IMPORTANT INVENTIONS. Important invention in Hydraulics....There is at present circulated in Paris, the prospectus of a new machine which, if we may believe the authors, will overturn all our present system of hydraulics. They engage to supply a small portable steam engine, which will raise the water to the height of sixty feet, at the rate of fifteen quarts per minute. The machine will consume no more than the value of one pennyworth of coals in an hour, to raise nine hundred quarts of water to this height. It will cost six hundred francs, and will last more than a hundred years. No payment is required till the engine has been tried, and given satisfaction: till it is fixed, and raises the water from the well to the roof of the house, which will thus be secured against fire. They offer, for progressive prices, machines which shall raise double, triple, decuple quantities of water, to double, triple, decuple heights, (i. e. 120, 180, or 600 feet, and this in infinite progression. Newly invented Gun....A gun of an entire novel construction, was exhibited a short time back in the gardens of York-House, before the Duke of York. It weighs less than the common musket, though composed of seven barrels; one is of the common length, and in the same position; around it, at the breech, are the six others, of about three inches in length only. The simple act of cocking places each of the short barrels successively in complete connection with the long one, and that of shutting primes it; so that seven discharges may be effected in 30 seconds. It is perfectly safe and accurate, every part being so guarded, as to prevent the possibility of danger, error, or impediment, with great simplicity.

Mr. Pontifex's Patent Apparatus for raising Water by means of Fire...The very limited reading of many ingenious inventors of the present day, seduces them into a belief that every thing that has the air of originality to them, must be equally new to their fellow mortals; a more extended view of the scientific literature of the last century would speedily correct this mistake, and a very considerable saving of time and expense would be the result. These observations unconsciously present themselves from a perusal of Mr. P.'s specification which contains little more than an imperfect description of that stupendous machine the steam-engine. The first application of fire to the raising of water is unquestionably due to the Marquis of Worcester, though it is probable that he merely employed the repellent force of steam of a high expansive power for that purpose.

Captain Savary, who is the next candidate for the honour of this invention, constructed an engine in its effects precisely similar to the one of which Mr. Pontifex now claims the title of original inventor, and to which, indeed, Captain Savary's engine is in many respects superior The Marquis, as we have already observed, merely employed the repellent force of steam, and to this Savary added the pressure of the atmosphere, by which he filled up the vacuum produced from the condensation of the steam, after it had ceased to operate by its expansive force. The latter part of this invention has been adop ed by Mr. Pontifex, whose engine may be thus described :--

Two copper vessels made to fit air tight are connected by what Mr. P. denominates a suction pipe, the lower end of which is immersed in the well from whence water is to be raised: steam is then admitted through two small branch pipes communicating with the boiler, which is again condensed by the admission of a jet of water. A vacuum being thus formed, the pressure of the atmosphere is sufficient to raise the water about thirty feet, which is the extreme capacity of Mr. Pontifex's engine.

To WOLF BENJAMIN, of Plymouth Dock, Umbrella Manufacturer, for a Composition, varying in Colour, with a peculiar Method of applying, for the purpose of rendering Canvas, Linen, and Cloth, durable, pliable, free from cracking, and Water-proof.

To make a black.... First, the canvas, finen, or cloth, is to be washed with hot or cold water, the former preferable, so as to discharge the stiffening which all new canvas, linen, or cloth contains; when the stiffening is perfectly discharged, hang the canvas, linen, or cloth, up to dry; when perfectly so, it must be constantly rubbed by the hand until it becomes quite supple; it then must be stretched in a hollow frame very tight, and the following ingredients are to be used or laid on with a brush for the first coat, viz. eight quarts of boiled linseed oil, balf an ounce of burnt umber, a quarter of an ounce of sugar of lead, a quarter of an ounce of white vitriol, a quarter of an ounce of white lead. The above ingredients,except the white lead, must be ground fine with a small quantity of the above-mentioned oil on a marble stone and mullar; then mix all the ingredients up with the oil, and add three ounces of lamp-black, which must be put over a slow fire in an iron broad vessel, and kept stirred until the grease disappears; in consequence of the canvas being washed and then rubbed,it will appear rough and nappy: The following method must be taken with the second coat, viz. the same ingredients as before, except the white lead; this coat will set in a few hours, according to the weather; when set, take a dry paint-brush, and work it very hard with the grain of the canvas; this will cause the nap to lie smooth.

Third and last coat, which makes a complete jet-black, which continues its colour--take three gallons of boiled linseed oil, an ounce of burnt umber, half an ounce of sugar of lead, a quarter of an ounce of white vitriol, half an ounce of Prussian blue, and a quarter of an ounce of verdigrease; this must be all ground very fine in a small quantity of the above oil, then add four ounces of lamp-black, put through the same process of fire as the first coat. The above are to be laid on and used at discretion in a similar way to paint. To make lead colour, the same ingredients as before in making the black, with the addition of white lead, in proportion to the colour you wish to have, light or dark.

To make green.---Yellow ochre four ounces, Prussian blue three quarters of an ounce, white lead three ounces, white vitriol half an ounce, sugar of lead quarter of an onnce, good boiled linseed oil sufficient to make it a thin quality, so as to go through the canvas.

Yellow.---Yellow ochre four ounces, burnt umbre a quarter of an ounce, white lead six or seven ounces, white vitriol a quarter of an

ounce, sugar of lead, a quarter of an ounce, boiled linseed oil as in green.

Red.---Red lead four ounces, vermillion two ounces, white vitriol a quarter of an ounce, sugar of lead a quarter of an ounce, boiled linseed oil as before.

Grey.Take white lead, a little Prussian blue sufficient to turn it grey, according to the quality you want, which will turn it to a grey colour; a proportion of sugar of lead and white vitriol, as mentioned in the other colours; boiled linseed oil sufficient to make it of a thin quality.

White.--White lead four pounds, spirits of turpentine a quarter of a pint, white vitriol half an ounce,sugar of lead half an ounce,boiled oil sufficient to make it of a thin quality. The above ingredients, of different colours, are calculated as near as possible; but as one article may be stronger than another, which will soon be discovered in using, in that case the person working the colour may add a little, or diminish, as he may find ne

cessary.

The same preparation for wood or iron, only reducing the oil about three quarts out of eight, and to be applied in the same manner as paint or varnish, with a brush.

PRINCIPLES OF ROAD-MAKING EXPLAINED on MR. M'ADAM's new SYSTEM. 1. Forming the Road.---The line being agreed on, the road must be formed, by breaking the natural surface as little as possible, and with no greater convexity than is absolutely necessary to carry off the water. For the general purposes of country travelling, twenty-eight feet is a sufficient breadth of road, with a declivity of three inches from the centre to each side; sixteen feet in the centre should be fully metalled with solid materials, and six feet on each side may be done with slighter materials; but, near to great towns, there should be thirty or forty in breadth of actual road-way laid with solid materials to the full depth. The water courses on each side of the road should be so constructed, that the road-materials may be three or four inches above the level of the water in the ditch.

2. Preparing the Materials.--When stones can be obtained, they ought always to be preferred. They must be broken in small heaps, and in such a manner that the largest piece in the heap shall not exceed six ounces in weight; they will thus unite by their own angles, and form a solid hard substance. If the stones were all broken to six ounces, they would make a rough road; therefore, that size is assumed only as the maximum, and as the best criterion and check for the breaker; for, if no piece of stone shall exceed six ounces, a great proportion of the heap must necessarily be under that size; and, as this is indispensable to the smoothness of the surface of the road,it should be well attended to. The operation of breaking the stones should be performed in a sitting postre, with a small hammer, of about one pound weight in the head, the face the size of a new shilling, well-steeled, and with a short handle. After the stones are blocked out, the breaking may be executed by old men, and by women aud children; and this should be done at the depôt, and never on the road.

When gravel is used for making the road, it must be sifted or riddled in the quarry till it be quite clean and free of earth, and all the large pieces must be well broken, as directed for stones, and in that prepared state earth is of a quality to adhere to the gravel, the gravel is brought to the road. When the it will be advisable to leave in the pit the small or fine gravel, and to use for the road only the larger parts which can be broken; for, while the breaking more effectually beats off the earth, the advantage is obtamed, angular shade which so much favours its conof having the gravel laid on the road in that solidation.

3. Laying on the Materials.---A depth of ten inches of solid materials, prepared as above, is sufficient for any road. No large be placed below the prepared materials, stones, or wood, or other substance, should whether the bottom be soft or otherwise.

Broken stones should be laid on the road to

the above depth at three different times, with following another, and each scattering the light broad-mouthed shovels, one shovel-tuli stones over the surface for a considerable space. There must not be among the broken stones any mixture of earth, or of any other matter that will imbibe water, or be affected with frost; and nothing is to be laid over the clean stones on pretence of blinding or binding.

on the road in light coats, not exceeding two
Gravel, when made use of, should be laid
inches at a time, with a proper interval be-
twixt each coat, to let the gravel settle.

ful person must attend for some time after a
4. Consolidation of the Materials---A_care-
new road is opened, to rake-in the tracks
made by wheels, until the materials consoli-
date.
they will in a short time unite themselves
If properly prepared and applied,
into a mass or body, like a piece of timber or
surface, which will not be affected by vicis-
a board, and will then form a smooth solid
situdes of weather; nor will the stones be
displaced by the action of the wheels, which
will pass over without a jolt, and, conse
quently, without injury.

the above principles, will require no repairs
5. Repairing the Road.---A road made on
The amendment will then be made by an ad-
till, by use,it gradually wear thin and weak.
dition of materials, prepared and laid on as
at first. The period which a road will last
without repairs, depends on the nature of
the materials of which it is composed, and the
terials, whin-stone is the best and most dura-
use to which it is exposed. Of all road ma-
ble; lime-stone consolidates sooner, but,
from its nature, is not so lasting; gravel is
inferior to both, because its component parts
are round, and want the angular points of
contact by which broken stones unite.

weather is not very dry. Before laying on
All repairs should be executed when the
the additional materials, the surface of the
old road must be loosened a little with a pick-
axe, so as to allow the new materials to unite
with the old.

been originally made on a wrong principle,
6. Lifting a Road.---Where a road has
the defect may in general be cured, by lift-
ing and re-laying it.
consist in the undue preparation of the
If the main object.
stones, the mode of cure is this: Turn up the
whole road four inches deep with a strong

pick-axe, short from the handle to the point; then, by means of a strong heavy rake with a wooden head, ten inches in length, & iron teeth about two inches and a balf long, gather off the stones to the side of the road, to be broken there; but, on no account, on the road itself, agreeably to the directions already given. All the stones which exceed six ounces being thus removed, the road must be put into shape, and the surface smoothed by the rake; and then the newly-broken stones are to be replaced on the road, and consolidated, as already directed. When ten inches of clean stones are found in the old road, no new materials will be needed; and, if there be a smaller quantity, as many new stones should be brought forward and laid on as will make up that thickness.

A small space of road only, as two or three yards all across, should be lifted at once, and that should be re-laid before another piece is lifted. The complement of hands usually

required, is five persons; two picking-up and raking, and three breaking, stones. The spring is the proper season for this operation.

Roads made of gravel, or of soft stones, do not admit of being new-modelled by lifting, neither will the above directions apply to the case of a road much out of shape, or in very great disorder.

7. Management.---So much depends upon the proper remedy being applied to each particular road, and to each part of a road, and it is a matter of such difficulty precisely to determine, in every case, what that remedy ought to be, that the introduction of the system thus proposed cannot, with any prospect of success, be attempted, without the appointment of a general surveyor, of respectable rank and character, and of liberal education, previously instructed in the principles and practice of road-making.

AMERICAN WRITERS.

Extracted from Blackwood's Edinburgh Magazine, Feb. 1820.

ON THE WRITINGS OF CHARLES BROCKDEN BROWN AND WASHINGTON IRVING.

IF F we may judge from an article in the twenty-fifth number of the North American Review, which has just come into our hands, a great deal of wrath has been very needlessly and absurdly excited among our readers on the other side of the Atlantic, by two articles on the state of education and learning in the United States,* which appeared some time ago in this Miscellany. The critic who has honoured us so far as to make these papers the subject of a very elaborate review, has not, we think, succeeded in pointing out any very important inaccuracies in the facts we mentioned; and if the conclusions at which he has arrived be rather more favourable than ours, we can only say, that we most heartily hope he is in the right, and we in the wrong. To prevent mistakes, however, we must inform him, that his suspicions concerning British Manufacture' are entirely unfounded. The papers on which he has commented were altogether written by a countryman of his own-a young gentleman of very extraordinary talents, whose attainments, when he first reached Europe, did great honour to the trans-atlantic seminaries in which he had received his education-and who has now, we believe, returned to America,improved by several well-spent years of travel and of study, in a condition to See Ath. vol. 5, p. 129.

render important services to the common literature of his own country and of ours.

Our American critic complains, that the productions of Americah genius are never received as they ought to be by the people of England, that a certain strange mixture of haughtiness, jealousy, and indifference, is manifested on every occasion when any American author forms the subject of professional criticism in Britain-while to our reading public at large, even the names of some men whose writings do the highest honour to the language in which they are written, remain at this moment entirely unknown. In so far, we are free to confess, that we think our countrymen do lie open to this last reproach. The great names of which we are ignorant, cannot indeed be numerous, for few American writers are ever talked of, even by Mr. Walsh or the North American Review itself, with whom we think people on this side the water are less acquainted than they ought to be. In truth, so far as we know, there are two American authors only, whose genius has reason to complain of British neglect and with a very great deal of reason both unquestionably may do so -namely, Charles Brockden Brown and Washington Irving.

The first of these has been dead for several years; and the periodical works,