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SCIENTIFIC AND MISCELLANEOUS INTELLIGENCE.

Decomposition of the Metallic Sulphates by Hydrogen.-The composition of several doubtful sulphurets has been ascertained by Arfvredson, by reducing their corresponding sulphates by hydrogen. A summary of his results is subjoined.

The artificial sulphuret of manganese, sometimes considered a sulphuretted oxide, is accurately speaking, a compound of 1 proportional of sulphuret of manganese, with 1 proportional of protoxide, called by Arfvredson an oxysulphuret.

The reduction of sulphate of cobalt also gave an oxysulphuret. The reduction of sulphate of nickel yielded a subsulphuret. A current of sulphuretted hydrogen, passed over red-hot oxide of nickel, gave a simple sulphuret, which proved to be the composition of native sulphuret of nickel, or pair pyrites.

The reduction of protosulphate of iron gave a subbisulphuret, containing less sulphur than magnetic pyrites, which Arfvredson, on the authority of Stromeyer, states to be a compound of 1 proportional of bisulphuret of iron with 6 proportionals of simple sulphuret. The reduction of the subpersulphate gave a sulphuret, containing 8 proportionals of iron to 1 of sulphur, or a suboctosulphuret.

The reduction of sulphate of lead, yielded a compound of metallic lead and sulphuret of lead.

The foregoing summary is abstracted from the paper of Arfvredson, in the May number of the Annals of Philosophy. The results in proportionals, and the nomenclature, in reference to equivalent numbers are given in accordance with the numbers adopted by the English and American chemists. Arfvredson follows Berzelius in these particulars; and it is well known, that the latter chemist, from an artificial mode of viewing the subject, makes the equivalent numbers for many substances, especially the metals, double those adopted by other chemists. This want of conformity in the numbers pitched upon, however, does not imply any disagreements as to the actual proportions of combination. The chemical compounds, in the paper referred to, are expressed by the method of chemical notation invented by Berzelius; but the formulæ are, in so many instances, incorrectly printed, as to make it difficult to follow the author without considerable labour.

Influence of the density of the air on the rates of chronometers. Mr. Harvey has lately discovered, that the going of chronometers is influenced by the density of the air; their rate being in most cases accelerated when the density is diminished, and retarded, when the density is increased. In a few cases, however, the reverse is the fact. These observations are important, as they point out a cause for the irregular going of clocks, not heretofore attended to.

Discovery of Glucina in the chrysoberyl.-Mr, Henry Seybert has lately communicated to the American Phil. Society, an important paper giving analyses of the chrysoberyls both of Haddam in Connecticut, and Brazil. The paper is in course of publication in a new volume of the society's transactions, which is soon to appear. In the mean time, it is given to the public, by permission of the society, through Silliman's Journal.

The analyses reveal the interesting fact, not heretofore suspected, that the chrysoberyl contains Glucina to the amount of about 15 or 16 per cent. Mr. Seybert is entitled to this additional merit for the discovery, that the same mineral was analysed in 1822, without detecting the Glucina though it was sought, by that acute and promising chemist Mr. Arfvredson of Sweden. In the analyses by both chemists, the mineral was repeatedly treated with caustic potassa; the insoluble residue, after each fusion, being again subjected to the action of the same alkali. In each analysis, an insoluble residue, not attacked by the potassa, amounting to about one-sixth of mineral employed, was obtained. This inscluble residue was found by Mr. Seybert to be Glucina associated with about a sixteenth of oxide of titanicum; while, according to Arfvredson," on examination, it proved to be pure silica." [See a translation of Arfvredson's paper on the analysis of some minerals, Annals of Philosophy, May 1824!]

Radicals of Silica, Uthria, Glucina and Zirconia.-Berzelius has lately succeeded in insulating the Radical of Silica or pure flint. Heretofore, incomplete evidences only were obtained of the nature of this Radical, insufficient, however, to lead to the belief, that it was more analogous to carbon and boron than to the metals, a supposition now confirmed by Berzelius. The method of obtaining it, consists in acting on dry silicated fluate of potassa, with potassium-a mixture of various substances is thus obtained, which, when washed with water, yields hydroguret of silicon, and this latter, when heated in a crucible, has the hydrogen burnt off, whereby the silicon is obtained pure.

Silicon, is found by Berzelius to vary in combustibility, according to its state of aggregation, resembling carbon in this respect. As usually obtained it burns, when ignited, either in oxygen gas or atmospheric air; but in its densest state, it may be made incandescent without undergoing this process. It burns also in chlorine and in the vapour of sulphur, forming with the former a transparent colourless liquid, smelling like cyanogen, and with the latter, a gray sulphuret.

By a similar mode of decomposition, as applied to yttria glucina and zirconia, the radicals of these earths were also obtained.

Important Invention. Mr. Brodie, foreman of the Carpenter's department in the Gosport Navy Yard, has invented a machine

which promises greatly to facilitate the repairing of damages done to vessels. It is a Box shaped to the mould of the ship, reaching from the surface of the water to the keel, and sufficiently wide to cover the part to be repaired. It is sunk alongside, and brought close to the ship by ropes, and the water is then pumped out by means of an engine. The workmen then descend and execute their task "with as much security as if they were on terra firma." In launching the Delaware 74, an accident occurred, by which the copper, to the length of 3 or 4 feet, very low down and contiguous to the fore foot, was ripped up. Two summers passed away before the casualty was discovered, but during the third, the worm so far perforated the exposed part as to cause the ship to leak considerably. All the skill in caulking, thrumming, &c. that could be exerted, availed nothing, the leak continuing to increase. Finally it was pronounced impracticable to overcome it in any other way than by heaving the ship down, in which operation an expense of $25,000 or $30,000 must necessarily be incurred. It was in this dilemma that Mr. Brodie had his machine constructed. The workmen descended with their tools and commenced operation. The injured plank has been removed, and at this moment, says a writer in the Norfolk Herald of Monday," they are bolting the new plank, nearly 18 feet under water to her side, in complete security."

Simple as the machine is," says the Herald, "such are the important advantages that must result from it, that it cannot but entitle the inventor to the gratitude of his country."

Weighing Locks.-The Locks for weighing boats in the vicinity of this village, are now completed and ready for operation. Their construction is founded upon the known principle of hydrostatics, that the whole weight of a body, which will float in a fluid, is equal to as much of the fluid as the immersed part of the body takes up when it floats. Two wooden locks are formed of equal dimensions, being 86 feet long, fifteen wide, and four feet deep, one above the other, in such a manner that one side of the upper lock extended down, forms also one side of the lower lock. The upper lock has gates of the usual form in lift-locks, and connecting it with the canal on the same level, and the surface of the lower lock is on a level with the floor of the upper lock. The boats are admitted into the upper lock, and the quantity of water displaced, or rather the increase of its volume is ascertained by measuring it, with a graduated scale in the upper lock, drawing it off and finding the difference of measurement in the lower lock. The weight of a boat is then immediately determined by reference to a table calculated for the scale. Complete accuracy cannot be expected; but it will be sufficient for ordinary purposes. The time occupied in weighing a boat will probably not exceed twenty minutes. Utica, N. Y.

Chesapeake and Ohio Canal.-We understand that the Board of Engineers, appointed by the general government, are industriously employed in the examination of the country between the Potomac and Youghiogeny rivers. Three different parties have been despatched, under their instructions, to survey sections of the route for the contemplated Canal. The Board, from the last accounts, were descending the Youghiogeny, intending to proceed to its mouth, and thence ascend the Monongahela and Cheat Rivers. The cursory observation of the Savage and Youghiogeny has been shown them to be excessively rocky and rough, but still offering no insuperable difficulties. In many places the banks are so precipitous that the canal must be made in what is now the channel of the river, and be supported on the lower side by great walls. If the Youghiogeny cannot be commanded on the summit, it will then remain to ascertain if Deep Creek alone will afford a sufficient supply of water. To effect this, a nice measurement of the stream must be made, which the rain has hitherto prevented, having swelled the Creek to such a degree as to render it impassible for several days, except by swimming the horses. The quantity of water in the ordinary state of the Creek, must, of course, be the basis of all calculations as to its power of supplying the summit level. This will, in all probability, be found to be the only point at which a communication can be effected, inasmuch as the ridge of the Great Back Bone stretches at a great height, nearly uniform, through the country-and the Savage is the only stream that breaks through it; so that its sources are in fact, west of the great ridge of the Alleghany.

THE HISTORY OF MATTHEW WALD.

Matthew Wald is the teller of his own story, the relater of his own " eventful_history," in a letter to his nephew; and he commences, perfectly au commencement, with the "Anglo-Saxon Colonization" of Scotland. As we cannot afford to be quite so diffuse, however, we must take a branch of the family tree, rather farther from the root, and shall, consequently, confine our information to a very few details of our hero himself. After the decease of his father, Matthew Wald was brought up, he tells us, at Blackford, by an aunt, and with a cousin, Katherine, to whom his patrimonial estate had been bequeathed; and, till he got an unclein-law, in the person of a reverend Mr. Mather, his former tutor, was tolerably comfortable. The tyranny of his new lord and master, however, he very speedily found unbearable; and, after much skirmishing on both sides, Matthew was sent to finish his studies at St. Andrew's. Uneasy at not hearing, as he had hoped, from home, at the end of the third session, he surprises his relations by returning to Blackford, where he finds the honourable George

Lascelyne domesticated as a pupil of his uncle, and very far advanced in the good graces of his cousin Kate. This determines him to leave the country: he receives from Mr. Mather, his fortune, about a thousand pounds; departs without taking leave; gets plundered of nearly all his property at Edinburgh; and, after several adventures, which we have not space to detail, at length gets fixed, as a domestic tutor, in the family of sir Claude Barr, at Barrmains, having previously changed his name to Waldie, and his cousin having, in the interim, become Mrs. George Lascelyne. Sir Claude's death once more turns Matthew out of doors, when, by the advice of a Dr. Dalrymple, he goes to study physic at Glasgow, and, during his residence there, gets embroiled in a most singular incident, which we shall detail in his own words:

"I lodged in the house of a poor shoemaker, by name John M'Ewan. He had no family but his wife, who, like himself, was considerably beyond the meridian of life. The couple were very poor, as their house, and every thing about their style of living, showed; but a worthier couple, I should have had no difficulty in saying, were not to be found in the whole city. When I was sitting in my own little cell, busy with my books, late at night, I used to listen with reverence and delight to the psalm which the two old bodies sung, or rather, I should say, croon'd together, before they went to bed. Tune there was almost none; but the low, articulate, quiet chaunt, had something so impressive and solemnizing about it, that I missed not melody. John himself was a hardworking man, and, like most of his trade, had acquired a stooping attitude, and a dark, saffron hue of complexion. His close-cut greasy black hair suited admirably a set of strong, massive, iron features. His brow was seamed with firm, broad-drawn wrinkles, and his large gray eyes seemed to gleam, when he deigned to uplift them, with the cold, haughty independence of virtuous poverty. John was a rigid Cameronian, indeed; and every thing about his manners spoke the world-despising pride of his sect. His wife was a quiet, good body, and seemed to live in perpetual adoration of her stern cobler. I had the strictest confidence in their probity, and would no more have thought of locking my chest ere went out, than if I had been under the roof of an apostle.

I

"One evening I came home, as usual, from my tutorial trudge, and entered the kitchen, where they commonly sat, to warm my hands at the fire, and get my candle lighted. Jean was by herself at the fireside, and I sat down beside her for a minute or two. I heard voices in the inner room, and easily recognized the hoarse grunt which John M'Ewan condescended, on rare occasions, to set forth as the representative of laughter. The old woman told me that the good man had a friend from the country with him,-a farmer, who had come from a distance to sell ewes at the market. Jean, indeed, seemed to take some pride in the acquaintance, enarging upon the great substance and respectability of the strapAUGUST, 1824.- -No. 268

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