various masses of meteoric iron will upon examination be found not to contain a trace of sulphur, and will, on the contrary, prove to be schreibersite, that can be easily recognized by the characters to be fully detailed a little farther on.
Its color is yellow or yellowish-white, sometimes with a greenish tinge; luster metallic; hardness 6; specific gravity
7.017. No regular crystalline form was detected; its fracture in one direction is conchoidal. It is attracted very readily by the magnet, even more so than magnetic oxide of iron; it acquires polarity and retains it. I have a piece three tenths of an inch long, two tenths of an inch broad, and one twentieth of an inch thick, which has retained its polarity over six months; unfortunately the polarity was not tested immediately when it was detached from the iron, and not until it had come in contact with a magnet, so that it can not be pronounced as originally polar.
Before the blowpipe it melts readily, little blisters forming on the surface from the escape of chlorine, and blackens. The magnet is a most ready means of distinguishing the schreibersite from the pyrites commonly found in meteoric irons; for, although the pyrites is attracted by the magnet, it is necessary that the latter should be brought quite near to it for the effect to be produced; whereas if the particles exposed to the magnet be schreibersite, they will be attracted with almost the readiness of iron filings.
Hydrochloric acid acts exceedingly slow on this mineral when pulverized with the formation of phosphureted hydrogen. Nitric acid acts more vigorously, and readily dissolves it when finely pulverized. The composition of this substance has in all cases but one been made out from the residue of meteoric iron, after having been acted on by hydrochloric acid, which accounts for the great variation in the statements of the proportion of its constituents.
Mr. Fisher examined pieces of schreibersite detached from the Braunau iron with the following results: iron, 55.430; nickel, 25.015; phosphorus, 11.722; chrome, 2.850; carbon, 1.156; silex, 0.985-98.158.
The results of my analyses do not differ very materially from this. They are as follows:
Nos. 1 and 2 were separated mechanically from the iron; No. 3 chemically. The silica, alumina, and lime were almost entirely absent from No. 3, and in the other specimen they are due to a siliceous mineral that I have found attached in small particles to the schreibersite. There is no essential difference in my results; yet in neither instance do I suppose the mineral was obtained perfectly pure, although enough so, it is believed, to furnish the correct chemical formula; and as from what has been previously said schreibersite will be found to exist in larger quantities than it was suspected, it will not be long before the question of the uniformity of its composition will be settled, a point of interest bearing upon the theoretical consideration of meteoric stones.
The formula of schreibersite I consider to be Ni2 Fe1 P.
This mineral, although not usually much dwelt upon when speaking of meteorites, is decidedly the most interesting one associated with this class of bodies, even more so than the nickeliferous iron. It has no representative in genus or species among terrestrial minerals, and is one possessed of highly interesting properties. Although among terrestrial minerals phosphates are found, not a single phosphuret is known to exist. So true is this that, with our present knowledge, if any one thing could convince me more strongly than another of the non-terrestrial origin of any natural body, it would be the presence of this or some similar phosphuret. It is commonly alluded to as a residue from the action of hydrochloric acid upon meteoric iron, when in fact it exists in plates and fragments of some size in almost all meteoric iron, and there is reason to believe that it is never absent from any of them in some form or other. What is meant by "some size" is that it is in pieces large enough to be seen by the naked eye, and to be detached mechanically.
In an examination of the meteoric specimens in the Yale College Cabinet more than half of them have been discovered to contain schreibersite, visible to the eye, that had been considered pyrites. Among them the large Texas meteorite was examined; and although none was visible on the surface,
a small fragment of the same mass given me by Prof. Silliman contains a piece of schreibersite of over a grain weight.
The reason why it has not attracted more attention arises from its resemblance to pyrites. I will therefore state a ready manner of telling whether it be such or not.
Detach a small fragment, and hold a magnet capable of sustaining five or six ounces or more within half an inch or an inch of the fragment. If it be schreibersite it will be attracted with great readiness, the magnetic pyrites requiring a very close approximation of the magnet before attracted. This, with some little experience, becomes a ready method of separating the two. It is not, however, to be expected that this method alone is to satisfy us when other means can be appealed to for distinguishing this mineral. The following is one which is readily accomplished with the smallest fragment (half a milligramme). Melt in a small loop of platinum wire a little carbonate of soda; add the smallest fragment of nitrate of soda and the piece of mineral; hold the mixture in the flame of a lamp for two or three minutes; place the bead of soda in a watch-glass; add a little water, and filter. To the filtrate add a drop or two of acid to neutralize the excess of carbonate of soda; evaporate nearly to dryness; add a drop of ammonia, and then a drop of ammoniacal sulphate of magnesia, when the double phosphate of magnesia and ammonia will show itself, and the crystalline form will be recognized under the microscope. If the piece examined be several milligrammes in weight, the operation can be carried on in a small platinum capsule. This reaction can also be had by acting on the mineral, however small the piece, by aqua regia; evaporate until only a little of the liquid is left; add a little tartaric acid, then a drop or two of ammonia to supersaturate the acid; and lastly a little ammoniacal sulphate of magnesia, when the crystals of the double phosphate of magnesia and ammonia will appear.
4. Protochloride of Iron.-In breaking open one of the fissures of this meteoric iron a small amount of a green substance was obtained that was easily soluble in water; and although not analyzed quantitively, it left no doubt upon my mind as to its being protochloride of iron; and the manner of its occurrence gave strong evidence of its being an original constituent of the mass, and not formed since the fall of the mass. Chloride