THE engine of which an engraving is annexed is thus described by the inventor, Oliver Evans, of Philadelphia. My principle is to confine and retain the steam, and, by that means, encrease the heat in the water, which encreases the elastic power of the steam in a rapid ratio, to a great degree, by a very small encrease of the consumption of fuel: namely, as the heat of the water is increased in an arithmetical progression, the elastic power of the steam increases in a geometrical progression. Every addition of about thirty degrees of heat to the water, by Fahrenheit's thermometer, be the temperature what it may, doubles the elastic power of the steam, so that doubling the heat in the water increases the elastic power of the steam about a hundred times. Similar ratios hold good in practice; every addition of a small quantity of fuel doubles the power and effect of the engine, so that doubling the fuel produces about sixteen times the ef

VOL. III. NO. XIX.

fect, which enables us with small, simple, and cheap engines to produce effects equal to larger, more complex, and expensive ones, heretofore used, with about one-third part of the fuel: which renders them useful for a great variety of purposes for which other engines would be unprofitable, as they can be constructed at half the expence to produce equal power, and are from five to ten times as powerful, according to their size and weight. The power can be doubled or tripled at pleasure, to meet extra resistances, and may be kept in reserve until wanted; which qualities render the engines applicable to and suitable for all the following purposes, and profitable in each case, where water-falls are not to be had, viz. for grinding all kinds of grain, sawing of all kinds of timber, raising of water for draining of mines, watering of cities or lands, driving of sugar-mills, working of rolling and slitting-mills, forge hammers, or

1

bellows for furnaces, chopping grain and pumping water for distilleries and breweries: where the steam, after it leaves the engine, may be applied to heat the water, and save fuel; to turn grinding stones, turning lathes to grind coffee, chocolate, paints, bark, &c., to propel boats against a current, and waggons on turnpike roads; in short, for every purpose for which power may be wanted, from the power of one man, to that of one hundred horses.

I am preparing for the press a small work, explaining the principles, and showing the reasons why they produce such wonderful effects; but to do justice to this subject would require a large and very expensive volume, which I had began, but have relinquished, believing the sales would not defray the expense. The Plate represents a plain elevated section of the different parts of the engine, connected in the operation, but they are differently arranged in the construction.

EXPLANATION.

a The end view of the boiler, consisting of two cylindrical tubes, the best form for holding a great power, the lesser inside of the great

er.

The fire is kindled in the inner one, which serves as a furnace, the water being between them. The smoke passes to the other end, is turned under the supply boiler, b, to heat the water for supplying the waste occasioned by working; c the supply pump, which brings water up, and forces it into the supply boiler, at every stroke of the engine.

The steam ascends the pipe, and if the throttle valve d be lifted to let the steam into the engine, and valves e and ƒ be opened, the steam drives the piston g to the lower end of the cylinder, as it appears in the plate. The steam escaping before the piston through the valve f, as soon as the piston is down the valves ef shut and h i open, the steam enters at h to drive the piston up again, and escapes before the piston

Thus

through the valve i. These four valves are wrought by two wheels, kl, with cams on their sides, which strike against four levers, not shown in the plate, to which the stems of the valves are attached, and which open and shut them at the proper time. The motion of the piston g gives motion to the lever m n, and the rod m o, connected to the crank, puts it in motion, and the fly wheel qr keeps its motion regular, the spur wheels & t, of equal size, move the valve wheels / k; the lever m n works the supply pump c. the motion is continued, and the cog wheel v of 66 cogs going into the tunnel u of 23 cogs, gives the stone w 100 revolutions per minute, when the piston strikes 35 strokes. This cog wheel may move any other work, or instead thereof a crank may move a pump or saw, as this engine may be made to strike from 10 to 100 strokes per minute, as the case may require; and if the working cylinder be 8 inches diameter, it will drive a pair of five feet millstones, or other work requiring an equal power.

The steam, after it leaves the engine, escapes up the pipe x x, through the roof of the house, or into a condenser, if one be used, or through the supply boiler to heat the water. A safety valve, kept down by a lever graduated like a steelyard, to weigh the power of the steam; this valve will lift and let the steam escape, when its power is too great.

If the pipe of the safety valve be turned into the flue of the furnace, then, by lifting the valve, the ashes may all be blown out of the flue.

This engine is of a simple construction, easily executed by ordinary mechanics: the valve seats are formed by simple plates, with holes in them, easily cast.

In working this engine to drive ten saws, we find, that if we put her in motion as soon as she has power to drive one saw, and suffer her to move briskly, she carries off the heat from the boiler nearly as fast as it is generated, and fuel may be

consumed and time spent to little purpose; but if we confine and retain the steam in the boiler, until it lifts the safety valve with a power sufficient to drive ten saws, she will start with that load, and carry it all day, and consume but little more fuel.

It takes up but little room in the building. The draught is drawn from a scale of half an inch to a foot, except the millstones, and two wheels that move them. They are a quarter of an inch to a foot.

For the Literary Magazine.

NAVAL TRANSACTIONS IN THE

MEDITERRANEAN.

THE most considerable naval transactions in which the United States have been engaged, since the revolution, are, undoubtedly, those that have lately taken place in the Mediterranean. They form, therefore, the most important portion of our national history, in our relation to other states. The following account has a better chance of being a circumstantial and authentic narrative of these transactions than is elsewhere to be met with. It is drawn up from the commodore's official dispatch, and contains the account of his proceedings during one month, from the 10th of August to the 10th of September, 1804.

The commander was detained by bad weather in the harbour of Messina, till the 9th of August, when he left it with two small bomb vessels under convoy, and arrived at Syracuse, where he was necessarily detained four days. On the 14th he sailed; the schooners Nautilus and Enterprize in company, with six gun boats and two bomb vessels, placed under his command by the king of Naples. The bomb vessels were about thirty tons, carried a thirteen inch brass sea mortar, and forty men. The gun boats were twenty-five tons; carried a long iron twenty-four pounder in the

bow, with thirty-five men. They were officered and manned from the squadron, except twelve Neapolitan bombardiers, gunners, and sailors attached to each boat, who were shipped by permission of their government. This step was found necessary, as every vessel in the squadron was considerably short of her complement.

The gun boats are constructed for the defence of harbours; they are flat bottomed and heavy, and very badly sail and row. They were never intended to go to sea, and cannot be navigated with safety, unless assisted by tow-ropes from larger and better sailing vessels; nor even then, in very bad weather. However, as they were the best to be had, he thought proper to employ them, particularly as the weather in July and August is generally serene, and without them his force was too small to make any impression on Tripoli.

On the 16th of July they arrived at Malta, where they were detained by contrary gales till the 21st, when they left it, and arrived in sight of Tripoli the 25th, and were joined by the Siren, Argus, Vixen, and Scourge. The squadron now consisted of the Constitution, three brigs, three schooners, two bombs, and six gun boats; the whole number of men 1060. He proceeded to make the necessary arrangements for an attack on Tripoli, a city well walled, protected by batteries judiciously constructed, mounting 115 pieces of heavy cannon, and defended by 25,000 Arabs and Turks; the harbour protected by 19 gun boats, two gallies, two schooners, of eight guns each, and a brig mounting ten guns, ranged in order of battle, forming a strong line of defence at secured moorings, within a long range of rocks and shoals, extending more than two miles eastward of the town. This reef forms the harbour, and protects it from the northern gales. It is hence impossible for a vessel of the Constitution's draft of water to approach near enough to destroy them, as they are