It will be always necessary to caution painters to keep their utensils, brushes, &c. very clean, as the colour would otherwise soon become very foul, so as to destroy the surface of the work. If this should happen, the colour must be passed through a fine sieve, or canvass, and the surface of the work be carefully rubbed down with sand-paper, or pumicestone the latter should be ground in water, if the paint be tender, or recently laid on. The above may suffice as to painting on wood, either on inside or outside work, the former being seldom finished otherwise than in oil: four or five coats are generally sufficient.

It does not appear that painting in oil can be serviceable in stucco, unless the walls have been erected a sufficient time to permit the mass of brick-work to have acquired a sufficient degrec of dryness. When stucco is on battened work, it may be painted over much sooner than when prepared on brick. Indeed, the greatest part of the art of painting stucco, so as to stand or wear well, consists in attending to these observations, for whoever has observed the expansive power of water, not only in congelation, but also in evaporation, must be well aware that when it meets with any foreign body, obstructing its escape, as oil painting, for instance, it immediately resists it, forming a number of vesicles or particles, containing an acrid lime-water, which forces off the layers of plaster, and frequently causes large defective patches, not easily to be eradicated.

Perhaps, in general cases, where persons are building on their own estates, or for themselves, two or three years are not too long to suffer the stucco to remain unpainted, though frequently, in speculative works, as many weeks are scarcely allowed to pass.

The foregoing precautions being attended to, there can be no better mode adopted for priming, or laying on the first coat on stucco, than by linseed or nut-oil, boiled with dryers, as before mentioned; taking care, in all cases, not to lay on too much, so as to render the surface rough and irregular, and not more than the stucco will absorb. It should then be covered with three or four coats of white-lead, prepared as described for painting on wainscotting, allowing each coat a sufficient time to dry hard. If time will permit, two or three days between each layer, will be advantageous. When the stucco is intended to be finished in any given tint, as grey, light green, &c. it will then be proper, about the third coat of painting, to prepare the ground for such tint, by a slight advance towards it. Grey is made

with white-lead, Prussian-blue, ivory-black, and lake; sagegreen, pea, and sea-greens, with white, Prussian-blue, and fine yellows; apricot and peach, with lake, white, and Chinese vermilion; fine yellow fawn colour with burnt terra sienna, or umber and white; and olive-greens with fined Prussian-blues, and Oxfordshire ochre.

Distemper, or painting in water colours, mixed with size, stucco, or plaster, which is intended to be painted in oil when finished, but not being sufficiently dry to receive the oil, may have a coating in water colours, of any given tint required, in order to give a more finished appearance to that part of the building. Straw colours may be made with French whites and ceruse, or white lead and masticot, Dutch pink. Greys, full, with some whites and refiner's verditer. An inferior grey may be made with blue-black, or bone-black and indigo. Pea-greens with French green, Olympian green, &c. Fawn-colour with burnt terra d sienna, or burnt umber and white, and so of any interme diate tint. The colours should all be ground very fine, and mixed with whiting and a size made with parchment, some similar substance. Less than two coats will not be sufficient to cover the plaster, and bear out with an uniform appearance. It must be recollected, that when the stucco is sufficiently dry, and it is desirable to have it painted in oil, the whole of the water-colours ought to be removed, which may easily be done by washing, and when quite dry proceed with it after the direction given on oil-painting in

stucco.

If old plastering has become disfigured by stains, or other blemishes, and it be desired to have it painted in distemper, it is, in this case, advisable to give the old plastering, when properly cleaned off and prepared, one coat, at least, of white-lead ground in oil, and used with spirits of tur pentine, which will generally fix old stains; and, when quite dry, take water-colours very kindly.

MENSURATION OF PAINTERS' WORK.

Painters' work is measured by the yard square, and the dimensions are taken in feet, inches, and tenths. Every part which the brush has passed over is measured, conse quently the dimensions must be taken with a line, that girts over the mouldings, breaks, &c. All kinds of ornamental work produces an extra price, according to the nature of the imitations, &c. Carved work is also valued according to the time taken in painting it

RAIL-ROADS

AND

LOCOMOTIVE ENGINES.

AMIDST the various speculations of the day, perhaps none have more deservedly excited the public interest than that of the numerous projected lines of rail-road for diminishing the friction of carriages, and for propelling carriages on them by either gas or steam power.

The lessening the friction, produces a consequent diminution in the power which otherwise would be required to propel a given weight; and therefore, is, in a commercial nation, like that of the united kingdom, a subject worthy of the highest consideration.

Railways were originally made of wood, and appear to have been first introduced between the river Tyne and some of the principal coal-pits, as early as the year 1680. The scarcity of this material, and the expense of frequent repairs, soon suggested an idea that iron might be more advantageously employed. At first, flat rods of bar-iron were nailed upon the original wooden rails, or, as they were technically called, sleepers; which, though an expensive - process, was found to be a great improvement. But as the wood on which these rested was liable to rot and give way, these railings were soon after superseded by others made entirely of iron.

These tram or rail-roads have, for a considerable length of time, been much used in the colliery and mining districts; and some few have been carried from one town or manufacturing district to another. The principal of these latter in England and Wales are, the Cardiff and Merthyr, 26 miles long, running near the Glamorganshire canal; the Caermarthen; the Lexhowry, 28 miles, in the counties of Monmouth and Brecknock; the Surrey 26 miles; the Swansea, 7 miles; one between Gloucester and Cheltenham; besides several in the north of England.

Railways are of two kinds, arising from the disposition of

the flanch that is to guide the wheels of the carriage, and prevent it from running off the rail. In the one, the flanch is at right angles, and of one piece with the flat surface of the rail: in the other, the flat surface of the rail is raised above the level of the ground, and the flanch is fixed on the wheel of the carriage, at right angles to the tyre, or iron placed on the circumference of the wheel, to strengthen it. Beside these, another kind of railway has lately been intro duced by Mr. Palmer, which consists of a single rail, supported some height from the surface of the ground: on this, two wheels confined in sufficient frame-work, are placed, suspending the load equally balanced on either side. This arrangement certainly seems to ensure the grand principl of lessening friction, and doubtless will, in many situations, be found a great improvement.

Previously to entering upon the probable advantages like ly to result from a general introduction of railways, w shall give the substance of the specification of a patent, ob tained in Sept. 1816, by Messrs. Losh and Stephenson, bott of whom are well known to those interested in the subject. These gentlemen preface a description of their method of facilitating carriages along tram and railways, with an ob servation, that there are two kinds of railways in genera use; the one consisting of bars of cast iron, generally of the shape of that described by a, fig.631, the other of the shape of that described by figs. 630 and 631. That shewn at 6, fig. 629, is known in different situations by the denomina tion of the edge rail, round-top rail, fish-backed rail, &c That shewn at figs. 632 and 633, by the denomination of the plate-rail, tram-way plate, barrow-way plate, &c. The first we shall distinguish by the name of the edge railway; the second, by that of the plate railway.

In the construction of edge railways, Messrs. Losh and Stephenson's objects are, first, to fix both the ends of the rails, or separate pieces, of which the ways are formed, immovable, in or upon the chairs or props by which they are supported; secondly, to place them in such a manner that the end of any one rail shall not project above or f below the correspondent end of that with which it is in con tact, or with which it is joined; thirdly, to form the joinings of the rails, with the pedestals or props which support them, in such a manner, that if these props should vary from their perpendicular position in the line of the way (which in other railways is often the case) the joinings of the rails with each other would remain as before such varia

tion, and so that the rails shall bear upon the props as firmly as before. The formation of the rails or plates of which a plate railway consists, being different from the rails of which the edge railways are composed, they are obliged to adopt a different manner of joining them, both with each other, and with the props and sleepers on which they rest. But in the joining these rails or plates upon their chairs and sleepers, they fix them down immovably, and in such a manner that the end of one rail or plate does not project above, or fall below the end of the adjoining plate, so as to 6 present an obstacle, or cause a shock to the wheels of the carriages which pass over them, and they also form the joinings of these rails or plates in such a manner as to prevent the possibility of the nails, which are employed in fixing them in their chairs, from starting out of their places from the vibration of the plates, or from other causes.

In what relates to the locomotive engines and their carriages, which may be employed for conveying goods or materials along edge railways or plate-railways, or for propelling or drawing after them the carriages or waggons employed for that purpose, their invention consists in sustaining the weight, or a proportion of the weight, of the engine, upon pistons, movable within cylinders, into which the steam or the water of the boiler is allowed to enter, in order to press upon such pistons; and which pistons are, by the intervention of certain levers and connecting rods, or by any other effective contrivance, made to bear upon the axles of the wheels of the carriage upon which the engine rests. In the formation of the wheels it is their object to construct them in such a manner, and to form them of such materials, as shall make them more durable and less expensive in the repairs than those hitherto in use. This is accomplished by forming the wheels either with spokes of malleable iron, and with cast iron rims, or by making the wheels and spokes of cast iron, with hoops, tyres, or trods, of malleable iron, and in some instances, particularly for wheels of very small diameters, instead of spokes of malleable iron, employing plates of malleable iron, to form the junction between the naves and the cast iron rims of the wheels.

The advantages gained by this method of constructing railways are, first, that the separate pieces of which they consist are, cæteris paribus, rendered by this mode of joining them, capable of sustaining a much heavier pressure than those which are joined in the usual way. Secondly, by this