ONE hundred and twenty years before the Christian era, a wheel, driven by a jet of steam, revolved in the Egyptian capital. More than nineteen centuries succeeded, marking their deep furrows upon the broad face of creation, before this whirling toy ripened into the mighty Steam Engine, now so familiar to our race. During this vast period of time, sixty generations of men were born, and lived, and garnered for eternity. Of all the millions composing these generations, no man had appeared ingenious enough to drive pistons to and fro with that vapor, which had turned the playful wheel in Alexandria. That which now seems to have been its obvious application, nearly two thousand years were consumed in finding out. It required but a cylinder, a piston to move within it, grasping a crank, and with but few and simple contrivances beyond, the steam-engine was complete. That power which had created a rotary motion, could produce a reciprocating motion. To establish this neither experiment nor scientific learning was necessary; and if these had been required, both could have been abundantly supplied. Great geniuses had appeared, and scattered their rich gifts among men, and had passed away; failing to accomplish that which Watt finally completed. Human skill had multiplied luxuries, human invention had created innumerable comforts; but still mankind were as destitute of a Motive Power as when the Israelites journeyed from Egypt. At the end of the eighteenth century this power appeared. At length it assumed a form which enabled it to drag heavy burdens upon land and sea; and then, as the grim monster blew its hot breath from its iron lungs, the globe seemed contracted to half its former size.

In strength it was mightier than any moving thing, and in speed it rivaled the birds of heaven. It has become the strong carrier and the fleet

racer.

Glowing fires are its food, and its sinews hot vapor. Its unearthly shriek troubles the air, and its rolling tramp shakes the earth. It impels huge ships over wide seas; defying the hurricane and mastering the storm. It digs the ore, blows the furnace, wields the heavy hammer, and turns the spindle. It toils in the workshop; it toils in mid ocean, and it toils as it bounds along upon its iron track, unchecked by its ponderous train. It has traversed mighty waters, walked upon dark and troubled seas, darted through tunneled mountains, and coursed along western wilds.

Its years have been few. The nineteenth century dawned upon its early infancy, and the first half of that century closed upon its gigantic manhood. In this short period of time, it has stamped new and everlasting characters upon the history of mankind. It has accomplished a grand, and we believe its final destiny. We think its end is at hand, its mission nearly over. If it has been a useful slave, it has also been a costly and dangerous one.

To prevent this danger, the most watchful care, the profoundest skill, have proved unavailing. If the slaughter of our race, caused by its bursting boilers could be presented to view, humanity would stand appalled. Its course has been marked and its onward track strewn with mangled bodies.

Of this the press, day by day, tells an awful story.

It is time that this fierce and expensive, though mighty bond-servant, should be replaced by one equally powerful, cheaper, and less dangerous. The age is ripe for this change. The experience of the last few years has determined that steam cannot be profitably used, for commercial purposes, upon the ocean. For a voyage of three thousand miles, a large portion of the freighting capacity of the ship is required for coals alone. These, with the engine and huge boilers, occupy a part at least of that space, which should be filled with merchandise. The expense of the coal consumed is enormous; but this could be borne if it occupied less room. In proportion as the voyage is extended, does steam, as a motive power, become more expensive; until finally, the entire ship would be insufficient to contain the fuel necessary to feed the engine. A steamer of the Collins line consumes, we are informed, about one thousand tons of ccal for a voyage of three thousand miles. Double this distance, and although the cost of the coal is but doubled, nearly the entire freighting room of the steamer is absorbed by it, and her power to earn freight is gone. Still increase this distance, with no means to supply fuel upon the route, and steam machinery becomes worse than useless. The broad Pacific cannot be traversed by it. Its rich commerce invites the merchant ship, and rewards the navigator, but the steamer must hug its shores, and cannot profitably explore its ample bosom. It is the mission of man to hold the earth and its waters in subjection by machinery. By machinery he is destined to lighten the drudgery which at the dawn of creation fell upon his race. To accomplish this he has been endowed with genius and inventive power; and where the force of a thousand giants would be fruitless, these triumphantly prevail. They gave to the world steam as a motive power. It has proved inadequate to the wants of men, destructive to human life, and more costly than the interests of commerce can sustain.

A new motive power is demanded, and if the eyesight and the judgment can be relied upon, it has appeared. It is the most sublime development of force ever seen in machinery! It is exerted by that life-giving, elastic fluid, the atmosphere. It is drawn from that vast magazine through which the lightnings play, and is supplied from that unseen element which

sighs in the breeze and roars in the hurricane. We are not intimately acquainted with machinery, nor are we altogether ignorant of the principles of mechanical science. We know enough of both to form an intelligent judgment concerning the wonderful machine to which we allude, and which we have carefully examined. It is not, like most new inventions, presented in a mere model. It does not, like most new inventions, rest in bare experiment. Were these its conditions, the Merchants' Magazine would express no judgment concerning its utility, nor indulge in any speculations as to its supposed value. We should leave this talk to those who are supposed to be better acquainted with the science of mechanics, and with the practical value of untried inventions, than the editor of a commercial journal. We are not here called upon to perform this task.

A celebrated painter has said "Let my productions be subjected to the judgment of the whole world, but heaven deliver me from that of my own profession." This may not, in a majority of cases, prove to be a just apprehension; but it is quite certain that there is in every profession a conservative spirit, which clings to the knowledge of the past, and distrusts that which is new and untried. This is strikingly illustrated in the case of the steam-engine.

We all know that, at this time, the only mode in use for producing a rotary motion, from the reciprocating motion of the piston of a steam-engine, is by means of a crank. It is equally well known, that to enable the sta tionary engine to "pass the center," a ponderous fly-wheel is employed. Now it will hardly be credited, that both these methods were at first condemned by distinguished engineers, as utterly impracticable. In 1777 Mr. Stewart read a paper before the Royal Society in London, describing a method for obtaining a continued circular motion, for turning all kinds of mills, from the reciprocating motion of the steam-engine. This he proposed to effect by means of a complicated contrivance, which practice soon proved to be worthless. In the course of his remarks, he incidentally noticed the method of obtaining the circular motion by means of a crank, which, said he, “occurs naturally in theory, but in practice would be impossible."

This paper was, by the council of the Society, referred to Mr. Smeaton, one of the most distinguished engineers of that age. He not only condemned the crank, but the fly-wheel also; and, in consequence of these views, very complicated and expensive means were adopted, to produce the desired rotary motion from the reciprocating motion of the piston, until, at length, from necessity, the crank and fly-wheel were adopted, and ever afterwards used.

We have mentioned these circumstances to show the wisdom of the course pursued by Captain Ericsson, in not subjecting his invention to public examination, until he could present it in a shape so conclusive, as to satisfy the judgment of practical men; and to trample down that carping, sneering criticism, with which envy and rivalry sometimes seek to strangle the productions of inspired genius. This, in our opinion, he has accomplished. We have, with great care, examined this machine; the principles and coustruction of which were fully explained to us by the distinguished inventor. It is alike remarkable for sublimity of conception and simplicity of detail. Like the forces of nature, its operations, although mighty, are gentle. Two machines upon this plan are now in operation at the works of Messrs. Hogg & Delamater-one of five horse, the other of sixty horse power.

The latter is the most extraordinary piece of machinery we have ever

seen. It has four cylinders. Two, of seventy-two inches in diameter, stand side by side. Over each of these is placed one much smaller. Within these are pistons, exactly fitting their respective cylinders, and so connected that those within the lower and upper cylinders move together. Under the bottom of each of the lower cylinders a fire is applied. No other furnaces are employed. Neither boilers nor water are used. The lower is called the working cylinder; the upper the supply cylinder. As the piston in the supply cylinder moves down, valves placed in its top open, and it becomes filled with cold air. As the piston rises within it, these valves close, and the air within, unable to escape as it came, passes through another set of valves, into a receiver, from whence it is to pass into the working cylinder, to force up the working piston within it. As it leaves the receiver to perform this duty, it passes through what is called the regenerator, which we shall soon explain, where it becomes heated to about four hundred and fifty degrees, and upon entering the working cylinder, it is further heated by the fire underneath. We have said the working cylinder is much larger in diameter than the supply cylinder. Let us, for the sake of illustration merely, suppose it to contain double the area. The cold air which entered the upper cylinder will, therefore, but half fill the lower one. In the course of its passage to the latter, however, we have said that it passes through a regenerator, and let us suppose, that as it enters the working cylinder, it has become heated to about four hundred and eighty degrees. At this temperature, atmospheric air expands to double its volume. The same atmospheric air, therefore, which was contained within the supply cylinder, is now capable of filling one of twice its size. With this enlarged capacity, it enters the working cylinder.

We will further suppose the area of the piston within this cylinder to contain a thousand square inches, and the area of the piston in the supply cylinder above, to contain but five hundred. The air presses upon this with a mean force, we will suppose, of about eleven pounds to each square inch; or in other words, with a weight of 5,500 pounds. Upon the surface of the lower piston, the heated air is, however, pressing upwards with a like force upon each of its one thousand square inches; or in other words, with a force of 11,000 pounds. Here, then, is a force which, after overcoming the weight above, leaves a surplus of 5,500 pounds, if we make no allowance for friction. This surplus furnishes the working power of the engine. It will be readily seen that after one stroke of its pistons is made, it will continue to work with this force, so long as sufficient heat is supplied to expand the air in the working cylinder to the extent stated; for so long as the area of the lower piston is greater than that of the upper, and a like pressure is upon every square inch of each, so long will the greater piston push forward the smaller, as a two-pound weight upon one end of a balance will be quite sure to bear down one pound placed upon the other. We need hardly say that after the air in the working cylinder has forced up the piston within it, a valve opens, and as it passes out, the pistons, by force of gravity, descend, and cold air again rushes into, and fills the supply cylinder, as we have before described. In this manner the two cylinders are alternately supplied and discharged, causing the pistons in each to play up and down, substantially as they do in the steam-engine.

We trust our readers will be able, from the brief description we have here attempted, to understand at least the general principles upon which this machine operates. Its cylinders draw their supply from the atmosphere.

The cylinders of the steam-engine are supplied by scalding vapor, drawn from hissing boilers. The caloric engine draws into its iron lungs, the same element which expands those of the most delicate child, and derives its motion and its power from that sustaining source upon which depends the existence of all animate life.

We have endeavored to explain the construction of the caloric engine. Its most striking feature consists in what is called by its inventor, the regenerator. Before describing this, we will present the grand idea upon which it is based. First let it be remembered that the power of the steamengine depends upon the heat employed to produce steam within its boilers. It will be seen that from the very nature of steam the heat required to produce it, amounting to about 1,200°, is entirely lost by condensation the moment it has once exerted its force upon the piston. If, instead of being so lost, all the heat used in creating the steam employed could, at the moment of condensation, be reconveyed to the furnace, there again to aid in producing steam in the boilers, but a very little fuel would be necessary; none, in fact, except just enough to supply the heat lost by radiation. The reason is obvious. Let us suppose the steam has passed from the boiler, has entered the cylinder, has driven the piston forward, and is about to pass into the condenser, there to change its form, and be again converted into water. This steam, yet in the cylinder, and uncondensed, possesses all the heat it contained before passing out of the boiler. It has driven the piston forward, but in that effort it has lost no heat. That source of power it still contains.

Let it be supposed that the heat contained in the steam could, at the moment it is converted into water within the condenser, be saved, and by some device be again used to create steam from water within the boiler, with what exceeding cheapness could the power of the steam-engine be employed. But it is quite impossible thus to re-employ the heat of steam: it cannot thus be saved; and hence every effort to economize in this manner would be unavailing.

The propositions we have here advanced were, it appears, more than twenty-five years since familiar to the scientific mind of Captain Ericsson. He was at that early period deeply impressed with their importance; and regarding heat as the sole source of motive-power, was anxious to discover some element in which it could be so employed that, after giving motion to machinery, it should be returned to act over and over again for the same purpose. But little reflection was necessary to convince him that steam was not this element. It must consist of some permanent gas, and atmospheric air seemed admirably adapted to the purpose. Accordingly it was employed by him.

In a work entitled "A Dictionary of the Arts of Life and Civilization," published in London in 1833, the author, Sir Richard Phillips, mentions an engine which Captain Ericsson then had in operation in that city, as "his application of excited or rarefied air to the performance of those powers of machinery, which hitherto have been made to depend on the intervention of boiling water and its steam." The author further states that he "has, with inexpressible delight, seen the first model machine, of five horse-power, at work. With a handful of fuel applied to the very sensible medium of atmospheric air, and a most ingenious disposition of its differential powers, he beheld a resulting action, in narrow compass, capable of extension to as great forces as ever can be wielded or used by man."

The author adds:-"The principle of this new engine consists in this: