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:

"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.)

In water, 15 5 121
Its specific gravity is therefore

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

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 Aerolites.

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.

the earth's orbit, being now generally considered as the view which meets and explains most easily the peculiarities of their structure and appearance. For expositions of some of the various theories on these subjects, I need only refer to the well-known memoirs of Professors C. U. Shepard and J. L. Smith, M.D., of America,* and especially of Mr Robert Philips Greg,† of Manchester. M. Haidinger, director-general of the Geological Survey of Austria, has also published his views on the origin of aerolites, in a recent communication to the French Academy of Science.

Catalogues of Meteors and Meteorolites.—Catalogues detailing the particulars of all known meteors, aërolites, &c., have been from time to time published. I may refer to those given in the Reports of the British Association, and to the very complete list by Mr R. P. Greg in the Report of the year 1860.

Aerolites may be supposed to have fallen on our earth from the earliest periods of its history. I am not aware, however, of any instances that have been noticed connecting their existence with the earlier or geologic history of our globe. In the sacred Scriptures, such expressions as the great stones, and the hailstones, that were cast down from heaven, on the enemies of Israel, on the memorable occasion when an apparent interruption of the earth's motion took place (Joshua x. 11); and, again, the use of such terms, as coals of fire, in addition to the lightning, by the Psalmist, when speaking of the wonders of the Almighty (Ps. xviii. 12, 13), suggest, at least, the possibility of an allusion to these mysterious bodies. at that early period.

Meteoric Stones worshipped.-In the book of Acts (xix. 35) we have reference made to the image of the Diana of Ephesus, which fell down from Jupiter, undoubtedly an aërolite. The fall of one of these bodies among an ignorant and superstitious people, with its attendant phenomena of fire and explosion, would naturally be considered as a message from the gods, and especially from the presiding deity of the district. Various instances of falls of this kind are noticed by ancient authors, whose statements we have no reason altoEssay on Meteorites.

* American Journal of Science. VOL. II.

3 G

gether to disbelieve. We have also instances of the fall of aerolites recorded in our own day, being followed by similar results, as in a case noticed by the Rev. Baden Powell, M.A., &c., in his Report on Meteors to the British Association in 1859; of a stone-fall at Dooralla, near Loodianah, in 1815, when the natives worshipped it, and commenced subscriptions for erecting a temple over it. Two stones fell at Parnallee, near Madras, in 1857; and their fall was followed by exactly the same results-crowds of natives worshipping the larger stone, "as the image of their deity, which had fallen from heaven" (see Silliman's American Journal of Science, No. 32, Nov. 1861). One of these stones weighs 130 lbs., and is the largest meteoric stone known; it is now, I am glad to say, deposited in the British Museum.

There seems little doubt that meteoric falls were one, at least, of the causes of the stone-worship of the ancients, instances of which are represented on their coins, under canopies or shrines. The Diana of Ephesus is not represented in this way, although on an ancient medallion given as an illustration to a learned paper on the Coins of Ephesus,* by Mr J. Y. Akerman, and struck, he supposes, for those who came to wonder and to worship at her shrine, there is a rude mummy-like figure of the goddess, and on its head, if not simply an imperfect modius, with which she is often represented, something which reminds one of the very distinctive shape of a meteoric stone or aërolite.

Mr Akerman, in a paper on the Stone-Worship of the Ancients, illustrated by their Coins (Numismatic Journal, vol. ii. 1837-8), since pointed out to me by Mr G. Sim, also refers to the probability of aerolites being objects of worship.

Map of Meteoric Stone and Iron Falls.-The illustration of the subject of aerolites would be increased if, in addition to these published catalogues, we had also a map showing their fall over all the world. I would be especially anxious, in a map of this kind, that a careful distinction be made (by colour or otherwise) between metallic, and earthy or stone falls; a distinction which, it appears to me, has scarcely been kept sufficiently in view by some writers, when considering

* Numismatic Chronicle, vol iv. 1841, p. 118.