tions relate principally to the structure of the liver and its ducts, the testicles, and the brain. With respect to this latter organ, Sir Everard observes, as the point most deserving of attention, that the proportion of the cerebellum to the tubercula quadrigemina is greater than in other species of this genus. An ample description is given of the eye, which is small for the size of the animal. With respect to the ear, the most remarkable circumstance is the great capacity of the cavity in which the semi-circular canals are contained. The branchial artery is furnished with a very conspicuous muscular structure; and it is conjectured that this may be necessary to accelerate the circulation through the part, when the fish is at a great depth below the surface, and consequently exposed to a proportionable degree of pressure: My former account,' says Sir Everard, was taken from a Squalus Maximus caught at Hastings, in November 1808, and the parts which I examined were brought to London by Mr. Clift, who went down, at my desire, to dissect them; but the weather being stormy and cold, the fish was brought no further than the beach, so that the examination was conducted under great disadvantages, and the parts brought away were in a mutilated state. The sketch of the fish made upon the spot by Mr. Clift is now found to be generally correct, except the omission of a small fin between the anus and tail, which had been buried by the weight of the fish in the sand. The omission of this small fin in the drawing is an error of considerable importance, as it deprived the fish of one of its characteristic marks, and has led naturalists, who have since had the opportunity of examining other specimens with more accuracy, to conclude that this fish was a distinct species from those which they described; I am therefore particularly desirous to correct the mistake.' Some farther Observations on a new Detonating Substance. By Sir H. Ďavy, LL.D., F.R.S., &c. &c.-This ingenious chemist here details a number of additional experiments, which he performed with his accustomed dexterity and address on the newly discovered detonating compound, of which an account was given in the former part of these Transactions. (See our last Number, p. 69.) Notwithstanding the dangerous nature of the process, and the risks which he had already run in the attempt, he again endeavoured to decompose the substance, so as to ascertain the nature and proportion of its ingredients. By carefully introducing it into a tube of mercury, he succeeded in procuring an oxymuriate of mercury, with a residue of azot; and, from the quantity obtained, he concludes that the composition of the substance in question is about 51 parts by weight of azot, and 643 parts of dry oxymuriatic acid, or chlorine; or in volume about 19 to 81: though, from the nature of the process, he thinks it is probable that the estimate REV. JUNE, 1814. M of of the proportion of azot may be too small. In reasoning on the nature and constitution of this body, Sir Humphrey proceeds on the peculiar view which he takes of the nature of the oxymuriatic and muriatic acids: but we cannot perceive that any circumstance is connected with this new substance which gives additional force to the hypothesis. Perhaps the subsequent remarks may be regarded as rather adverse to it: The results of the analysis of the new compound are interesting for several reasons. They shew, what seemed probable from other facts, that there is no strict law of analogy, which regulates the combinations of the same substance with different substances. As three of hydrogen combine with one of azote, and one of hydrogen with one of chlorine, I thought it probable that the new compound would contain three of chlorine to one of azote, which is not the case. This compound is the first instance known of one proportion of a substance uniting to four proportions of another substance, without some intermediate compound of 1 and 1, 1 and 2, and 1 and 3; and the fact should render us cautious in adopting hypothetical views of the composition of bodies from the relations of the quantities in which they combine. Those who argue that there must be one proportion of oxygen in azote, because there ought to be six proportions in nitric acid, instead of five, which are produced from it by analysis, might with full as much propriety contend, that there must be azote in chlorine in some simple multiple of that existing in the compound.' Experiments on the Production of Cold by the Evaporation of the Sulphuret of Carbon. By Alex. Marcet, M.D., F.R.S., &c. -The author of this paper, who is so well known for the accuracy and nicety of his chemical operations, here reports number of interesting experiments which he performed with the sulphuret of carbon, on the production of artificial cold. By covering the substance, on which the experiment is to be made, with a porous body, moistening this latter with the sulphuret, and promoting the evaporation by the action of the air-pump, a cold of -80° may be easily obtained. On a Saline Substance from Mount Vesuvius. By James Smithson, Esq., F.R.S.- Mr. Smithson supposes that many natural phænomena indicate that the earth was once in a state of general conflagration; and that a kind of stony crust or envelope was produced by this process, under which is contained a large mass of combustible matter, which still continually bursts forth in volcanic eruptions. After this preliminary observation, he proceeds to the analysis of a saline body which was ejected from Vesuvius; and which was found to consist principally of the sulphat of potash, mixed with the sulphat of soda, together with minute portions of the muriat of soda and the muriat of copper. The saline mass was mixed with a quantity of insoluble matter, which was principally the ore of iron. Some Experiments and Observations on the Substances produced in different Chemical Processes on Fluor Spar. By Sir H. Davy, LL.D., F.R.S., &c. - Sir Humphrey remarks that, when potassium is burnt in silicated fluoric acid-gas, the gas is absorbed, and a substance is produced which, when heated in oxygen, reproduces the silicated fluoric acid. He at first supposed that the acid was deoxidated in this process: but he was subsequently led to believe that it was analogous in its nature to the muriatic acid, which, according to the new hypothesis, consists of a peculiar substance united to hydrogen. The fluoric acid enters into three substances which have been the subject of much interesting investigation: viz. silicated fluoric acid-gas, liquid fluoric acid, and fluo-boric acid-gas; and it is observed that three hypotheses may be formed respecting the nature of the fluoric compounds. In the first, which is that generally adopted, the silicated fluoric acid gas is supposed to be a compound of silica and a peculiar acid, itself consisting of inflammable matter and oxygen; fluo-boric acid gas, a compound of boracic acid and the same acid; and pure liquid fluoric acid as water combined with the acid. In the second hypothesis, that which I have alluded to in the beginning of this paper, and that adopted by M. Ampere, the silicated fluoric acid is conceived to consist of a peculiar undecompounded principle, analogous to chlorine and oxygen, united to the basis of silica, or silicum; the fluo-boric acid of the same principle united to boron; and the pure liquid fluoric acid as this principle united to hydrogen. In the third hypothesis, which probably would have been formed by the disciples of the phlogistic school of chemistry, had they been acquainted with the facts, the liquid fluoric acid is considered as an undecompounded body; and the metals and inflammable bodies as compounds of certain unknown bases with hydrogen: silicated fluoric acid gas, on this idea, must be regarded as a compound of the fluoric acid with the basis of silicum, and fluo-boric acid gas as a compound of fluoric acid and the basis of boron.' The author confesses that it is difficult to devise any simple experiments which may positively decide on the truth of these hypotheses: but he thinks that, by adopting analogical reasoning, we may discover which of them is most conformable to other chemical facts. Some experiments are then adduced to shew that fluoric acid does not contain either water or oxygen; and the effects of electricity on fluoric acid are related: all which circumstances are supposed to be most in favour of the second of the three hypotheses stated above. Sir H. afterward relates a number of experiments which he performed with the A 2 intention intention of procuring the fluoric acid in a pure or uncombined state, but without success. The following is the inference which he draws on this subject: From the general tenor of the results that I have stated, it appears reasonable to conclude that there exists in the fluoric compounds a peculiar substance, possessed of strong attractions for metallic bodies and hydrogen, and which combined with certain inflammable bodies forms peculiar acids, and which, in consequence of its strong affinities and high decomposing agencies, it will be very diffi. cult to examine in a pure form, and, for the sake of avoiding circumlocution, it may be denominated fluorine, a name suggested to me by M. Ampere.' The volume closes with the usual list of presents received by the Society, and with an Index. ART. VI. Sicily and its Inhabitants. Observations made during a Residence in that Country, in the Years 1809 and 1810. By W. H. Thompson, Esq. 4to. Pp. 234. with Plates and a Map of Sicily. l. 11s. 6d. Boards. Colburn. 1813. WE Ewere recently called, in the case of Mr. Blaquiere, to report the work of a writer who laboured to exhibit, in a connected shape, a variety of miscellaneous information with respect to Sicily and the coast of Barbary *; and we come now to render an account of another production suggested by the same fertile topic, but comparatively limited in its extent, Mr. Thompson not having aimed at going beyond the boundaries of Sicily, and professing to give rather an illustration of particular topics than to attempt comprehensive descriptions. In point of political feeling, he is as ardent an advocate as Mr. Leckie, or Mr. Blaquiere, for British interference in the affairs of Sicily. He speaks with partiality of the royal family, but believes that we might be instrumental in introducing improvements of great importance, without deviating from the pledge formerly given, of holding the island for its lawful sovereign, and not for ourselves. Every person, he says, on visiting Sicily, must exclaim that nature has done every thing for it; art, nothing. Almost all the articles, for which we are at present dependent on a precarious intercourse with Italy, might be supplied by this fertile island, if it were under a different system of cultivation. Mr. Thompson's object has accordingly been to urge the public to consider how greatly England is interested in the preservation of Sicily, and of how * See Review for January last. much much consequence it was that the French should not obtain possession of it. With all his sollicitude, however, for the retention of Sicily, Mr. T. has no hesitation in acknowleging that to render that island productive will be the work of much time and labour. It is yet so unimproved as to have no roads farther than forty miles from Palermo; beyond that limit, nothing but tracks occur, which it is impossible to discern without a guide who is well acquainted with the country. They are not practicable for carts, and the conveyance of corn or merchandise can therefore take place only on the backs of mules. With regard to the oppressive corn-laws, and the tyrannical ascendancy of the nobility, Mr. Thompson confirms the observations which we extracted, several years ago, from the crude but useful publication of Mr. Leckie *. Nothing,' he admits, is seen in Sicily but misery and oppression on all sides, and a government sunk into the last stage of weakness.' As long as Naples remained to the present king of Sicily, his ministers had no other policy respecting that island than to keep it in complete submission to their continental territory; and, in the execution of this policy, they appear to have followed a course nearly as mild and liberal as that of our government of former days with respect to Ireland. Mr. Thompson is much fonder of distributing praise than censure. He passes over, with a gentle hand, the wretched education of the Sicilian nobles, and takes pleasure in vindi-' cating the behaviour of the fair sex. I confess,' he says, 'I have acquired a considerable degree of regard for the Sicilians: I found them to possess many amiable qualities. I went amongst them as a stranger, without any particular recommendation except that of being an Englishman: but this was sufficient. I found many of them men possessing the most refined manners, endowed by nature with excellent natural abilities; though I must confess their education is not always attended to sufficiently. I found the women amiable and unaffected; and, notwithstanding general opinion originating from the freedom of manners allowed, many of them virtuous, affectionate, and well informed, their education being more attended to than that of the men. I do not mean to affirm that this is always the case. I well know it is not; but one must not, from particular examples of vice and immorality, censure a whole people; and at all events I shall be happy if I can, in any degree, remove a very common, though erroneous opi nion, that the freedom of manners abroad, which an Englishman is not accustomed to at home, is the consequence of confirmed vicious habits and that, because the customs of a country are different M. R. Vol. lix. p. 283. from |