above that of the air in contact with it is greater in summer than in winter, as I have already shown in my memoir on the increase of nocturnal temperature with height.

Note to "Notice of a Mass of Meteoric Iron, found in the Village of Newstead, Roxburghshire." By JOHN ALEXANDER SMITH, M.D.*

Since this paper was read, the half of the Meteorite, which was broken into two portions, has been cut into several sections or slices; and in the process of doing so, it was found that the lobed or rounded portion was very hard and dense, resembling cast-iron in its character, it was harder than untempered steel of the best quality, but not so hard as the prepared steel plate of the engraver; while the pointed portion was softer and tougher, and was stated to resemble iron to which a small portion of malleable iron had been added. The slices showed that the mass was dense and metallic throughout, with the exception of a small part of the pointed portion, next the deep furrow which partially divided the mass (and by which. it became separated into two); the metal here was marked over with dull spots, like corrosions, and seemed less pure and crystalline, appearing as if mixed with dross. A portion of this latter part was given to Dr Murray Thomson to examine specially for the presence of magnetic oxide of iron; and Dr Thomson has accordingly added some notes on the subject to his previous communication.

The mass of iron was apparently not malleable, but brittle in its character. It would therefore, according to the classification proposed by Professor C. U. Shepard in his Report on Meteorites, belong to the 2d SECTION-Alloyed, of the 3d ORDER-Brittle, of his 1st CLASS-METALLIC METEORITES. (See "Silliman's American Journal" for 1846 and 1847.)

An opportunity was also taken of repeating, on one of the polished slices, the etching with acid, to see if it was possible. to get a more distinct display of its peculiar crystalline structure, by watching the action of the acid on the metal. In place of using the mixed nitric and glacial acetic acids of the steel * Vide Journal, vol. xvi. July 1862, p. 108.

engraver, as was formerly done, nitric acid alone was used; but little or no effect was produced, with the exception of a very slight etching on the part first touched. The nitric acid was then diluted with about an equal quantity of water, and on its being again applied to the metal a rapid action took place, with a considerable evolution of gas, and a brownish or darkcoloured matter (carbonaceous ?) was seen to rise and mix with the acid solution, not from the coating protecting the rest of the metal, but from the bitten surface of the metal itself. The presence of this brown-coloured matter is stated not to be observed when ordinary steel is etched. Instead of making, as before, a large etched patch at the line of separation or fracture of the rounded and pointed portions of the mass of iron, a small patch was etched near the middle of the rounded

or lobed portion (fig. 1), and this displays very distinctly the characteristic and beautiful frosted-like lines of crystallization, crossing one another at various angles. As formerly stated, these lines are finer, or more minute, than in many meteoric irons. This finer texture seems to be also present in other brittle irons; at least it is mentioned as occurring in those described by Professor Shepard in his Report. (See "Silliman's American Journal," 1847.) I am inclined to think it not improbable that this fine, or less-distinctly marked texture may be simply dependent on the rapid cooling, or any other cause which gives the iron its brittle character. Another patch of etching was made near the narrow extremity of the pointed portion of the mass (fig. 2). Here the crystalline structure of crossing lines is less distinct, the metal being apparently

more granular in its texture, and exhibiting a series of shining points. The action of the diluted acid on the metal was closely watched, and was stopped occasionally, so as to preserve the appearance of the etching, when its character was most distinct. Wax squeezes and electrotype casts were taken from these etched surfaces, and are here printed from as woodcuts (figs. 1, 2). They may therefore be compared with that figured before, which was taken in a similar way from the central part of the meteoric iron.

A portion of this meteoric iron, with plaster cast of the entire mass, are now preserved in the Natural History Museum, Edinburgh; the principal part of the iron is in the British Museum, London.

Note to "Analysis of the Meteorite described by Dr John Alexander Smith, M.D." By MURRAY THOMSON, M.D., F.C.S., Lecturer on Chemistry.*

As formerly stated, the specific gravity of the meteorite, in its entire or undivided state, was 6.517. From an unfortunate inadvertence, however, some of the details of the weights and specific gravities of the divided portions of this meteoric iron were incorrectly printed in the communications published in this Journal in July last. It will therefore be necessary to substitute, for those formerly given in Dr Smith's paper (p. 118), and in my analysis (page 125), the following correct table of the different weights and specific gravities :

1. 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 12

Its specific gravity is therefore

6.499

II. The smaller half, now broken into two portions, weighs:

1. The larger or pointed portion,

In air, 7 lbs. 9 oz. 84 drs. (Avoir.)

In water, 6 7 8

Specific gravity,

* Vide Journal, vol. xvi., July 1862, p. 125.

6.7400

2. The smaller or rounded portion:

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

In water, 4

Specific gravity,

11, 91

6.1919

After the communication on the Analysis was written, and as a portion of the mass had been cut into pieces of various sizes, another opportunity was had of taking the specific gravity of a slice (separated into two portions), embracing the whole thickness of the mass. These pieces being more manageable for the purpose of taking density, it is to be presumed that the following numbers express, with the utmost accuracy, their specific gravity:

Slice from the pyramidal or pointed portion gave, 6.750 sp. gr.

It was also noticed, in examining a small portion of the first of these slices, where the metal was corroded-looking, and showed various black spots on its surface, that this iron was very brittle; so much so, that no difficulty was experienced in reducing a fragment of it to powder in an iron mortar.

I would likewise here record, that a further chemical examination was made, chiefly in search of magnetic oxide of iron, which is so frequently a constituent of meteorites, but, as before, I could obtain no evidence of the existence of this substance.

It has been already stated that the portion of the meteorite used for analysis was that obtained by filing the exposed faces of its halves; it might therefore be objected, that the material so procured, at least from the harder portion, was likely to be mixed with particles of the file used, and especially that the percentage of the carbon in the meteorite might thereby come out too high. It certainly cannot be denied. that minute particles of the substance of the file would mix with the filings; but from the texture of the mass these must have been but a very trifling proportion, compared to the bulk of the filings. To be certain, however, that no substantial error had crept in from this source, another determination of the carbon and silica was made on a solid piece of the meteorite, the result being to show the presence of these constituents in the following proportions:

Carbon,

Silica, .

0.56 per cent.

0.90 ""

These new percentages being so close to the last, we may regard the first analysis as quite correct.]

Address delivered at the Opening of the Session of the Royal Society of Edinburgh, on Monday, 1st December 1862, by Principal FORBES, D.C.L., F.R.S., Vice-President of the Society.

GENTLEMEN,I propose to address you on this occasion with reference to the following points :

First, to recapitulate briefly the origin, the objects, and the Constitution of Societies similar to our own.

Secondly, to trace the rise and general history of the Royal Society of Edinburgh.

Thirdly, to consider what changes the progress of science and of society render necessary or desirable in the working of associations like ours, and how far such changes are safe and prudent.

Lastly, to recall the history of this Society during the past twelve months, especially with reference to the Fellows whom it has

lost.

I. To recapitulate briefly the Origin, Objects, and Constitution of

Societies similar to our own.

Societies having any true analogy to the academies of modern Europe, or to the Royal Societies of London and Edinburgh, or the Royal Irish Academy, have arisen within about 300 years. Italy was their birth-place, and perhaps, on the whole, in no country have they flourished more. They appear to have been the direct offspring of the spirit of inquiry so active in that country throughout the sixteenth and seventeenth centuries. According to the literary historians of Italy, the cultivation of literature by academicians, salaried by the Government, commenced at Rome in 1514, under the Pontificate of Leo X. It is well known, that the cultivation of literature and the fine arts continued to be fostered in Italy by similar institutions during many generations. The Accademia della Crusca (named after the Italian word for bran or chaff, from the fanciful analogy of sifting the pure from the heterogeneous