* the

book entitled "A Century of Inventions, means by which he thought he could put his idea

* Mr. Stuart, in his "History of the Steam Engine," has erroneously stated (p. 12,) that the "Century of Inventions" was first printed in 1683; and this error he has not corrected in the second edition of his work. The full title of the Marquis of Worcester's little book is as follows:-"A Century of the Names and Scantlings of such Inventions as at present I can call to mind to have tried and perfected, which (my former Notes being lost,) I have, at the instance of a powerful Friend, endeavoured now, in the Year 1655, to set these down in such a way as may sufficiently instruct me to put any of them in practice.-Artis & Naturæ proles. London: Printed by J. Grismond, in the year 1663." This little book has been often reprinted; and, in 1825, it was edited, with historical and explanatory notes and twenty-four illustrative engravings, by Mr. Partington.

To the kindness of a friend we are indebted for the sight of a copy of the first edition of the "Century of Inventions," to which is appended a description of "a stupendious Water-commanding Engine, boundless for height, or quantity, requiring no external or even additional help or force, to be set or continued in motion, but what intrinsically is afforded from its own operation, nor yet the twentieth part thereof," &c. &c. It is introduced by a preface, and concludes with a Latin elogium and English panegyric, "composed, through duty and gratitude, by an ancient servant of his Lordship, (James Rollock,) who hath, for 40 years, been an eye-witness of his great ingenuity, indefatigable pains, and vast expenses in perfecting, for public service, not only this most stupendious Water-commanding Engine, but likewise several other rare, useful, and never formerly heard of mathematical conclusions, of which he hath owned a Century, and thereunto I refer you; though this alone were enough to eternalise his name to all ages and future times," &c. &c. An address to the King (Charles II.) follows the preface, and is signed, "Your Sacred Majestie's faithfully devoted and passionately affected, useful if cherished, Subject and Servant, WORCESTER." There is also inserted the Act of Parliament for a Water-commanding Engine, with a prohibition to all others to make use of the same for 99 years; one-tenth part of the profits being also directed to be paid into the Exchequer, and a model of the engine to be delivered by the Marquis to the Lord Treasurer, or Lords Commissioners for the Treasury, on or before the 29th September, 1663, to be by him or them put into the Exchequer and kept there.

The panegyric is headed, "A Panegyrick to the Right Honorable

into practice. These means are, in all their essential points, at least in so far as we can understand them, the bomb-shell half full of liquid, and the ascending vertical tube which I have just described.

The bomb-shell, the same tube, are engraved in Edward Lord Marquess of Worcester, upon his stupendious and never sufficiently-commended Water-work." We insert it, because it is an additional argument for the Marquis having made not only a descriptive invention, but an actual engine, producing such effects as he mentions to have been attained.

The Latin elogium is much to the same purpose, and is written, mutatis mutandis, much in the same style; it is entitled, "In admirandam magis quàm imitandam, aut ullis Encomiis satis prædicandam, illustrissimi Domini Marchionis Vigornice Machinam Hydraulicam Elogium;" and precedes the panegyric.-TR.

"les Raisons des Forces Mouvantes,"* a work of Solomon de Caus. There, the idea is clearly, simply, and unpretendingly set forth. Its origin has nothing romantic; it is connected neither with the events of civil war, nor with a famed state prison, nor even with the rising of the lid of a prisoner's pot; but, what is of infinitely greater importance in a question as to priority, it is, by the date of its publication, forty-eight years earlier than the "Century of Inventions," and forty-one years prior to the imprisonment of the Marquis of Worcester.

The dispute, thus made to depend on a comparison of dates, seemed to be of necessity brought to a close. For how, in fact, could it ever be maintained, that the year 1615 was not earlier than the year 1663? But those whose chief aim appears to have been to expunge every French name from this important chapter in the history of science, suddenly changed their ground as soon as "Les Raisons des Forces Mouvantes" had been extricated from the dusty libraries in which it lay buried. They broke without hesitation their

* The title of the first edition of this work is as follows:-"Les Raisons des Forces Mouvantes, auec diuerses Machines tant utilles que plaisantes, Aus quelles sont adioints plusieurs desseings de grotes et fontaines, par Salomon de Caus, Ingenieur et Architecte de son Altesse Palatine Electorale. A Francfort, en la boutique de Jan Norton, 1615."-TR.

+ M. Arago seems here to imply too sweeping a censure on the English writers on the steam-engine. Although the work of Solomon de Caus, spoken of in the text, appears not to have been known to Professor Robison; yet full justice has been done to his claims by Stuart and Farey at least, if not by other English authors.-TR.

former idol; the Marquis of Worcester was sacrificed to the desire of demolishing the claims of Solomon de Caus; the bomb placed on live coals, and its ascending tube, then ceased to be the true germ of the present steam-engine.

For my own part, I could never bring myself to allow that that man had done no good service, who, meditating on the enormous expansive power of water heated to a high temperature, was the first to see that it might be made available for raising great bodies of that fluid to any conceivable height. I cannot admit that no grateful remembrances are due to that engineer who was also the first to describe a machine fitted to realize such effects. Let us not forget, that we can judge fairly of the merits of an invention only by imagining ourselves carried back to the time when it was first made, and by putting out of our thoughts, for the time, all the information which has been added during the ages posterior to the date of that invention. Let us figure to ourselves one of the ancient mechanicians, Archimedes, for example, consulted as to the means of raising to a great height the water contained in a vast close metal receiver. He would, certainly, speak of huge levers,-of simple and block pullies,-of cranes,-perhaps of his ingenious screw; but how great would be his surprise, if any one were to solve the problem by the aid merely of a faggot and match! I ask, then, can any one dare to refuse the title of an invention, to a process at which the immortal author of the first and true principles of statics and hydro

statics would have been amazed?

The apparatus

of Solomon de Caus, that metal shell in which a moving power almost indefinitely great is generated by means of a faggot and match, will always make a noble figure in the annals of the Steam-Engine.*

It is very doubtful if Solomon de Caus and the Marquis of Worcester ever executed their apparatus. This honour is due to an Englishman,

* It has been asserted in a printed work, that J. B. Porta had given, in 1606, in his “Spiritali," nine or ten years before the publication of the work of Solomon de Caus, the description of an engine intended to raise water by means of the elasticity of steam. I have shewn elsewhere that the Neapolitan philosopher spoke neither directly nor indirectly of any engine in the passage referred to; that he aimed only at determining experimentally the relative volumes of water and steam; that in the little philosophical apparatus employed for that purpose, the steam could not raise the liquid, to use the author's own words, more than a small number of centimètres, or a few inches; that throughout the whole description of the experiment there is not a single word which implies that Porta was aware of the power of this agent, and the possibility of applying it to the construction of a practical working engine.

It may be thought that I ought to have mentioned Porta, were it only because of his researches as to the conversion of water into steam; but I would, in that case, beg to observe, that the phenomenon had already been attentively studied by Professor Besson of Orleans, towards the middle of the sixteenth century; and that in one in particular of the treatises of that mechanician, published in 1569, there is an attempt to determine the relative bulk of water and steam.-M. ARAGO.

The work of Porta to which M. Arago alludes, was first published at Naples in 1601, under the title of "Pneumaticorum libri tres; cum duobus libris curvilineorum elementorum." 4to. It was translated into Italian, and published, also at Naples, with the title, “I tre libri de' Spiritali," 1606, 4to.-TR.

We are not aware that it has ever been maintained that De Caus executed his apparatus. But Mr. Stuart, in his "Anecdotes of Steam-Engines," infers from a prayer of the Marquis which he quotes, and from some correspondence of the Marchioness, that the