manifest; a little of the metal was then filed off, and put into the hands of Dr Murray Thomson, lecturer on Chemistry, without letting him know its history, and he informed me the filings consisted of iron, with a proportion of nickel. Native iron of terrestrial origin being almost chemically pure, and never containing any proportion of nickel, the mass of iron was therefore of meteoric origin, being an alloy of iron and nickel; the latter generally existing in very small proportion to the former.

The peculiar shape and appearance of this mass of metal itself, so entirely unlike any handiwork of man, was indeed almost proof enough to many of its meteoric character, of which, however, there was now no room for doubt.

The subsequent steps taken to learn the special peculiarities of its structure and chemical analysis have now to be detailed.

Section of Meteoric Iron.-The iron was cut longitudinally into two portions, by Mr Young, lapidary, as I was anxious to see whether any difference of structure existed in any part of the mass, or whether cavities containing olivine could be detected. Nothing of this kind, however, was disclosed, the mass being equally solid, dense, and steel-like in its appearance throughout, and the colour beautifully bright and white, like steel. With Mr Alexander Bryson's assistance, and a new steel file, I next proceeded to rub down as much of the surface of one of the pieces, as would suffice for a minutely detailed chemical analysis being made; and in assisting to do so, soon made a practical discovery of the extreme hardness or toughness of the metal, which in a comparatively short time turned the sharp points on the file itself. The hands soon became much blackened by the operation, as if plumbago was mixed with the iron. There seemed no doubt the metal was steel, from the carbon which was so manifestly present. The surface of the mass varied somewhat in its resistance to the file; its prism-like point was very close and hard externally, and contained apparently more of the blackening part of the iron; the upper and rounded portions were also hard and dense, at least externally, offering more resistance to the file; and the tool seemed to have less effect upon the iron when it was used across the mass, than in

its longest diameter. Its hardness, as shown by a graving tool, was greatest next its outer surface-the inner portions. being apparently softer, and more open in texture, while the prism-like point was tougher before the tool, and more like hammered iron; the explanation probably being-that this peculiarity was due to the shock of the fall being given principally to this part of the mass; and also, to its being suddenly cooled by the contact of its surface with the earth in which it was found buried.

The filings, of which about a troy ounce were procured, were black, and showed little of the shining metallic appearance of pure iron.

Chemical Analysis.-The filings were sent for examination to Dr Murray Thomson, who gives details of their composition in his subsequent communication. (See Analysis of Meteorolite, by Dr Murray Thomson.)

Test of Etching by Acid.-Each portion of the iron has been partially etched with the acid used by engravers on steel, which consists of equal parts of nitric and acetic acids; and the etched surfaces show the rough, irregular, projecting lines of the crystalline structure of the mass, which have been apparently but slightly acted on by the acid, from the presence of nickel; the dark lines and spaces showing where the acid has acted with greater effect. The acid was applied in the usual way for etching, and appeared to bite all at once, and that pretty deeply; it was then removed, the surface of the metal washed, and the acid reapplied, when it acted very slightly, and soon ceased to act altogether, not biting any deeper into the surface of the metal. The rough etched surface is characteristic of meteoric iron, various bright lines or points being observed in the fine frosted like appearance of the crystalline or fibrous surface of the metal. This etched surface is finer and more minute in its texture than that of any meteoric irons, the etchings of which I have been able to examine, suggesting a more minute subdivision of the particles of the iron and nickel, and a more general mixture of the nickel through the mass.*

*Mr R. P. Greg of Manchester informs me this minute texture resembles the structure of the iron also found in Britain, and described by him,-more

A steel-plate, treated in exactly a similar manner as this meteoric iron, was exhibited, and showed simply a regularly depressed smooth portion where the acid had been applied.

These etched patches, having been placed near the middle of each surface of the two portions of the meteorite, perhaps rather unfortunately, give to a careless observer the idea of the mass having a core or central part of a different structure; this appearance is of course due entirely to the action of the acid.

Printed Impression from Etched Surface.—I was anxious to learn if it would be possible to get a cast or squeeze in wax, taken from the etched surface, on each of the two portions into which the mass was cut, that it might be electrotyped, and the electrotype cast (which thus exactly corresponds to the original surface of the iron) backed up with metal in the usual way, so that impressions might be printed from it. The cast taken from the larger patch of etching was so large, and the raised markings so slightly defined in their character, that, when it was used as a woodcut, the printer could not prevent it getting blotted all over, when attempting to take an impression from its surface. The smaller etched patch, from its less size, and possibly slightly more defined markings, was found to answer better, and an impression of it is accordingly exhibited (see next page), which gives a fac simile of the etched surface and structure of the metal.

The cast has been printed from, in the same manner as a woodcut, and shows the projecting parts black, the light spaces between being the more deeply etched parts of the surface, and the smooth polished metal surrounding the whole, appearing like a black border. The white spots which cross the picture show traces of decay and the line of the fracture by which the mass became separated into two portions; for I was rather startled to learn that the process of taking the wax squeeze from the surface of the smaller portion of the meteorite with the ordinary printer's press, had broken it in two. It was evident, however, from the fractured surface, which was simply a weathered looking or oxidised continuation of the deep furrow which parthan any other meteoric iron known; only the minute markings of his specimen appeared to be more angular and sharp in character.

tially surrounded the mass, that this furrow had penetrated much deeper than was suspected, and that the few scattered dark spots, like corrosions on the polished surface of the sections, were the termination of the inner portions of this very furrow, part of the decay of which might be caused by the exposure and weathering the mass had undergone, in the fiveand-thirty years of its existence on the surface of the earth the origin of the furrow being due to the lobulated arrangement of the mass.

Weight and Specific Gravity of each of the Sections of the Meteorite.-Dr Murray Thomson has furnished me with the following notes of the weight and specific gravity of the different portions into which the meteorite is now divided:

66

"I. Of the halves into which the iron was cut, one was rather larger and heavier than the other, and weighs :In air, 18 lbs. 2 oz. 7 drs. (Avoir.)

"II. The smaller half, now broken into two portions,

weighs :

1. The larger or pointed portion,

In air, 7 lbs. 9 oz. 8 drs. (Avoir.)

2. The smaller rounded or lobed portion,

In air, 5 lbs. 10 oz. 2 drs. (Avoir.)

The difference in the specific gravity of the halves of the meteorite may probably be explained, by the presence, in the smaller portion of the mass, of the principal part of the large furrow already referred to-filled up with earthy-looking matter of lighter specific gravity.

*

In conclusion, I may add a few notes on the general subject of Meteorites or Aërolites.

Theories of the Source or Origin of Meteorites.-Various theories have been at different times brought forward to account for the presence of meteorites or aërolites, these strange and apparently accidental visitors.

These theories may be arranged in two great divisions:First, The terrestrial sources-the source or origin of these bodies being supposed to belong to our earth; and, secondly, The cosmical sources, which derive their origin from beyond our earth. These again may be each subdivided into two sections, or classes, as follows:

I. TERRESTRIAL SOURCES.

1. Volcanic-from the volcanoes of the earth.

2. Atmospheric-from their supposed formation in the atmosphere of our earth.

II. COSMICAL SOURCES.

1. Lunar Volcanic-from the volcanoes of the moon.
2. Interplanetary Space-the planetary or asteroidal
theory.

I shall not enter here into the arguments that have been brought forward both for and against these various theories, merely remarking that the old idea of their terrestrial origin is now almost entirely given up. The second of these divisions, and in particular that which derives their origin from a supposed belt of planetoids or asteroids revolving in space on the borders, or just beyond the most distant part (from the sun) of

* Dr Thomson afterwards examined some of this earthy-looking matter, and found it to consist of the same chemical components as the rest of the mass, the iron, however, being in the state of an oxide.