sive, irresistible experiments, succeed to conjectures destitute of proof.

In 1605, for instance, we find Flurence Rivault,* a gentleman of the bed-chamber to Henry IV., and the preceptor of Louis XIII., discovering that a thick bomb-shell, containing water, is sure to explode when it is put in the fire after having been plugged;—that is to say, when the steam is prevented from diffusing itself freely through the air in proportion as it is generated. The power of steam is here shown to be capable of a clear proof, which may to a certain extent be numerically estimated; † but it also presents itself to us as a frightful instrument of destruction.

*The title of his book is, "Les Elemens de l'Artillerie, concernans tant la premiere inuention et theorie, que la practique du Canon. Par le Sieur de Flurance Rivavlt. A Paris chez Adrian Beys, rue Sainct Jacques, ioignant la Rosse Blanche. M.DC.v."-TR.

+ If any learned person should object that I have not gone far enough back when I stop at Flurence Rivault; if he should adduce a quotation from Alberti, who wrote in 1411, to inform us that so early as the beginning of the fifteenth century, lime-burners greatly dreaded, for the safety both of their kilns and of themselves, the explosions of limestones within which there happens to be a cavity, I would reply that Alberti himself was ignorant of the real cause of those dreaded explosions; that he attributed them to the action of the flame converting into vapour the air contained in the cavity; and lastly, that a limestone accidentally hollow, would not have furnished any of the means of numerical calculation which the experiment of Rivault appears to admit of.—M. ARAGO.

The passage of Alberti in which these explosions and their cause are mentioned, is as follows:-" Si è trouato che nel mezo delle pietre, & massimo delle tonde, sono alcuna volta certe concauitati, nelle quali rinchiusa l'aria, arreca danni grandissimi: Percio che acceso il fuoco nella fornace, egli auiene mediante, ò il fuoco, ò pure il freddo, che và allo indentro, che essa aria si ristringa, ò pure che riscaldandosi finalmente essa pietra, la medesima aria si conuerta in

Some great minds, not satisfied with this uncomfortable reflection, conceived that mechanical powers, like human passions, must become advantageous, or hurtful, according as they are well or ill directed. In the particular instance of steam, there is, in fact, need only of the most simple artifice to apply to productive labour that formidable elastic power which, to all appearance, shakes the earth to its very foundations, surrounds the art of the metal-founder with real perils, and shatters into a thousand fragments the thickest bomb-shell! In what state is this projectile before it explodes? Its lower part contains water, very hot, but still liquid; the remainder of the space is filled with steam; this latter, with the distinctive property of gaseous substances, presses equally in all directions, acting with the same degree of force on the water as on the metal case which contains it. If, at the lower part of this case, we place a cock, as soon as it is turned, the water, expelled by the steam, will rush out of it with extreme velocity. If the cock terminates in a tube, which, after being bent round the outside of the bomb, is pointed vertically upwards, the discharged water will ascend in it so much the higher as the steam is more elastic; or rather, for it is the same thing in other words, the water will rise the higher in proportion to the increase of its temperature. This ascending movevapore; Et è certo che egli rigonfia, & rompendo per ogni verso la prigione in cui si truoua, con scoppio, & impeto grandissimo sene esce, & disturba & manda sozzopra tutta la massa della fornace." L'Architettura di Leonbatista Alberti, Firenze. M.D.L. P. 56. 1. 37. -TR.

ment will meet with no limit but the strength of the sides of the apparatus.

If for the bomb-shell we substitute a thick metal boiler of a vast capacity, there is nothing to prevent our raising great bodies of liquid to indefinite heights, by the mere action of steam; and we shall thus have created, in every sense of the word, a steam-engine available as a pump.

You have now been made acquainted with the invention for which France and England have contended, as in times of yore seven cities of Greece, in their turn, arrogated to themselves the honour of having been the birth-place of Homer. On the other side of the Channel, all have concurred in attributing the merit of it to the Marquis of Worcester, of the illustrious house of Somerset; on this side of the strait, we maintain that it belongs to a humble engineer, almost altogether overlooked by biographers,* viz. Solomon

* So much so, that it has been questioned whether De Caus was really a native of France. The only guide to any certain knowledge of Solomon de Caus' life that we have been able to find, is the internal evidence of his own writings. From these it appears, that his principal works were published on the English side of the Channel, or, like those of Papin, "beyond the Rhine;" and it is sufficiently singular, that the distinguished patronage which he frequently and gratefully acknowledges, was conferred on him by the Royal Family of that country, which, in all that relates to mechanical science, seems then, as now, to have asserted a proud pre-eminence.

Solomon de Caus was, as he states in the dedication prefixed to the second Book of his "Raisons des Forces Mouvantes," for some time in the service of the Prince of Wales at Richmond. This was Prince Henry, (not Charles, as erroneously stated by Mr. Stuart in his "Anecdotes of Steam Engines," 1829,) son of James I., who died in 1612, and whose sister Elizabeth was married, three months

de Caus, who was born at Dieppe or in its neighbourhood. Let us take an impartial glance at the respective claims of these two competitors.

afterwards, to the Elector Palatine. Upon this event, De Caus went over to Heidelberg, where he became "Ingenieur et Architecte de son Altesse Palatine Electorale," and from this place most of his books are dated. The dedication above alluded to is, "A la Tresillustre et Vertueuse Princesse Elizabeth, Princesse de la Grande Bretaigne, Electrice Palatine;" and in the preceding year, 1614, he dedicates another work, "Institution Harmonique," " A la Tresillustre et Vertueuse Dame Anne, Royne de la Grande Bretaigne." In the "Beauties of England and Wales," it is stated, that, "Monsieur Solomon de Caus, Inigo Jones, and Webb, were successively engaged to enlarge and embellish" Wilton House, the famous seat of the Herberts, Earls of Pembroke, in Wiltshire. In the catalogue of the British Museum a book is ascribed to Isaac de Caus, called "Wilton Garden." This Isaac published a work of which one edition appeared in 1657, but another is without date, entitled, "Novvelle Invention de lever l'Eav plvs havlt que sa source, auec quelques Machines mouantes par le moyen de l'Eau et vn discours de la conduite d'ycelle, par Isaac de Cavs, Ingenyeur et Architecte, Natif de dieppe." In 1659, a translation of this, by John Leak, was published in London, in which exactly the same copper-plates are employed for illustration as in the original volume.

From their surname being the same, and from the great similarity of many of the mechanical contrivances which they invented or described, as well as from their both having apparently found professional employment in England, there seems reason to conclude that the two De Caus were in some way related to each other; and, if they were not brothers or cousins, but either father and son, or uncle and nephew, Isaac appears, from the smaller number of the mechanical contrivances which he has published, to have been the first in order of time, although this is not so stated in the usual biographical accounts. Mr. Stuart, in his "Anecdotes of Steam-Engines,' seems to consider them to be the same person, under different names, (vol. i. p. 27.)

On the authority of the title-page to his work already cited, Isaac may be held to have been a native of Normandy. It is possible that the same authority may be the only one that has led his biographers to call Solomon also a Norman. M. Arago, in the Annuaire

C

The Marquis, being seriously implicated in the intrigues in the latter years of the reign of the Stuarts, was imprisoned in the Tower of London. One day, as the story goes, the lid of the pot in which his dinner was cooking, suddenly rose. What can a man do in such a case, but think? The Marquis, then, thought about the strange phenomenon he had just witnessed. Then it occurred to him that the same force which had lifted the lid, might become, in certain circumstances, a useful and convenient moving power; after regaining his liberty, he explained, in 1663, in a

du Bureau des Longitudes for 1830, only says that he was a Frenchman, without more minutely particularising the place of his birth. And the only arguments by which he supports even this general assertion are, 1. that he wrote in French, 2. that he calls himself, in a dedication to Louis XIII., a subject of that monarch, and, 3. that he is also styled his subject in the privilege granted to his publication. But these circumstances are consistent with the supposition of his having been French only by extraction, as he might, even in that case, take a pride in using the language of his fathers, and claiming his connection with their country and its sovereign, while in the privilege the designation which he adopts in the dedication is naturally repeated.

It may be worth observing, that Solomon de Caus' books printed at Frankfort were published "En la boutique de Jan Norton, Libraire Anglois;" and his first work, "La Perspective avec la Raison des Ombres et Miroirs," was published in London (1612.) He seems afterwards to have gone to Paris, at least in 1624 he published there, "La Pratiqve et Demonstration des Horloges Solaires," and a second edition of "Les Raisons des Forces Mouvantes."

It must not be supposed, from the above observations, that we intend to assert that Solomon de Caus was born in England; of this we have no proof; but the weight of proof as to his birth-place rests on the nation which has claimed the honour of his inventions, and the circumstances mentioned above seem to shew that on this point there is yet some room for doubt.-TR.