my essay. Dr. Hare, no doubt unintentionally, entirely misstates my views, when he says that I " think it expedient to have it enter near or through the floor." This represents me as writing nonsense--for do I not speak distinctly against letting it pass through a hole or grate in the floor ? and surely this would be "near or through the floor." The principle that I want to establish is, that the flues or pipes by which the heated air passes off from the heatchamber, into the apartment to be warmed, in whatever direction they be carried under and through the floor, should not terminate there, but pass above the floor, and there have a horizontal direction, (or parallel with the floor) to some extent, before they terminate. What specific length this horizontal branch should have, it would require many experiments to establish. My horizontal branches were six inches long, as stated in my essay. When I spoke of giving this horizontal direction to the hot air, whilst it was yet in a constrained passage, I thought that if my language was not sufficiently explicit, that the apparatus which I applied and described, would make it plain enough at any rate, it was intended to convey what I have now in other words described above. The momentum or force which I contend the heated air has, when it issues from the heat-chamber--and which I say so powerfully contributes to carry it to the ceiling, when it passes through a mere opening or openings in the floor, I see Dr. Hare destroys by his arrangement of many small perforations; for, if I understand his language, all his openings, distributed over a surface of thirty feet, are mere openings in the floor, covered with perforated plates, and do not change the vertical current of heated air. Now, for this arrangement of Dr. Hare's I cheerfully concede to him all the credit it deserves, and grant too that he adopted it not by accident, but upon reflection, and upon principles that he perfectly understands. But I beg leave to assure him, that if he thinks that these views are parallel with mine, that he has neither by accident nor reflection fallen on my views. The momentum or force I speak of is a very desirable agent with me-I do not wish to destroy it,-but to apply it to a very useful purpose, and on this I build my claims of discovery. By bringing the heated air into the horizontal branch or branches of flues, this force is expended in carrying the heated air over the apartment, and into every part of it; that it does this, I have sufficiently established. The column of hot air, as it passes from the flue, meeting with the resistance of the atmosphere, produces a spray, analogous to the spray of water from the branch pipe of a fire engine, and is in this way divided into many parts, and commingles thus with the cold airevery small division passing in the desired direction, until the momentum is expended. And as a part of the spray from a fire engine, when the column of water first divides (the branch pipe being held horizontally) passes upwards contrary to its own gravity, so a part of the spray of heated air passes downwards; as may be readily seen in my arrangement. The horizontal pipes are six inches from the floor, and yet small light articles are blown along the floor to its very extremity. Although my horizontal pipes are six inches above the floor, I feel convinced that it is best to have them much nearer, as I stated in my former essay. To cover my horizontal branches or flues with plates, replete with many perforations, would be as unwise as to cover with a similar plate the branch pipe of a fireengine. Respectfully, WM. GRIES, M. D.

Womelsdorf, Pa., Dec. 30th, 1839.

History of the Steam Engine, with a reply to the Criticisms to which the first publication of the article gave rise. BY M. ARAGO.

[Froin the Annual of the Board of Longitude, for 1836.]

TRANSLATED BY LIEUT. A. A. HARWOOD, U. S. N.

The steam engine has already rendered such important services to navigation and the arts, that we cannot be surprised at the eagerness with which researches have been made to ascertain the share which different nations may claim in this admirable invention.

The fact will nevertheless excite some surprise, that in England alone, the booksellers have sold, in a very few years, more than an hundred thousand copies of numerous works, in which this historical question is argued. This brilliant success is, I doubt not, principally due to the lively interest which the steam engine must naturally excite in a country in which it is every where in use; but perhaps, we shall not be far wrong in attributing some portion of it to national pride. Ask, in fact, the members of the House of Lords, and the simple artisan, the city merchant whose brilliant speculations have conducted him to every region of the globe, and the farmer who has never been beyond the limits of his native country; visit the immense manufactories of Birmingham, Manchester, and Glasgow, and the humblest workshop;-everywhere you will be told that the Marquis of Worcester was the first inventor of the steam engine; and after his name, you will find in every body's mouth the names, all English ones, of Savery, Newcomen, Beighton, Watt, Hornblower, Woolf, &c. In general, literary persons, and those especially devoted to the cultivation of science, are not more liberal in their opinions upon this subject. In Dr. Rees' Cyclopedia, we find these remarks: The Steam Engine follows next to the Ship in the scale of inventions; but in an English Cyclopedia it will take the lead, from the circumstance of its being wholly invented and brought into general use by our countrymen, (article Steam Engine, 2d col.) and eleven lines lower down, as if the first passage was not sufficiently explicit,The Steam Engine is the invention of a few individuals, all of them Englishmen.' The celebrated professor John Robison, of Edinburgh, is equally positive. • The Steam Engine, 'says he,' was beyond all doubt first invented by the Marquis of Worcester, in the reign of Charles the Second.' (See a System of Mechanical Philosophy, vol. II, p. 46.) After having afterwards refuted, by arguments which I shall examine, the pretensions of French authors, who affect to blend the name of Papin with the history of the Steam engine, Robison declares, that he does not hesitate at all to give the honour of the first and complete invention to the Marquis of Worcester. (See a System, &c., page 50.) A Savant not less illustrious for depth of knowledge than for vast erudition, Dr. Thomas Young, has added his imposing testimony to those already cited. According to him, the Marquis of Worcester is the first inventor of the Steam Engine, and the first who made use of the pressure of steam as a moving power. In the rapid sketch which he gives of the

6

*No apology is necessary for presenting to our readers an article of permanent interest, like this, which has been twice published in the Annuaire of the Board of Longitude. We hope that some of our Correspondents may be induced, by seeing the article in English, to set the claims of our countrymen, Rumsey, Fitch, Evans, Stevens, and Fulton, in a more just light than is here done. COм. PUB,

improvements which this machine has successively received, English machinists alone are made to figure, (Lectures on Natural Philosophy, vol. 1st, p. 346 a 356,) I might also cite Mr. Millington, the able professor of Mechanics at the Royal Institution, Mr. Lardner, a distinguished member of the New University of London, and Mr. Nicholson, the author of a valuable treatise on practical Mechanics.

Decisions so numerous, so positive, and derived from works of such high reputation did not seem to me, at first, to admit of the shadow of a doubt. When, therefore, at the request of the pupils of the Polytechnic School, I attempted, some years ago, to trace the chronological series of improvements which the steam engine has undergone, from its origin up to the present day, I frankly acknowledge I expected to have none but English mechanicians to quote. This however was an error our neighbours of the other side of the channel are neither the only nor even the first inventors of the Steam Engine. This at least appears to me to be proved by the passages which I now submit to the readers of the Annuaire. I feel sure, at all events, of having examined this curious point in the history of the sciences without prejudice, and that my citations and analyses may be depended upon as exact. If the deductions from them are not so, the reader will be able to rectify them himself, since he will be furnished with all the elements of the question.

I ought, before concluding this preamble, to observe further that there has recently appeared in England a remarkable work, entitled a descriptive History of the Steam Engine, by Mr. Robert Stuart, in which all the attempts which have been made to use steam as a mechanical agent are estimated with a great deal of discernment; and, which is still rarer, with an entire disregard to national prejudice. With few exceptions, the opinions of Mr. Stuart upon the relative merits of the engineers who have contributed to the creation of this wonderful machine, agree perfectly with those which I had formed from the study of the original records. I naturally take advantage of this flattering coincidence with eagerness; I may even add that if my memoir had not been nearly drawn up when Mr. Stuart's history came into my hands, I should probably have been satisfied with the insertion of a simple analysis of his book, by doing which, the end that I proposed to myself would have been equally attained.

I hope the reader will appreciate the motives which have determined me not to follow strictly a chronological order in every part of this article. I have concluded that there would be greater clearness in collecting together the paragraphs relating to the various and more or less advantageous modes which have been successively conceived for the employment of steam. The details of mechanism, though very important, seem to me to be of secondary consideration.

120 years B. C. Hiero of Alexandria.*

When liquids, gases, or vapours, flow from vessels which contain them un*Hiero of Alexandria, lived nearly 120 years before our era. The greater part of the numerous works which he composed are lost; there are only three of them remaining. The reacting machine here in question, is found described, and represented in the treatise, entitled, Spiritalia seu pneumatica. The invention of cogwheels is claimed for Hiero; but this honor belongs, I believe, to his master Ctesibius. His water clocks, and above all, his automata, excited the admiration of antiquity. The fountain which bears the name of Hiero has been applied to various important purposes, even in our days; it serves for instance, in the mines of Schemnitz, in Hungary, as a draining machine.

der certain conditions which I shall describe, they become a cause of motion which it is necessary to estimate properly in order to understand the operation of a little apparatus contrived by Hiero of Alexandria, which offers, I think, the first example of the employment of steam as a motive force. Imagine a bent tube A, B, G, the two branches of which A, B, and B, G, meet each other rectangularly. Let us suppose that the branch B, A, is vertical, that it passes freely through a fixed ring m, n, and that it rests beneath upon a sharp point T, so as to turn upon itself without interruption. If in this situation water is poured in by the upper funnel, we shall have two distinct cases to consid

A

B

T

SG

When the liquid flows through the extremity G, in the direction B, G, the whole apparatus will remain motionless. When, on the contrary, the tube B, G, is stopped at its extremity G, and the liquid escapes only by the lateral opening S, in a horizontal direction, the machine will be put in motion. It will turn round A, B, as long as the flow continues, but in a contrary direction to that in which the jet is formed. If, for instance, the water is forced forward, the horizontal tube B, G, will revolve in a contrary direction by a species of recoil.

All the machines in which water has been thus employed, are called reacting machines.

A gas passing rapidly through the bent tube A, B, G, would produce the same effects as the water: the tube would be at rest while the gas escaped in the direction B, G; on the contrary, it would turn if the escape took place laterally.

These preliminary considerations will suffice to explain the mode of action of steam in the machine of Hiero.

A

D

Let us imagine that a hollow metallic sphere, contrived so as to turn between two pivots A, and B, is filled with a very elastic vapour; that this vapour may escape from the sphere by a projecting tube D, G, perpendicular to A, B, and placed upon the prolongation of one of the radii. We have already seen that if the tube D, G, is open at its extremity, it will not incline to revolve, and that the sphere will remain at rest; and on the contrary, that if the escape takes place by the lateral opening S, in front for instance, the tube will recoil, and will tend to make the sphere to which it is attached revolve with a backward motion. To ensure the continuance of this rotary motion it will suffice to add to the preceding suppositions, that one of the two pivots, (A for instance) is hollow, that it communicates at one end with the inside of the sphere, and at the other with the boiler: the steam expended at S, will in this way be constantly replaced as fast as it escapes.

B

In the figure which Hiero has given of his little apparatus, two tubes are seen like that which I have just described. They form the opposite prolongations of the same diameter, and their lateral openings are so disposed as to make the sphere turn in the same direction.

1*

There is also in the Spiritalia the description of a machine differing from the preceding in this particular only, that a current of heated air takes the place of a current of vapour.

To sum up, we find a certain employment of aqueous vapour in one of the contrivances described by Hiero; but the action of this vapour differs from that of steam in modern machines. Watt, to whom the experiments of the Greek mechanician were not unknown, thought that no use could be made of them. Others, if I am correctly informed, have entertained, on the contrary, a sufficiently favorable opinion of the effects which might be produced by Hiero's mechanism, when perfected, to have sought to secure to themselves the exclusive enjoyment of them by a patent. Time and experience will decide. We see only, that if by modifications of which we now have no idea, steam machines upon a reacting principle shall one day or other succeed, and it is thought necessary to write a history of them, the honour of their first invention must be awarded to Hiero. For my part I might have passed them over altogether in silence, since I have only to do with known machines, such as are in common use, and which have no affinity with the revolving sphere of the Alexandrian philosopher. Perhaps, indeed, it had been proper to cite here in preference, authors, who, like Aristotle, and Seneca, attribute earthquakes to the sudden transformation of water into steam. This change, according to them, takes place in the womb of the earth by subterranean heat, and the prodigious effects which they endeavor to account for, shew clearly the enormous mechanical power they imputed to steam. I hope, at all events, that this article may find excuse when it is seen that it gives a natural solution of the important question to which the paper which I am now going to take up has given rise.

1543. Blasco de Garay.

M. de Navarrete, published in 1826, in the Baron de Zach's Astronomical Correspondence, the following note, which was communicated to him by Mr. Thomas Gonzalez, director of the royal archives of Simuncas.

"Blasco de Garay, a Captain in the Navy, proposed in 1543, to the Emperor and King Charles the Fifth, a machine to propel large boats and ships even in calm weather, without oars or sails.

"In spite of the impediments and the opposition which this project met with, the Emperor ordered a trial to be made of it in the port of Barcelona, which in fact took place on the 17th of the month of June, of the said year,

1543.

"Garay would not explain the particulars of his discovery; it was evident, however, during the experiment, that it consisted in a large copper of boiling water, and in moving wheels attached to either side of the ship.

"The experiment was tried on a ship of 200 tons, called the Trinity, which came from Colibre, to discharge a cargo of corn at Barcelona, of which Peter de Scarza was Captain.

"By order of Charles V, Don Henry de Toledo, the Governor, Don Pedro de Cordova, the Treasurer, Ravago, and the Vice Chancellor, and Intendant of Catalonia, witnessed the experiment.

"In the reports made to the Emperor, and to the Prince, this ingenious invention was generally approved, particularly on account of the promptness and facility with which the ship was made to go about.

"The Treasurer, Ravago, an enemy to the project, said that the vessel could be propelled two leagues in three hours; that the machine was too complicated and expensive, and that there would be an exposure to danger