present 800 leagues from the river Senegal to the Nile, on which scarcely an European has trodden, and of which our knowlege is extremely imperfect *, The present memoir is divided into two parts. In the first, the author endeavours to prove that the course of the Niger or Senegal is from the eastern parts of Africa to the western; in the second, he treats of the Interior of Africa, and points out the means of exploring it, and even of traversing it from the mouth of the Senegal to the Red Sea. We must forbear, on account of want of room, to quote the various and important authorities adduced by M. DE LA LANDE in support of his opinion. What he has done will no doubt an swer the end proposed by him, viz. that of exciting curiosity and the spirit of enterprise, by shewing how much is to be known, and by what means it may be attained. His labours will also be useful to those of our own countrymen, who are already engaged in inquiries concerning the Interior Parts of Africa. Memoir on the Necessity and Means of arming Buildings with Conductors, to preserve them from Lightning. By J. B. LEROY. On the subject of conductors much has been written: some authors prefer the knobb'd; others, those which are pointed. The prevalent practice in England is in favour of the latter kind but still the subject is clouded with many doubts; and in fact it must necessarily be so, since the theory of lightnings &e, is by no means clearly and satisfactorily established. When a Leyden phial is charged, the inside is said to be in a positive state, the outside in a negative; the former has a superabund, ance of electric fluid, the latter a deficiency. Analagous to this case, it is contended, is that of the air, earth, &c. in a thunder storm; an electric cloud answers to the inside coating of the Leyden phial, the earth to the outside; the cloud is in a positive state, the earth in a negative, or contrariwise; and when a discharge takes place, the equilibrium between the cloud and the earth is restored. Without adducing arguments and facts, however, and many may be brought against this theory, a much more obvious and reasonable analogy offers itself, in making two different clouds answer to the two surfaces of the electrical jar, and the earth to operate simply as a conductor between these two clouds, when in the relative states of superabundance and deficiency. The excellence of the construction of a conductor must then depend on the truth of one or another of these theories. If the latter theory be true, if The work of Mr. Park, however, which has been just published, but which we have not yet had time to read, will probably afford much curious and important information on this subject. the the earth acts merely as a conductor, then a pointed conductor erected at the gable end of a house, or elsewhere, can be of small use; or, it may even be the cause of destruction to the building which it was meant to protect: for the conductor, elevating itself towards a charged cloud, by rendering the communication between the two clouds sufficiently complete, may invite the stroke which would otherwise not have taken place, or perhaps have gone by a different route. The author of the present memoir gives directions for the construction of his paratonnèrres, or pointed conductors: but their construction does not differ essentially from that of conductors usually erected in England. According to his own confession, buildings have been struck by lightning even when armed by these conductors; a fact in our minds by no means remarkable, but a strong argument against the utility which they are intended to promote, and the truth of the system on which they are constructed. Application of the Circle to observe the Meridian Altitudes of Stars. By JEAN DOMINIQUE CASSINI. In this short memoir, we find mention of the observations which were first made by means of the entire circle, introduced as an astronomical instrument, by Borda; and which was remarkable for its precision and exactness. M. de la Lande has described this instrument in his Connoissance des Temps for 1798. Observations of Stars, made at the Military School, with a Mural Quadrant of seven Feet and Half; in 1784 and 1785. By JOSEPH LEPAUTE D'AGELET. An account of the labours of this young astronomer is published in the Journal des Savans for 1791; and also, with additions, in the Connoissance for 1798. He left France in 1785 with M. de la Pérouse, and shared the fate of that celebrated and lamented navigator. Some papers on Chemistry, and on other subjects, remain to be noticed but these we must defer to another opportunity. [To be continued.] ART. X. Abrégé des Mémoires, &c.; i. e. An Abridgment of the T HIS abridgment is far less exceptionable than the original work, and forms a very convenient compendium of its facts and principles. It is divided into six parts. The first part analyzes the anti-christian conspiracy of the French philosophers; a conspiracy, as we have already obAPP. REV. VOL. XXVIII. Pp served, Wood....e. served, completely established; and which, as we conceive, is likely yet to succeed in all catholic countries, where the public religion has certainly not those characters which adapt it for credibility in an age of information. We should expect that it will be least successful in Denmark, where the magistrate has withdrawn the national act of uniformity; and where the public religion has nearly found that level, to which Christianity tends in the present state of literary inquiry. The second part examines the supposed conspiracy of the sophists of rebellion against kings. When a rebellion is already undertaken under a royal form of government, it very naturally adopts a speculative hostility to monarchy, as a mean of strength. Traces, therefore, of this à posteriori enmity are to be found in the recent writers of the French :-but of a previously concerted plan for the abolition of monarchy, we still look in vain for the symptoms. The writings of Rousseau alone, and he was kept aloof by the other philosophers of France from their combination-rooms, tended decisively that way. The private correspondence of D'Alembert offers evidence indeed of his individual republicanism: but, as he did not publish these opinions, they do not evince the system of the party. Beaumelle is not named by the Abbé. The death-bed penitence of the anti-christian philosophers, which rests, we believe, on very satisfactory evidence, should have been narrated in the first chapter; for they are not stated to have repented of republicanism, but of atheism. Part III. enters on the general spirit and tendency of the powerful and diffusive sect of free-masons. We have already given our reasons for believing (vol. xxv. p. 307) that the opi nions of the free-masons were rather a consequence than a cause of the national spirit of France; and were neither essentially nor systematically directed to revolutionary ends. In addition to the arguments already adduced, be it observed that, out of two hundred songs of the free-masons, collected in Van Laak's Lire Maçonne, and accompanied for the use of the fraternity with the usual tunes, not above four contain any sentiments which could be perverted by the sophists of tyranny into invitations to sedition. If any of the poets invoke the muse Eleutheria, it is Monsieur de Vignoles. The story of the mimic assassination, copied from Montjoye's Romance, is here repeated (p. 161) with unabated confidence. The derivation of the Masons from the Templars, and not from the Rosicrucians, is also still maintained; although the introduction of a degree of Knights Templars appears to be long posterior to the institution of the Masonic order. They are also derived (p. 187) from the Albigenses; as if it were necessary to fling every schism into the cauldron whence this quintessential heresy is to be distilled. Ramsay's Masonry Dissected, 1731, gives the first hint of occult lodges; which had probably in view the restoration of the Stuarts. The fourth part relates to Illuminism, of which we have spoken enough, vol. xxvii. p. 512. Secret societies are not likely to flourish much under any government which tolerates and courts publicity. The celebrated Herder probably alludes to this association in the second volume of his Letters on Humanization, (p. 143,) where he so beautifully sketches the idea of a perfect sect. The fifth part continues the same subject. The map of the provincial distribution of the lodges recalls to mind the interior government of the English Anabaptists. Part VI. contains the ridiculously unsuccessful attempt of the Abbé, to attribute the enormities of the Parisian proscribers to the Illuminés of Germany. Extracts cannot be necessary from a book which is itself all extract from volumes already noticed in detail. The work has gained in neatness of arrangement; and it retains those brilliant and eloquent passages which so agreeably relieve the reader. ART. XI. Annales de Chimie; i. e. Chemical Annals, by Citizens CCORDING to the promise in our last Appendix, we now Account of an Instrument proper for measuring the Bulk of Bodies, without plunging them into any Liquid. By M. H. SAY. This paper requires the accompanying plate, in order to be properly understood. Analysis of the Earth from the Pulo of Molfette in Apulia. By M. PELLETIER. This earth contains above 40 parts of nitrat of potash in one hundred. Some notes by the Abbé FORTIS, on this natural nitre bed, shew how miserably so rare a treasure was managed under the old Neapolitan government. Tay. Extract from two Memoirs on Cork. By B. DE LA GRANGE. It appears from this paper that the acid of cork differs, in the proportion of its principles, and in its properties, from all other vegetable acids. It is not crystallizable, which distinguishes it from the citric acid: its precipitates of iron are yellow:-it is entirely volatilized by heat; and it is obtainable in a concrete form; which last circumstance distinguishes it from the malic acid. It takes away metallic substances from the nitrous acid; as also iron, copper, and zinc, from the sulphuric; and it forms salts, all more or less deliquescent. Extract from a Memoir, by M. PROUST, on Prussian Blue. M. PROUST informs us that there are two sulphats of iron, one green, crystallizable, containing of oxygen, insoluble in spirit of wine, unalterable by gallic acid, and yielding not a blue but a white precipitate to alkaline prussiates :-the other, red, deliquescent, not crystallizable, soluble in alcohol, and containing of oxygen. This sulphat has exclusively the property of giving a blue colour with alkaline prussiats. Prussian blue, kept in a phial with water impregnated with sulphurated hydrogen, loses the portion of oxygen, which makes the difference between the white and the blue sulphat; and the prussiat, thus reduced to whiteness, has exactly the same properties with regard to alkalies, as the white prussiat made immediately from the green sulphat.. Letter of M. BARTHOLDI 0; a Calculus from the Rectum of a Horse. The experiments here related give for the constituent parts of this calculus, Extract from a Memoir on Camphor. By B. DE LA GRANGE. The author concludes that camphor is an oil rendered concrete by carbon; for, by addition of alumine and distillation, there may be obtained a volatile oil and carbon. By nitre and acid may be obtained an acid different from all vegetable acids in its crystallization; in its solubility in the cold; in its burning without residuum; in its not precipitating lime-water; in its producing no change on indigo, dissolved in sulphuric acid; and in forming peculiar salts, which give to the blowpipe a blue flame. A second paper occurs below. On the spontaneous Action of concentrated Sulphuric Acid on Animal and Vegetable Substances. By M. M. FOURCROY and Vau QUELIN. We |