nately scattered and equally broken with the bones of other animals in the cave of Kirkdale, were reduced to this state by the agency of the surviving individuals of their own species.

A large proportion of the hyænas' teeth bear marks of extreme old age, some being abraded to the very sockets, and the majority having lost the upper portion of their coronary part, and having fangs extremely large: these probably died in the den from mere old age: and if we compare the lacerated condition of the bones that accompany them, with the state of the teeth thus worn down to the very stumps, notwithstanding their prodigious strength, we find in the latter the obvious instruments by which the former were thus comminuted. A great number of other teeth appear to have belonged to young hyænas, for the fangs are not developed, and the points and edges of the crown are not the least worn down. I have a fragment of the jaw of an hyæna which died so young, that the second set of its teeth had not been protruded, but were in the act of forming within the jaw. Others are in various stages of advancement towards maturity; and the proportion of these is too great for us to attribute them to animals that may have died in early life from accident or disease. It seems more probable, and the idea is confirmed by the above statement of Mr. Brown, and by the fact of the hyænas' bones in the den being gnawed and broken to pieces equally with the rest, that they were occasionally killed and devoured by the stronger individuals of their own species.

But besides the evidence their teeth afford to show that the animals died at various periods of life, they present other appearances (and so likewise do the bones), of having passed through different stages and gradations of decay, arising from the different length of time they had lain exposed in the bottom of the den, before the muddy sediment entered, which, since its introduction, has preserved them from further decomposition. This observation applies equally to all the animals. I have portions of bone and teeth that are so much decomposed as to be ready to fall to pieces by the slightest touch; these had probably lain a long time unprotected in the bottom of the den; others still older may have entirely perished; but the majority both of teeth and fragments of bone are in a state of the highest preservation; and many thousands have been collected and carried away since the cave was discovered. In all cases the degree of decay is equal in the teeth and jaw bones, or fragments of jaws, to which they are attached.

ARTICLE VIII.

On Diaspore. By J. G. Children, Esq. FRS. &c.

(To the Editor of the Annals of Philosophy.)

DEAR SIR,

British Museum, July 24, 1822.

IN the third volume (New Series) of the Annals of Philosophy, p. 433, Mr. G. B. Sowerby has published his discovery of a new variety of Diaspore, together with some experiments which I made, at his desire, on a portion of it by the blowpipe, and in the following volume, p. 17, your brother, Mr. W. Phillips, with his usual ability, has described the crystalline form of a similar substance in the possession of Mr. S. L. Kent, a fragment of which I have also examined, and am satisfied of its identity with the former.

I have subsequently submitted the mineral to a further analysis, and, I believe, the results as stated below, are a pretty near approximation to the truth, though the quantity on which I operated was necessarily small, notwithstanding Mr. Sowerby's liberality, who would willingly have furnished me with larger portions of this very rare substance, had I thought it right to consent to the sacrifice!

The quantity of water was ascertained by heating the mineral to redness, in which operation pure water only was given off. The heated portion was fused with about eight times its weight of borax, the mass dissolved in diluted muriatic acid, and the whole precipitated by carbonate of potassa. The precipitate, well washed, was collected from the filter while in a moist state, and treated with a solution of pure potassa, which left the oxide of iron untouched; and, lastly, the alumina was separated from the alkali by muriate of ammonia.

The use of borax for the fusion of aluminous stones was, I believe, first recommended by Mr. Chenevix, and is the best flux for such minerals that I am acquainted with; but in the subsequent precipitation of the alumina from its solution in the muriatic acid, by carbonate of potassa, it is necessary to concentrate the solution by evaporation (for the glass requires a rather large quantity of fluid to dissolve it), or a considerable proportion will escape the action of the precipitant, even though boiled. I was nearly led into a serious error by not being aware of this circumstance.

It is stated, in Mr. Sowerby's communication, that the test of boracic acid and iron before the blowpipe gave no trace of the presence of a phosphate in the mineral; and I equally failed in detecting any, by treating a small portion with soda and silica, in

the manner used by Berzelius in his excellent analysis of Wavellite. I also made a separate experiment to ascertain if the diaspore contain an alkali, by fusing it with nitrate of baryta, but of this also I could discover no trace. The result of my analysis conducted as above gave

Lelievre's diaspore is accompanied by a dark coloured substance, which has been supposed to be a mere variety of the lighter, but by the following experiment, on a minute portion furnished by Mr. Sowerby, before the blowpipe, that does not appear to be the case.

In the matrass, if freed from the true diaspore, the assay does not decrepitate. Its dark brown (almost black) colour becomes rather lighter, and it gives off a large quantity of water. Alone in the forceps it does not fuse. The heated fragment does not brown moistened turmeric paper.

With soda, on platina wire, in the oxidating flame, it gives a light opaque dirty brown globule. In the reducing flame, the colour is darker, and somewhat inclining to bottle-green.

On platina foil, with soda and nitre, it gives no trace of man

ganese.

With borax, on platina wire, in the oxidating flame, fuses slowly into a perfectly transparent glass, deep orange-red while hot, fine yellow when cold, and which does not become opaque by flaming. In the reducing flame, the colour of the globule changes to bottle-green.

With salt of phosphorus, on the platina wire, in the oxidating flame, it dissolves slowly, but perfectly, into a diaphanous glass of a fine deep orange colour while hot, which, on cooling, becomes lemon-yellow, and when quite cold is colourless. In the reducing flame the assay presents the same phenomena.

A portion of the pulverised assay treated with a drop of nitrate of cobalt on charcoal, in the usual manner, gave a black

mass.

Vauquelin's analysis of Lelievre's diaspore gave

Memoirs of the Astronomical Society of London. Vol. I.

London. 1822.

THOSE anticipations in which we ventured to indulge, when announcing the formation of the Astronomical Society, the contents of the present volume have fully justified. The list of its members comprehending names unquestionably the most distinguished among the scientific, and the well-known zeal of many in the practice of astronomy, gave assurance that numerous valuable communications would soon be presented to it. From the distinction which has been acquired by the artists of this country in the construction of astronomical instruments, it might naturally be expected that practical contributions of this description would frequently appear; and accordingly among these memoirs, the first and second convey the results of the ingenious labours of Troughton and Dollond; the former giving "an account of the repeating circle, and of the altitude and azimuth instrument; describing their different constructions, the manner of performing their principal adjustments, and how to make observations with them, together with a comparison of their respective advantages ;" and the latter offering "the description of a repeating instrument upon a new construction."

He

That the repeating circle, introduced for the correction of imperfections in the art of dividing, should not be approved by Mr. Troughton, who has so greatly advanced that art, and still so actively labours to perfect it, cannot occasion any surprize. Even its form and general appearance are objected to by him, for it is stated to be "of all the instruments subservient to geodesy and astronomy, the most uncouth and unsightly." adds, "the whole of the effective parts are placed on one side of its single supporting pillar, and on the other a weight almost equal to the instrument, is placed for the purpose of keeping it in equilibrio. But ugliness is not the worst thing that attends this unavoidable combination; for it renders the instrument top-heavy, tottering, and weak. In these respects, the azimuth

circle is very much superior. The whole of its fabric is regular and self-balanced; the upper circle being supported like a transit upon two columns is thus rendered firm and steady. Respecting sightliness, I think the man of taste would, in the different forms it has appeared under, pronounce it agreeable, I dare not say beautiful; and here I may be allowed to remark, that the art of instrument making, as a matter of taste, is far behind many others. In this country indeed at the beginning of the art, instruments were adorned with the flourish of the engraver, chaser, and carver (now long out of fashion); but these are not the beauties which I mean; those of uniformity of figure and just proportions are alone what I have in view; and I cannot for a moment think that these are at all inconsistent either with strength or accuracy. Through the whole of this paper, every reader will have seen that I am an advocate for the altitude and azimuth instrument, and I have made no endeavour to conceal it; yet if I have said more for it than it deserves, or given to the repeating circle less than its due, it is a thing I am quite unconscious of." How different is the opinion of the celebrated Biot respecting this degraded instrument, the following quotation from the Traité Elementaire d'Astronomie Physique will show: "L'erreur des divisions est donc comme nulle dans les observations faites au cercle. Il est impossible qu'elle soit aussi rigourousement detruite dans les plus grands instrumens s'ils ne sont pas répétiteurs. Jamais l'addresse de l'artiste ne peut égaler un procédé mathematique." (Tome 1, chap. xx. p. 278, Edit. Seconde.) Should Mr. Troughton candidly and attentively peruse the elaborate disquisition, entitled, "Description et Usages du Cercle repetiteur," he may be induced to discard the predictions which he has advanced in the concluding paragraphs of his essay. "As it was the rudeness and inaccuracy of dividing which brought this instrument into existence, we should think that as the art becomes cultivated, it will fall into disuse. The art in this country is sufficiently advanced to set repeating instruments aside; and if I am rightly informed, several foreign artists are at this time pursuing the course of its improvement, in which they had for many years been impeded by circumstances which science could not controul. It is, therefore, my opinion, that as the division of instruments becomes generally improved, so will the repeating circle hasten to its dissolution; and, perhaps, on account of the great services which in its time it has rendered to astronomy and geodesy, some future age may be induced to chaunt its requiem."

The repeating instrument, of which the construction is described in the second memoir, was finished in Jan. 1819, and is stated by Mr. Dollond to be applicable to all the uses where vertical and horizontal angles are required to be taken. It may be sufficient for our present purpose to point out the novelties by which it is distinguished. The first novelty is the transverse or transit