DISCOVERIES AND IMPROVEMENTS.

TO PROCURE FINELY DIVIDED PLATINUM.

The following process will granulate, or rather produce, platinum in a state of Jurity: :

Dissolve the crude platinum in nitromuriatic acid, and add a solution of muriate of ammonia, which will precipitate ahe platinum, which precipitate heated ,white hot in a clean crucible, will leave the platinum perfectly pure. J. L.

AN EASY METHOD OF DARKEN ING MAHOGANY.

Nothing more is necessary than to wash the mahogany with lime-water, which may readily be made by dropping a nodule of lime into a bason of water. J. L.

EXTRAORDINARY DISCOVERY IN

HYDRAULICS.

A prospectus has been circulated in Paris, of a new machine, which, if we may believe its inventors, will effect wonders in hydraulics. They engage to supply a small steam-engine, which will raise water to the height of 60 feet, at the rate of fifteen quarts per minute. The machine will, it is said, consume but a pennyworth of coals in an honr, in which time it will raise 900 quarts to the specified height. It is to cost 600 francs, and to last more than a hundred years. The proprietors likewise offer, at a progressive advance, machines which will raise double, treble, and decuple heights (i. e. 120, 180, or 600 feet), and thus in infinite progression. The proprietors are Messrs. Croissons, brothers, both of

them pupils in the Polytechnic School, and one of them is a commandant of artillery, whose talents are said, in the Parisian circles, to inspire the greatest confidence. They keep their discovery a secret, and will not divulge it till they have raised subscriptions for 20,000 inches of water, according to their mode of calculation.

TO CORRESPONDENTS.

We shall begin the new year with giving a place to our friend" the Plumber at Bristol's" proposition.

To Z. a further description?—Yes. "We have to apologize to S. R. for the miscarriage of a letter intended for him. He will oblige us by sending again to our publishers.

Keating's "Farewell," though it does credit to his warmth of affection, is not correct enough for our pages; and as we have no poet on our establishment to give it the refining requisite, it must necessarily stand over.

The letter of A. R. K. requires that we should make some inquiries before we can adopt the plan suggested, of which, on a first perusal, we think highly.

THE intention of the present scheme is to introduce a more economical and expeditious mode of conveyance than is now in use, for vehicles of every kind, whether employed in the transport of persons or merchandize⚫ It is proposed to supersede entirely

the necessity of horse power in all public waggons, stage and mail coaches, post chaises, &c. and to employ in its stead the more potent agency of steam. A careful examination of the drawings now presented to the public, as a plan of a general iron rail-way, will, it is hoped, clearly demonstrate the ease, safety, and celerity, with which vehicles of every denomination, for the conveyance of goods and persons, may be propelled by mechanic power. The six parallel rail-ways which extend the whole length of our inner plate, form a general iron rail-way, which might run in a direct line from London to Edinburgh, and from London to Falmouth. The branches from the direct line require that there should be one or two rail-ways for carriages going, and an equal number for those returning.

tracks or rail-ways, in case a carriage of superior speed be obstructed by any other of inferior speed; alsoTM in case of accidents, or of any necessary repairs.

The circular plates are to be let into the general iron rail-way, wher◄ ever the communication with a branchrail-way may require it.

The sliding frame should be laid at regular distances, as the public convenience may demand; also for particular or local accommodation, as experience shall best instruct.

The rollers, or machinery, on which the circulars, plates, and sliding frames are to act, must be of sufficient strength and power to carry any weight whatever. The operation of these machines may be effected by horse or steam power, as circumstances may determine.

The rack or cog-rail, in each railway, is where the cog-wheel of the steam-engine employs its force to impel the caravans, waggons, and coaches. Being placed in the middle of the track, it gives the most uniform power to the permanent action of the steam-engine, and would also exclude the use of horses, and thereby preserve the rail roads from destruction and continual dilapidation, the attendant consequences of employing horses.

Steam-carriages, on the plan now proposed, would answer every purpose required by the intercourse of the country, and clearly prove, that. the vast expenses now caused by the employment of horses is totally unnecessary. It will scarcely be credited, that a stock of 100,000 horses renewed every four years, will cost for their keep and interest of capital in the course of twelve years, no less than thirty-four millions seven hundred thousand pounds. The great saving which might be effected by the employment of steam-power, will be obvious to every one when it is mentioned, that instead of each coach changing horses between London and Edinburgh, say 25 times, requiring 100 horses, besides the supernumerary ones kept at every stage in case of accidents, the whole

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with greater personal accommodation to the passengers, by the simple expense of one steam-engine.

As a permanently improving Bource of revenue to government, this plan would have no parallel. The diurnal returns, at the most moderate rate, or tax upon each vehicle, would annually produce many millions: indeed no limits can be assigned to the increase of wealth which this change in our inland conveya..ce might produce. There is no branch of agriculture, no branch of commerce, or of arts, but would partake of its endless prosperity.

T. G.

(For the Mechanic's Magazine.) BORING FOR WATER AROUND THE METROPOLIS. Previous to the Tottenham fountains being produced by boring, I was acquainted with the fact of water rising to within a few feet of the top (varying only according to the irregularity of the ground) of

wells sunk through an impervious clay of about 300 feet in depth, in the neighbourhood of Clapham common, at a height considerably above the Thames; and in consequence of the effect being the same on the north side of the river as there, which is proved by the Tottenham fountains, I have, with a view of showing that a more valuable advantage may be taken of this circumstance, been at some little trouble to investigate how far it can be made available, and the result I will briefly state.

London and its environs, to the extent of some miles, are situated on an immense bed of clay, of from 2 to 300 feet in depth, forming a valley generally of considerable extent, but of no great breadth, not very distinctly defined, and consequently not very perceptible. Through this valley flows the Thames, without having any connection with the main springs. The rain-water accumu

lated in the porous soils in the immediate vicinity of this body of clay, cannot fall to a level with the Thames, until it has risen to a sufficient height to run over the surface of the clay, oozing through the gravel by which that is covered, either into the Thames, or the nearest tributary stream. Hence the cause of the water rising above the Thames, as at the fountains at Tottenham, &c. The height from which the water there issues, is about twenty feet above high water mark, and by adding thereto the height due to the velocity of the issuing fluid, it agrees, as nearly as possible, with the height at Clapham.

It may be bence deduced that the whole of the houses on the southward side of the river may be supplied with water by boring. The water can be laid on to as many houses as the supply from each boring is equal to, at, at least, one-half the charge per annum of the present water-work companies, and the public will besides be provided with the most pure and soft water that can be obtained. The wells would be seldom, if ever, out of repair, and require no expense when completed, not even a turncock. Were this mode of supplying water undertaken on any considerable scale, it would afford to capitalists one of the best means of investing property ever undertaken, and pay at least 25 per cent.

Having such a considerable fall in the Borough, these fountains may be employed with advantage and success as a moving power to machinery, where no great force is required. In other situations they might be introduced both for purposes of ornament and utility. In St. James's Park, for example, a fountain might be opened, which, after playing, would afford a continued supply to that stagnant pool the canal, by which it would be considerably improved.

P. S.--Your correspondent G. S. can scarcely be serious in his inquiry for information respecting the effect of boring for water in porous strata, as I should consider the subject too well understood to admit of two opinions. It is certainly true, however, that most of the publications (at least of those I have road), respecting the effect of boring in the neighbourhood of London, would lead one to conclude, that its application and effect would be universal, as no explication whatever, of the cause of this effect is entered into. In all porous soils, where the surface of earth is below the level of the spring, the water will always find means of escaping without the aid of human intervention; hence the cause of our rivers, which carry off all superfluous waters; but if we open the earth by boring, or otherwise, above the level of the spring, the only means of coming at this useful element is, by lifting it to the surface, unless your correspondent's townsmen are possessed of the knowledge of some secret reservoir acted upon by steam, produced from some caldrons in Etna, to do the labour for them, to which we must consider their sapient endeavours are directed. Yours, respectfully,

G.

From another Correspondent on the same subject.

Mitcham, Surrey. SIR;-On looking over No. 16 of your Magazine, I observed a question asked under the head of "Boring for Water," namely, Whether, there is any her spring or reservoir of water in the bowels of the earth, exclusive of what may be termed temporal or perennial? As it respects springs of water, I am not aware what may be termed temporal or perennial, knowing but few that. give a constant yearly supply. As a real deprivation of water in wells of that description ▸ too often occurs, I beg to observe, that in my practice of boring for water, I have frequently found another, or mainspring of water, that: