Mr. Davy means to apply himself to the solution of these important questions; ut as the enquiry now stands, he thinks it evident that he is correct with respect to the composition and decomposition of ammonia; and that MM. Gay Lussac's and Thenard's idea of the decomposition of the potassium, and their theory of its being compounded of hydrogen and potash, are unfounded: for a considerable part of the potassium is recovered unaltered; and in the entire de composition of the fusible substance, there is only a small excess of hydrogen above that existing in the ammonia acted upon. The phenomena of the process prove the, same thing. After the first slight effervescence, owing to the water ab. sorbed by the potash, formed upon the potassium during its exposure to the air, the operation proceeds with the greatest tranquillity. No elastic fluid is given off from the potassium. The crystallized substance formed in the first part of the process, may be considered as a combination of asimonium and potassium; for it emits a smell of ammonia when exposed to air; and is lighter than potas. Sium. Mr. D. first thought, that a solid compound of hydrogen and potassium might be generated in the first part of the operation; but his experiments do not favour the opinion. Potassium is very soluble in hydrogen; but, under common circumstances, hydrogen does not secm absorbable by potassium. In the examination of sulphur, Mr. Davy made use of that which had been recently sublimed, and the power applied to it was that of a battery of 500 double plates of six inches highly charged. The action was most intense, the beat strong, and the light extremely brilliant: the sulphur soon entered into ebullition, clastic matter was formed in great quantities, and the sulphur, from being of a pure yellow, became of a deep red brown tint. The gas proved to be sulphuretted hydrogen. In other experiments, upon the union of sulphur and potassium, it was proved, that these bodies act upon each other with great energy; and that sulphuretted hydroden is evolved in the process, with intense light and heat. In heating potassium in contact with compound inflammable substances, as rosin, wax, camphor, and the fixed oils, it was found that a violent inflammation was occasioned; that hydrocarbonate was evolved; and that when the compound was not in great excess, a substance was formed, spontaneously inflammable at common temperatures, the combustible materials of which were charcoal and potassium. Here was a strong analogy between the action of these bodies and sulphur on potassium. Their physical properties likewise resemble those of sulphur; for they agree in being non-conductors, whether fluid or solid; in being transparent when flaid, and semi transparent when solid, and highly refractive. Their affections by electricity are likewise similar to those of sulphur; for the oily bodies give out hydrocarbonate by the agency of the voltaic spark, and become brown, as if from the deposition of But the resinous carbonaceous matter. and oily substances are compounds of a small quantity of hydrogen and oxygen with a large quantity of a carbonaceous basis. The existence of hydrogen in sulphur, is fully proved; and the substance which can be produced from it in such quantities, cannot be considered as an accidental ingredient. A The reddening of the litmus paper by sulphur that has been acted on by voltale electricity, might be ascribed to its containing some of the sulphuretted hydrogen formed in the process; but even the production of this gas is an evidence of the existence of oxygen in sulphur. Mr. D. heated four grams of potassium, in a retort of the capacity of twenty cubical inches; it had been filled with sulphuretted hydrogen, dried by means of muriate of lime: as soon as the potas sium fused, white fumes were copiously emitted, and the potassium took fire, and burnt with a most brilliant flame, small quantity of the residual gas only was absorbed. The non-absorbable gas was hydrogen, holding a minute quantity of sulphur in solution. A yellow subis mate lined the upper part of the retort, which proved to be sulphur. The sold matter formed was red at the surface, like sulphuret of potash; but in the interior it was dark grey, like sulpharet of potassium. The piece of the retort containing it, was introduced into a jar inverted over mercury, and acted upon by a small quantity of dense muriatic acid, diluted with an equal weight of when there were disengag water; ed two cubical inches and a quarter of gas, which was sulphuretted hydrogen. This, and other experiments, concur in proving the existence of a principle in sulphuretted sulphuretted hydrogen, capable of de stroying partially the inflammability of potassium, and of producing upon it all the effects of oxygen. Sulphuretted hydrogen may be formed, by heating sul phur strongly in hydrogen gas. Now if we suppose sulphuretted hydrogen to be formed by sulphur dissolved in its unal tered state in hydrogen, and allow the existence of oxygen in this gas, its exist ence must likewise be allowed in sulphur; for we have no right to assume that Sulphur in sulphuretted hydrogen, is combined with more oxygen than in its common form: it is well known, that when electrical sparks are passed through sulphuretted hydrogen, a considerable portion of sulphur is separated, without any alteration in the volume of gas. Hence the intense ignition produced by the action of sulphur on potassium and sodium, must not be ascribed merely to the affinity of the metals of the alkalies for its basis, but may be attributed like wise to the agency of the oxygen that it contains. The minute examination of the circumstances of the action of potassium and sulphur, confirms these opinions. When two grains of potassium, and one of sulphur, were gently heated in a green-glass tube filled with hydrogen, there was a most intense ignition produced by the action of the two bodies, and one-eighth of a cubical inch of gas was disengaged, which was sul phuretted bydrogen. Now sulphuret of potash produces sulphuretted hydrogen, by the action of an acid; and if the sulphur had not contamed oxygen, the hy drogen evolved by the action of the potassium ought to have equalled at least two cubical inches, and the whole quantity of sulphuretted hydrogen ought to have more: and that so much less sulphuretted hydrogen was evolved, can only be ascribed to the larger quantity of D oxygen furnished to the potassium by the larger quantity of the sulphur. "From the general tenour of these various facts," says Mr. D., " it will not, I trust, be unreasonable to assume, that sulphur, in its common state, is a com pound of small quantities of oxygen and hydrogen, with a large quantity of a basis that produces the acids of sulphur, in combustion; and which, on account of its strong attractions for other bodies, it will probably be very difficult to obtain in its pure form." In metallic combinations, it probably retains its oxygen and part of its hydrogen. Metallic sulphurets can only be partially decomposed by heat; and the small quantity of sulphur evolved from them in this case, exists in its common state, and acts upon potassium, and is affected by electricity in the same maaner as native sulphur. Mr. William Sewel, of the Veterinary College, discovered, some years since, a canal in the medulla spinalis of the horse, bullock, sheep, hog, and dog. Upoa tracing the sixth ventricle of the brain, which corresponds to the fourth in the human subject, to its apparent termination, he perceived the appearance of a canal, continuing by a direct course into the centre of the spinal marrow. Upon close examination, he finds its diameter large enough to admit a large-sized pin; from which, by incision, a sinall quantity of colourless fluid issues, like that contained in the ventricles of the brain. The canal is lined by a membrane, resembling the tunica arachnoidea, and is situated above the fissure of the me dulla: it extends as a continued tube through the whole length of the spinal marrow; and a free communication of the limpid fluid which the canal contains, is kept up between the brain and whole extent of spinal marrow, VARIETIES, LITERARY AND PHILOSOPHICAL. R. JONATHAN SCOTT is preparing a new edition of his Persian Tales, entitied, the Behar Danésh, or Garden of Knowledge; and we are assured that sir Gore Ouseley, sir William Ouseley, and other orientalists who have collated the translation with the original, have spoken in the highest terms of the utility of Dr. Scott's literal version to those who study the eastern style of composition, and particularly to those who wish to acquire a knowledge of the manners and customs of Hindoostan. Mr. GEORGE CUMBERLAND, of Bristol, author of Thoughts on Outline, Hafod, Life of Bonafoni, &c. has in the press, press, and will publish next month, two volumes of Original Tales. He is like wise preparing for publication a work with sixty plates, on the Principles of the Composition of the Ancients. The amateurs of the fine arts will be pleased to learn that it is intended to publish by subscription, a facsimile of Wilson's Sketch Book, being Studies and Designs by that great artist, made in Italy and Rome, in the year 1752. It will consist of fifty Plates, the size of the Originals, to be engraved by Mr. J. WHESSELL, and will form a demy quarto volume. Mr. DALLAS is preparing for the press a new edition of the novels of Percival Aubrey, and the Morlands, to be printed in a uniform manner; making together six volumes instead of twelve. To these he proposes to add a seventh volume, containing poems, dramas, and moral essays. The Royal Free School, Borough Road, Southwark, which is the establishment of Mr. JOSEPH LANCASTER, has in it above one thousand scholars, the expense of whose education last year did not cost four shillings per annum each child. The seminary for training schoolmistresses, is under the care of his sister, Miss MARY LANCASTER The governess of the school, in conjunction with her sister, has reduced to practice a recent discovery in the art of teaching needlework, which will soon be published, but at present is not understood by any per son except the above, who are anxious to establish its self-evident perfection on the most clear basis, before the details are submitted to the public. By means of this, any girl may teach others to work with the same facility, as they may be taught to read after Mr. L.'s original method. Any school of girls, however large, may be supplied with materials at the most trilling expense; and one mistress may superintend the needlework with as much case to herself, as one master on the British system can teach eight hundred or a thousand boys reading, writing, and arithmetic. This plan is just at present kept from public view, but in a few weeks is intended to be published. A new volume of essays, by the London Architectural Society, will be ready for the public in a few days. An historical and scientific disquisition on the Doric Order of Architecture, by Mr. E. AIKIN, in folio, with seven plates, S in which the examples from antiquity are drawn to one scale, will also appear at the same time, under the auspices of the Same society. Miss LUCY AIKIN has in the press, Epistles on the Character and Conditon of Women, in various Ages and Nations, with other poems. Mr. WALTER SCOTT has in the press a poem, in six cantos, entitled, the Lady of the Lake. His Royal Highness the Prince of Wales has addressed a letter to Lord Grenville, chancellor of the university of Oxford, requesting him to present to the university, in the name of his royal high ness, four of the papyri, or rolls from Portici, together with fac-simile copies, plates, and engravings, from other rolls. A life of the late Mr. HOLCROFT is just gone to the press. The earlier part was dictated by himself during his last illness; and it was his intention, had his life been prolonged, to have completed his own biography. The portion which he was unable to finish has been drawn up by a gentleman with whom he was for a considerable time in habits of intimacy. Translations of the Medea and Octavia of Seneca, with other poems, onginally translated by a member of Trinity college, Cambridge, may soon be expected to appear. A collegiate seminary is establishing by subscription at Llanddewlbrefi, under the patronage of the learned and benevolent bishop of St. David's. It is intended to be on a large scale, for the admission of youths designed for the church; who will have all the advantages of an university education, free of expense. The medical student and practitioner will soon receive from the pen of Dr. G. H. TOLMIN, of Wolverhampton, a work under the title of, Elements of the Practice of Medicine, in which that important subject will, for the first time, assume all the interest of a practical science. Miss MARY HOUGHTON has a work in the press, in three volumes, entitled, Mysteries of the Forest, which bids fair to rival the best productions of the admired RADCLIFFE. The Rev. F. A. Cox proposes t› publish by subscription, the Dissertations, Historical, Critical, Theological, and Moral, on the most memorable events of the Old and New Testaments, of Saurin, Roques, and Beausobre. Mr. Mr. DYмOCK, of the grammar-school of Glasgow, has in the press a new edition of Decerpta ex P. Ovidii Nasonis Metamorphoseon Labris," with notes at the foot of the page, and a copious index of the proper names at the end of the volume, for the use of schools. Mr. GEORGE SINGER'S lectures on Electro-Chemical Science, commence on Thursday the 10th of May, at the Scientinc fustitution, No. 3, Prince's-street, Cavendish-square, and will continue on Monday and Thursday evenings, at eight o'clock. Mr. GEORGE CHALMERS has in the press, a new edition of his Estimate of the Comparative Strength of Great Britain, and of the Losses of her Trade, from every war since the Revolution; corrected and continued to 1810. The same gentleman is superintending a new edition of Natural and Political Observations and Conclusions upon the State and Condition of England, 1696, by Gregory King, esq. Lancaster-Herald, to which he has annexed a life of the author. Mr. CHALMERS is also preparing for publication, a Chronological Account of the Commerce of England from the Resturation to 1810, distinguishing the years of war; on a board to hang up, or au a case for the pocket. Early in May will be published, in one voluine, octavo, the State of the Established Church, in Ten Letters to the Right Honourable Spencer Perceval, with an appendix of official documents relative thereto. Mr. DONOVAN has been for some time engaged in preparing a comprehensive work on the Natural History of the British Isles, on a popular as well as scientific plan. Mr. B. H. SMART, teacher of elocution, will speedily publish a Grammar of English Pronunciation, compiled on a new plan, but on plain and recognized principles, which will supply a practical method for the removal of a foreign or provincial accent, vulgarisms, impediments, and other defects, of speech, and furnish pupils of all ages, particularly those destined for public situations, with the means of acquiring that graceful articulation upon which alone a superior delivery can be founded. Constance de Castile, a poem, from the pen of Mr. SOTHEBY, may shortly be expected to appear. MONTHLY Mag. No. 198. Mr. EDWARD DRIVER is preparing a complete map on six large sheets, of the manor of Lambeth, froin actual admeasurement, made by order of the commissioners, under an act of inclosure passed in 1806, comprising a district seven miles in length, from Westminster-bridge to Norwood Common. It will contain a complete delineation of every person's estate within the manor, distinguishing the freenold from the copyhold, also every house, yard, bunding, and inclo sure, of each person's property, and their exact quantity, together with all the allotments, and also the several parcels of land which have been sold under the act. A General History and Survey of London and Westminster, founded principally on Strype's edition of Stow, with introductions, notes, and supplements, bringing the whole down to the present time, is in the press, in a royal quarto volume, illustrated by numerous engravings. The Rev. RALPH CHURTON is superintending the publication of the works of the Rev. Dr. TowNSON, late archdea con of Richmond, to which will be prefixed an account of the author, an introduction to the discourses on the gospels, and a sermon on the quotations in the Old Testament. They will form two octavo volumes. A work will shortly appear in one volume quarto, under the title of Extracts from the Diary of a Lover of Literature. It will comprise a series of critical observations on eminent works, literary anecdotes and conversations, remarks on distinguished characters, discussions of various metaphysical, political, and religious topics, and notes on different excursions through picturesque parts of this Island. In order to confute the idea that the silk-weavers of this country cannot produce manufactures equal to the French, a society was formed some time ago, called the Flag Association, with a view to the production of such a specimen of double brocade weaving as had never before been attempted. In conse quence, there is now in the room a flag two yards wide, the ground a rich crim son satin on both sides, and brocaded on each side alike with appropriate colours tastefully and elegantly shaded by the artist. Upon its surface will appear within an oval, a female figure, embleЗА matic matic of the art of weaving, reclining with pensive aspect on a remnant of brocade, lamenting the neglected state of this manufacture. Enterprise is represented raising her up and cheering her drooping spirits, by shewing her a cornucopiæ, pouring forth its treasure, a symbol of the resources of Britain, and indicating that the wealth and liberality of this nation are ever ready to support Jaudable undertakings. Close to Enterprise, and beneath a representation of the all-secing eye of Divine Providence, Genius appears erect, pointing to a flag displaying the weavers' arms, placed upon the temple of Fame. The corners of the flag will be adorned with emblems of peace, industry, and commerce; and an edging with a curions Egyptian border, will exhibit a combination of figures and devices, indicative of the design for which it was formed. The separately dropped into water. A medicinal spring has lately been Cab. Inch, 16.30 4.50 Mr. LUKE HOWARD, of Plaistow, has detected a criminal imposition, the knowledge of which cannot be too widely circulated, or its effects too carefully guarded against. A very large quantity of glass of lead, has, by some means, found its way into the London market, as glass of antimony. This imposition is sure to be discovered in the operation to which the latter is chiefly applied, the making of emetic tartar; but it is highly necessary for the consumers of smaller quantities, as in the vitrum ceratum, and vinum antimonii, to be acquainted with the following distinctive characters of the two; that those who have bought the The solid contents in 100 parts are: article within the last twelve or eighteen months, may assure themselves of its being genuine. The public health, and even the lives of many patients, may be considered at stake on this occasion. Glass of antimony has a rich brown or reddish colour, with the usual transparency of coloured glasses. The glass of lead is of a deeper and duller colour against the light, is much less transparent, and even in some samples quite opaque. The specific gravity of the true, never exceeds 495; that of the spurious, is 695: or in round numbers their comparative weights are as 5 to 7. Let twenty grains be rubbed fine in a glass mortar, adding half an ounce of good muriatic acid. The true dissolves with an hepatic smell; the solution is turbid, but has no sedinient. The spurious turns the acid yellow, giving out an oxymuriatic odour, and leaves much sedunent, Let a little of each solution be Carbonate of iron 21. Graini 5.25 6:00 473 3.25 2:00 21.25 Mr. G. CUMBERLAND, having found the wear of steel files rather expensive, has been induced to seek a substitute for abrading hard bodies, and has discovered that clay may be employed for this purpose. Wet pieces of this substance, folded up in maslin, cambric, or Iristi linen, forced by the pressure of the hand into the interstices of the threads so as to receive a correct mould, and then well baked, form a new species of file, capable even of destroying steel, and very useful in cutting glass, polishing and rasping wood, ivory, and all sorts of metals. A pound |