seems written on all around him. He who has been privileged, on the Sabbath, to strive to bring some wandering souls to Christ, has experienced the happiness of committing them to him at its close, and leaving their welfare to his infinite compassion. How sweet is it to read, in the course of the seasons, and the abundance that crowns them, the bounty of that Lord who sustains the tribes of earth. This is he who careth for souls, and "willeth not that any should perish, but that all should come unto him and live."

A blessing, worthy of the liberality of the King of Kings, has been provided to the observance of the Sabbath, "Ye shall keep my Sabbaths, and reverence my sanctuary; and I will set my tabernacle among you; and I will walk among you; and I will be your God, and ye shall be my people." There is not one among the children of God who will not testify that, "in the keeping of this commandment, there is great reward." In proportion as the Sabbath is improved, will each day resemble a Sabbath, in being employed for God, and spent in the frame of spirit which most resembles that of the blessed beings who keep a perpetual Sabbath around the throne. Let not the people of God think lightly of his day. Its early morning should witness the devotion of the thirsting soul. Its hours, as they pass in the closet, or the sanctuary, should all be full of God. There is enough in the wonders of redeeming love to fill the minds of angels. Surely, then, more than enough to engross the best affections of those on whose behalf that love was manifested. The longer it is thought of, the more impossible does it appear that the heart of man can ever understand or value it, according to its exceeding price.-The beauties that shine in the countenance of the Redeemer shall be gazed on with unwearied transport through eternity. How gladly, then, should those seasons be welcomed, that afford the best opportunities for looking on them from afar. To him who does thus look, they are revealed faint and dim, compared with what they shall be, yet with a ce

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lestial brightness which makes all earthly light grow pale and fade; and, as he fixes his steadfast gaze, the face of the beholder shines, and he is transformed into a nearer resemblance to Jesus, the friend whom his soul loveth. With such a friend at hand, and heaven in prospect, the fading rays of evening are full of beauty; for they point to the coming dawn of a morning without clouds." The gradual change from the laden bough and the yellow harvest, to the leafless tree, and stripped and barren earth, are perceived, not with sadness, but with cheerful hope; for years are ever passing, and ever bringing nearer the great and final change; and, when the seed, sown by the heavenly husbandman, shall, under the constant influences of his sun and showers, have yielded fruit to his glory, he will gather it into his garner. All the chaff that mingles with it now, shall be separated, for nothing that defileth can be admitted there. But not one grain of wheat, however small, shall be dispised or lost; for each is precious in the sight of him who sowed and ripened it; and that which is, in itself, of no value, shall, by his wonderful power, become a fair and luxuriant plant, that shall flourish for ever in the paraM. L. D.

dise above.

TWELFTH WEEK-MONDAY.

PROSPECTIVE IMPROVEMENT OF LOCOMOTIVE POWER.-ROTARY STEAM ENGINE-ELECTRO-MAGNETIC ENGINE.

THE practice of locomotion, by means of steam, is yet in its infancy, and in this age of invention we need not be surprised to find men of ingenuity actively employed in attempts to discover new and more useful modes of applying this wonderful power to an object of so much importance. The chief defect of the steamengine, in its present form, as applicable to locomotion, consists in the necessary weight and bulk both of the

machinery itself, and the coals and water required for the boilers. This is a disadvantage which, though not felt in stationary engines, forms so great an impediment to the locomotive principle, that any scheme by which it could be obviated or diminished, while other properties should remain the same, could not fail to be regarded as highly important.

The weight of the requisite machinery is chiefly owing to the complicated apparatus connected with the movement of the pistons. A plan for dispensing with the pistons altogether, and thus greatly simplifying the mechanism, has lately been adopted, with apparent success, in America, by recurring to the method by which the power of steam was originally, and at a very early period, employed in the direct production of rotary motion. Should this power be found, when tried on a large scale, to answer the sanguine expectations of its advocates, a most desirable saving would be effected in the weight and complicated nature of the mechanism.*

This mode of applying steam-power, however, would

*I allude to Avery's rotary steam-engine, which was first rendered available for moving machinery in America, and has very recently been introduced into this country by Mr Craig of Edinburgh. This engine is formed on the principle which was invented by Hero of Alexandria, so far back as the second century before the Christian era; but it has never, till now, been considered possessed of sufficient power to be employed for any useful purpose. The machinery of the moving power is very simple. consists of a hollow tube revolving on a spindle. Through this spindle the It steam enters, and passing along each arm of the tube, issues at the extremity from an orifice in the side. The effect of this is to cause a revolving motion in the arms, which may be increased till the velocity with which they move equals that with which the steam issues from the orifices. The force is then at its maximum, and, when this speed is gained, the steam, as it issues, remains stationary; and, therefore, the whole power of the steam has been transferred to the arms.

The principle of this engine has been greatly misunderstood. It was formerly supposed that the motion was produced by a re-action of the steam upon the atmosphere. It has now, however, been satisfactorily proved that the steam presses internally upon the side of the arm opposite the orifice when the arms are stationary, with a force equal to twice its pressure on any other equal surface,—with an equal pressure when the arms are revolving with the same velocity as the steam,-and that there is no pressure when they revolve with double the velocity.

A very simple addition to this engine has been invented by a gentleman in Edinburgh, by which the power is greatly increased, and the friction

scarcely affect the quantity of coals and water which must be consumed in generating it; and, indeed, so long as steam is resorted to as the impelling agent, we can expect no great diminution in the use of these articles. But there are in nature other agents of tremendous force, to which, could they be made subservient to the will of man, a similar objection would not apply; and it is by no means chimerical to suppose, that human ingenuity has as yet only touched on a territory where elements of power remain to be developed capable of a far more extensive and useful application than any hitherto employed.

In making this observation, I particularly allude to the very recent discovery of a method of applying to machinery a power generated through means of magnetism—an agent hitherto regarded more as a subject of curious experiment, than as possessing any mechanical value; and since it already seems possible that at no distant date this invention may be generally adopted in many cases in which steam-power is now used, and especially for the purposes of locomotion, it may not be deemed superfluous to devote the remainder of this paper to so interesting a subject.

An artificial magnet need hardly be described. It consists of a bar of iron or steel, which having been subjected to a certain well known process, acquires the property, when suspended horizontally by a single fibre of untwisted silk, or nicely balanced on a pivot, of arranging itself, after a few oscillations, in a direction nearly north and south, the ends being in consequence denominated respectively the north and south poles of the magnet. If we suspend two such bars near each other, it will be seen that the poles in each, which bear the same name, and which, when the magnets were separate, pointed the same way, repel each other with violence, greatly diminished. This is the attachment of a condenser to the drum, or case, in which the arms revolve. By this means the arms are made to revolve in a vacuum, so that the resistance of the atmosphere is removed. Their power is by the same means increased to an extent equal to what would be obtained by an increase of 15 lbs. in the pressure of the steam.

while the north pole of the one strongly attracts the south pole of the other, and vice versa.

It is not necessary, however, that these bars should always be straight. They are often bent into the form of a horse-shoe or semicircle, and in this shape they retain the properties of attraction and repulsion which have just been noticed. It is by means of such magnets that one of the simplest examples of the mechanical application of the principle I have mentioned, has been exhibited ; and in the following manner :-Fix two semicircular magnets horizontally in the same plane, so that the north and south poles of the one shall be opposite to the south and north poles of the other respectively, and at the distance of about an inch. Suspend in the interval between them a bar magnet of sufficient size, and observe the position it will take. It will immediately be attracted by the fixed magnet, whose north and south poles are nearest to its own south and north poles, and will cling to it with a force proportioned to the power of the magnet. Next reverse the position of the semicircular magnets, by turning them simultaneously, so that their north poles shall change places with their south poles; the bar will of course undergo a corresponding change. By the aid of a substantial wooden pendulum, into which the bar is fixed, and which is nicely hung on knife edges, a reversing apparatus may be worked, and, when the machine is once set agoing, it will continue to act, the bar being driven from one magnet to another with the velocity of two or three hundred vibrations in a minute.

Such an application of magnetism, however, we might despair of rendering effective for mechanical purposes, the power being small, and the mode of working inefficient.

I have now, however, to state a method which has lately been discovered, of exciting magnetic power to a much greater degree than has ever been effected by the permanent or simple magnet, and in a way much more