Imágenes de páginas
PDF
EPUB

tion of acids. The etched surface is illustrated in the accompanying figure. The pattern is strikingly peculiar, as well as beautiful. The bright shining veins, which resist the action of the acid, are rarely nearer together than the 'th or 'th of an inch;

[merged small][graphic]

and these in place of being continuous, are interrupted at frequent intervals. In their course also, they frequently exhibit little triangular enlargements, the sides of the triangles curving inwards. The surface included between the shining lines, and which forms at least ths of the whole, is every where finely freckled as if depending upon a granular texture, and even bears some analogy to what is familiarly known as crystallized tin, or Moiree metallique.

Its hardness is very unusual, no iron with which I am acquainted offering on the whole, so much resistance to the operation of slitting. Mr. Rockwell gives as its composition, iron 92-291, and nickel 8.146. My own result in a single analysis, is as follows:

[blocks in formation]

Sub-section, COARSELY CRYSTAlline.

9. De Kalb county, Tennessee.-Vol. xlix, p. 341, (1845.) 10. Asheville, (Baird's plantation, near French Broad River, six miles north of Asheville,) Buncombe county, North Carolina. -Vol. xxxvi, p. 81, (1839,) and Die Meteoriten, von P. PARTSCH, Wien, 1843, s. 116.

As this county has of late afforded two other localities of meteoric iron, I have taken pains to ascertain as nearly as possible the exact position of each. The Hon. T. J. Clingman informs me, that this locality is six miles north of Asheville, on the estate of Col. Baird, who is of opinion that other fragments may there be found, as he has within two years observed small pieces of rusty iron in the same field from which Dr. Hardy's mass was obtained.

Farther experiments on the composition of this iron, enable me to add to what was before made known, that it contains cobalt, magnesium and phosphorus; and that the nickel is sometimes present in a ratio as high as 5 p. c., while the silicon is considerably below 0.5 p. c., as formerly quoted.

11. Guildford county, North Carolina.-Vol. xl, p. 369, (1841,) and Die Meteoriten, von P. PARTSCH, S. 114.

12. Carthage, Tennessee.-Vol. ii, ii Ser., p. 356, (1846.) 13. Jackson county, Tennessee.-Vol. ii, ii Šer., p. 357, (1846.) ORDER SECOND. Malleable, heterogeneous.

Section 1st. AMYGDALOIDAL.*

14. Hommoney Creek, near base of Pisgah Mountain, (ten miles west of Asheville,) Buncombe county, North Carolina.

The present iron was brought to light through the perseverance of the Hon. T. J. CLINGMAN, of Asheville, to whose liberality I am indebted also for the possession of so interesting an object. He informed me in March, 1846, that while in the adjoining county of Haywood, he had accidentally been told by a Mr. Clarke, that his son had a mass of ore, five or six pounds in weight, that was very black and heavy, and which they could not break with a sledge-hammer, though they were able to indent its surface. Mr. C. was disappointed, on visiting the son, to find the piece had been mislaid and probably lost. His description however, agreed closely with that given by the father. He learned also from the young man, that the mass had the appearance of

The present mass having been discovered since the classification of the previous paper was made, it becomes necessary to create a new section for the reception of this remarkable variety. In some respects, it resembles the amygdalo-peridotic species from Siberia and Atacama. It differs however, from them both, in the more diminutive cavities, and still more in this, that these cavities are almost completely empty. The term amygdaloidal therefore, is here applied, in analogy with its use in geology, for describing the vesicular traps.

having been melted, one side being flattened, while from other parts of it, there were projections ("spurs") as long as a man's finger, which he could batter down with a stroke of the hammer. He said he obtained it a year before in Buncombe county, in a field, where he was of opinion that more of the same might be found. Mr. C. afterwards visited the neighborhood in which the specimen occurred; and was there assured by a young man, that he had seen the piece that the Clarkes had described, and that he knew of another much larger piece, similar to it, at an old house on the Clarke farm, where the smaller had been found.

On procuring the mass, (which weighed nearly twenty-seven pounds,) Mr. C. communicated to me the following particulars respecting it, which may perhaps be given in this place as generally descriptive of its aspect. "It is rather flat on one side, as though it had been laid when semi-fluid on a somewhat plane surface, while its other sides are irregular, with cavities and various inequalities. It has no appearance of ever having been hammered, and externally looks like a cinder from a blacksmith's fire." (At first, from not having seen any vesicular meteoric iron, Mr. C. was led to question its genuineness.) "But

it is too large, and much too heavy to be compared with cinder. It has some malleability, though it may be broken if struck on its thinner projections and edges. Its knotted appearance, toughness and malleability, together with the peculiar form of the broad side, or bottom, and that of the large end, indicating that a greater than human force must have been applied to the mass, and evincing that it was cleft by an explosion from some large body, lead me on the whole, to rest in the inference, that it is of foreign origin." Mr. C. likewise remarked, that its external appearance would be well conceived of, if we supposed an ordinary mass of meteoric iron to be thrown into a forge-fire, and when thoroughly fused at its surface, suddenly to be withdrawn and cooled.

Its shape may be judged of by the figure on the opposite page. As frequently happens with these productions, a general conception may best be obtained by likening them to some familiar objects: this specimen strikingly reminds one of the head of a reptile. As figured, it reposes on its flat and broad side, and the dark shadow at the left, is in the place of the nearly vertical section, supposed to represent the junction of the animal's head with its body. It measures eleven inches in length, by seven in breadth; and is four in thickness at the thicker end, while at the upper extremity of our figure, it is not above two and a half, and on the right and lower edge, it thins down to little above one inch. Its surface is rather tuberose and jagged, than pitted with regular depressions. Color various shades of brown to black, and somewhat variegated (especially in the bottoms of the cavities) with

an ash colored earthy matter. This last was undoubtedly derived from the circumstance, that the mass was for a considerable time employed as a support for fuel in the fireplace of a farmer's kitchen. Upon the under side, there adheres over a few inches,

[merged small][graphic]

But

a crust of an earthy, black amygdaloid, scarcely distinguishable, unless freshly broken, from the iron itself; and in one spot, nearly buried within the substance of the iron, a few grains of a dull, yellowish, gray olivine were noticed, similar to those found in the Bitburg iron. Near the surface, and especially upon the thinner edge and at the small extremity of the mass, its structure is eminently vesicular, the cavities being from one-fourth to onetwentieth of an inch in diameter, sometimes distinct, at others running together, and generally lined with a black powder. as the distance increases to an inch from the surface, the cavities grow smaller and more remote from one another. No deeper section than one inch has yet been made in the mass; it is therefore possible, that the central portions may be nearly compact. The fresh fracture has a color and lustre, intermediate between steel and magnetic iron-pyrites. Etched surfaces, excepting where the structure is highly vesicular, exhibit the most delicate Widmannstättian figures, consisting of very minute and thickly SECOND SERIES, Vol. IV, No. 10.-July, 1847.

11

interspersed triangular figures, distinct enough to be easily seen with the naked eye, but under a microscope exceedingly beautiful. They resemble somewhat in this respect, the Bitburg iron, to which it also approximates in the tuberose conformation of the exterior surface.

Hardness about that of grey cast iron.

It is composed of iron, (with traces >
of chromium and cobalt,)

Nickel,

Sp. gr. 7-32.

Carbonaceous, insoluble matter and loss,

[ocr errors]

98-19

0.23

1.58

100.00

The yellowish, olivine-like grains consist of silicic acid, lime, magnesia, and oxyd of iron.

[blocks in formation]

15. Lockport, (Cambria,) New York.-Vol. xlviii, p. 388, (1845.) Vol. ii, i Ser., p. 374, (1846.) In addition to the nickel, copper, phosphorus and silicon, found in this iron by others, I have detected cobalt.

[blocks in formation]

16. Black Mountain, head of Swannanoah River, eastern line of Buncombe county, (fifteen miles east of Asheville,) N. C.— My first knowledge of this iron was derived from a remark, contained in a letter from Hon. T. J. CLINGMAN, dated Feb. 17, 1846, to the following effect: "Dr. Hardy informs me that he gave a very remarkable looking specimen of meteoric iron found in this county, (Buncombe,) to the late Col. Nicholson of Charleston, S. C., who died at Abbeville in that state, six or seven years ago." Being in Charleston, I applied to the executors of Col. N. for information respecting that portion of his effects, which would be likely to include this specimen; but my inquiries were without success. Previous to this date however, I had been informed by Prof. Tuomey, who was then the state geologist, that he had seen a specimen of malleable iron in the cabinet of Dr. BARRATT of Abbeville, which led me to address a letter to this gentleman, relative to the subject, from whom I received the following note, dated June 1, 1846, accompanied by the specimen itself. "I can furnish you with little that is definite concerning its history. The year Col. Nicholson, of Charleston, died, he had obtained it in Pendleton or Greenville District. It was given to him by some person, who had picked it up as a meteorite. Col. N. gave it to me, as I was the only person in this part of the country who preserved such objects. I believe it to be meteoric in its origin, and as such it has had a place in my cabinet. To yourself and to science, it is most cheerfully tendered."

« AnteriorContinuar »