mine can't, I assure you!" Ellen smiled, spite of herself, with pride and pleasure too, for this admirable creature loved her, even though she loved another. Again she was absent and taciturn, while Mrs. Ainslie, wishing her to be left to her own reflections, made no effort to engage her in conversation.

Never had Ellen been so absorbed in the business of the toilet as she was to-day. Mrs. Ainslie kindly superintended and patiently answered all Ellen's inquiries, as to what was fashionable, rather than as to what was becoming; for she had discovered that fashion was every thing with Mandeville. At length not satisfied with her appearance, for her aim was to recall a strayed heart, and love makes every one humble, Ellen, attired entirely to the satisfaction of Mrs. Ainslie and to the loud admiration of Mr. Ainslie, seated herself on a sofa that held only two, and with a beating heart awaited the arrival of Charles, for she could not help hoping, spite of all that had passed, that he would come early; but he came last, and was evidently not solicitous to sit next Ellen at table. Mrs. Ainslie, however, conscious that Ellen would be evidently disconcerted if he did not sit by her, desired Ellen to go next him, as he, of course, sat by the lady whom he had handed down stairs, and she tried to be happy. But Charles did not, as he used to do at R, turn his back for her sake on the lady, whoever she was, that sat on the other side of him, and she felt glad when the ladies retired, that she might go to her own room, and relieve her full heart by weeping.

FROM THE EDINBURGH PHILOSOPHICAL JOURNAL.

Description of Mr. Perkins's New Steam-Engine, and of the application of his Invention to Engines of the Old Construc

tion.

We have already communicated to our readers in the two last numbers of this Journal, all the authentic information which we could obtain respecting Mr. Perkins's new Steam-Engine; and we have used the utmost diligence to obtain such farther information as may, in some measure, gratify that curiosity which these imperfect notices have excited. There never has been in our day an invention which has created such a sensation in the scientific and in the manufacturing world. The steam-engine of Mr. Watt had been so long considered as the greatest triumph of art and science, that it was deemed a sort of heresy to regard it as capable of improvement; and, notwithstanding all that has been done by Mr. Woolff, and other eminent engineers, the undoubted merit of their engines has scarcely yet been admitted by the public. Under such circumstances, Mr. Perkins's claims were likely to meet with various kinds of opposition. Instead of hailing it as an invention which was to do honour to the age in which we live, and to add a new and powerful arm to British industry, imperfect experiments and confined views were urged against the principle of its construction, the jealousies of rival traders were arrayed against it, imaginary apprehensions of danger were excited, and short-sighted politicians sounded the alarm, that such an invention would precipitate our country from its lofty pre-eminence among the manufacturing nations of the world.

Most of these grounds of opposition have been now removed by direct experiment. Mr. Perkins's engine is actually at work. Its operations have been witnessed, and minutely examined by engineers and philosophers of all kinds; and the most unreasonable sceptics have been compelled to acknowledge the justness of its principles, as well as the energy of its operations. The active and inventive mind of Mr. Perkins, however, did not remain satisfied with this experiment. He has discovered a method, which we consider equal in value to his new engine, by which he can convey the benefit of his original principle to steam-engines of the old construction; and this has been recently succeeded, we are told, by a most extraordinary discovery, that the same heat may be made to perform its part more than once, in the active operations of the engine. In order to convey to our readers some idea of these great inventions, we have obtained a drawing, made by M. Montgolfier, jun. and given in the Plate, which, though it does not represent the actual machine, yet contains such a view of its parts as is necessary for understanding its principle.

The generator, which supplies the place of the boiler in ordinary steam-engines, is a cylinder ABCD, made of gun-metal, which is

more tenacious, and less liable to oxidation, than any other. The metal is about three inches thick; and the vessel, containing eight gallons of water, is closed at both ends, with the exception of the five openings for tubes, shown in the figure. The generator is placed vertically in a cylindrical furnace EF, whose chimney is G, the heat being sustained by a pair of bellows H, wrought by the engine, and conveying its blast in the direction IK to F. A heat of from 400° to 450° of Fahrenheit is thus applied to the generator, which is entirely filled with water. The valves in the tubes m, n, which are steel cylinders working in hollow steel-pipes, are loaded, the one with 37, and the other with 35 atmospheres; so that none of them can rise till the heat creates a force greater than the least of these weights.

Let us now suppose, that, by means of the compressing pump L, whose handle M is wrought by the engine, water is forced into the generator; this opens the valve above n, loaded with 35 atmospheres, and instantly a portion of the heated and compressed water flashes out in the form of steam of high elasticity, and of a temperature of 420°; and communicating by the steam-pipe 2, 2, 2, with the valve-box V, it enters the cylinder PP, lying horizontally, and gives motion to its piston PQ, which performs 200 strokes in a minute, and drives a crank R, which gives a rotatory motion to a fly-wheel, as seen in the figure. When the eduction-valve is opened, the steam, after having produced its stroke, is carried by the eduction-pipe 3, 3, 3, into the condenser STXV, where it is condensed into water at a temperature of about 320°, and under a pressure of 5 atmospheres; from thence, by the pipe 6, 6, 6, it is drawn into the pump L, whence it is forced along the pipe 4, 4, 4, to the generator, thus performing a complete circuit.

The forcing-pump acts with a pressure exceeding 35 atmospheres; consequently, when the water received in it from the condenser is urged into the generator, it must expel a portion equal to itself in volume: this portion, as above described, flashes instantly into highly elastic steam. The forcing-pump, too, is so contrived as to act with a steady force, and, consequently, the expelled water must be driven from the generator in a steady current, and thus steam of a constant elasticity is supplied to produce the power.

Some philosophers are of opinion, that the heat of the portion of water which escapes, is of itself sufficient to maintain the steam at that high degree of heat and elasticity with which it reaches the piston; and, consequently, that this engine is nothing more than a High Pressure Engine. Other persons, however, have supposed, and we confess we are among that number, that the portion of water which escapes, must necessarily carry off a quantity of heat from the adjoining stratum (the temperature of which may be thus reduced below the freezing point). But it is more likely, that, in

*The parallel motion represented at PQ, is not the correct one used by Mr. Perkins. The piston-rod is connected by a flexible joint, with a sort of carriage with four wheels at each end, and working in a strong horizontal box of steel.