AMONTONS-DALESME-SMEATON.

121

degree; while, each time that the steam was condensed in order that the piston might fall, and a stroke be made, the cylinder was cooled down in proportion, and fresh heat, or in other words, more fuel, was wasted in recovering the steam-heat proper for the next rise of the piston.

The names of Amontons and Dalesme, which have sometimes been included in the history of the steam-engine at the epoch of Savery and Papin, we need scarcely do more than barely mention. The “Fire-wheel" of the former, of date 1699, of which an elaborate description, with engravings, is given in the 'Mémoires de l'Académie des Sciences' for that year, and also in Leupold's Theatrum Machinarum,' 1724, (Tab. 53, fig. 2,) consists of a complicated apparatus, depending for its action more on the expansion of heated air than on steam. And of M. Dalesme's project, which bears the date of 1705, the only record that remains appears to be the following, contained in the 'Hist. de l'Académie des Sciences' for that year, and quoted by Prony, (Arch. Hyd.,' ii. p. 90.) "M. Dalesme laid before the Society some ideas which it was thought might prove useful, and be de- . serving of the outlay requisite for experiments on a large scale. His notion is, that the force of the steam which rises from boiling water might be employed as a moving power: he has shown by a machine in which that force alone made water spout to a great height, how powerful it is." The effect described might evidently have been produced by something not more deserving the name of a machine than the hollow ball and tube of De Caus.

The improvements of Smeaton on Newcomen's, or the atmospheric engine, (as it was called from the pressure of the atmosphere on the piston being the moving power in the downward stroke,) are the last to which we are here called on to allude before entering on the consideration of those of Watt. In getting engines erected, Smeaton was so much baffled and annoyed by the irregularity and insufficiency of their work, arising often from the bad proportions of their parts, that he constructed a small experimental engine, not above four horses' power, from which he

deduced a valuable table of the proportions of the parts and of their relative performance; the experiments are said to have been made about the year 1765, although Smeaton did not proceed to build large engines in accordance with the results obtained, till nine years afterwards; soon after which he designed several, some of them of more than a hundred horse power, and in which it was admitted that there was a considerable saving of fuel,-equal in some cases to one-third of the previous consumption. But those were not in existence at the period of Watt's life to which we must now attend; and even the table we have spoken of was not published by its author, but was found after his death among his papers, now in the possession of the Royal Society.

CHAPTER XIII.

DR. ROEBUCK-HIS HISTORY-CARRON IRON-WORKS-BORROWSTONESS-INTRODUCTION TO MR. WATT-PROGRESS OF THE NEW STEAM-ENGINE-TESTUDO BOILER-DIFFICULTIES WITH CYLINDER AND PISTON-PLATE-CONDENSER-CIRCULAR STEAM-ENGINE OR STEAM-WHEEL-DR. ROEBUCK'S EMBARRASSMENTS-MR. WATT'S LANDSURVEYING AND CIVIL ENGINEERING HIS VISIT TO SOHO-INTRODUCTION to dr. SMALL-RENEWED EXPERIMENTS-PROPOSALS OF PARTNERSHIP WITH MR. BOULTON-PATENT of 1769.

FROM the narratives of both Dr. Black and Dr. Robison, it is apparent that, next to the inventor himself, the person at first most deeply interested in the mechanical and commercial success of the invention, the origin of which has now been so fully detailed, was Dr. Roebuck; an ingenious and enterprising man, whose ultimate want of success in life ill rewarded his fondness for practical science, and his energetic exercise of very considerable talents and industry. It seems indeed a singular fatality, that even his early connection with the greatest invention of his age, full of future profit as it promised to be, and narrowly as we now see that it failed to realise that hope to him, was not only of no ultimate service to his own fortunes, but had nearly cut short the progress of the invention itself; which was long submerged, and well-nigh altogether lost, in the financial wreck in which his affairs became involved.

For the best account of the life and pursuits of the gentleman who was thus destined to become the temporary though unsuccessful associate of Mr. Watt in his important scheme, the public are indebted to the pen of the late Professor Jardine, of Glasgow College. From a biographical notice which he communicated to

the Royal Society of Edinburgh, and which is published in their Transactions,* we find that Dr. Roebuck, who was born at Sheffield in 1718, and received some of his early education under the care of Doddridge and in companionship with Akenside, studied medicine at the University of Edinburgh, and formed there an intimate acquaintance with Hume, Robertson, and others of their eminent contemporaries. Graduating at Leyden, on his return to England he settled as a practising physician at Birmingham, where he rapidly rose into extensive and lucrative employment, and was at the same time enabled to gratify his inquiring habit of mind by numerous scientific researches, in which he engaged with ardour. The study of chemistry, one of his favourite pursuits, he now prosecuted practically, with great ingenuity and perseverance; inventing improved and economical processes for refining and working gold and silver, as well as for manufacturing many other substances commonly used in the arts; and, in conjunction with Mr. Samuel Garbett, establishing a large laboratory, where his various processes were profitably carried out on a very extensive scale. Sulphuric acid, which had previously been made, at great expense, in glass retorts, they succeeded, after many experiments, in preparing, by means of leaden vessels, at less than a fourth of its former cost; and on their establishing a manufactory of it at Preston Pans, in East Lothian, the consumption of the article increased enormously, and the profits of their undertaking became proportionally large.

Emboldened by this success, Dr. Roebuck proceeded to carry out a work of far greater extent and importance, which, both in a private and in a national point of view, has more than equalled the sanguine expectations then formed of its probable utility. Among the numerous objects to which he had turned his attention, was the smelting of iron-ore; a process which, as then commonly conducted, was capable, he had satisfied himself, of very great improvement. Having, with his partner Mr. Garbett, now

Trans. R. S. E., iv. p. 65, 1796.

realised some fortune by the profits on his other processes, and being easily enabled, by the confidence reposed in his skill and judgment, to obtain the loan of the further capital that was necessary, he resolved to establish in Scotland a manufactory of iron on a great scale. To him was left not only the direction of all that concerned the buildings, machinery, and processes of the manufacture, but, in the first place, the selection of a proper site for the intended works; and on the banks of the river Carron, in Stirlingshire, he found united every natural facility for his purpose. In that situation, with great water-power, were combined the advantages of ready transport by sea, and supplies, in the immediate neighbourhood, of excellent iron-ore, limestone, and coal,―minerals which, after the lapse of a century, have in that district shown no signs of exhaustion.

The Carron iron-works, in their original state, were completed by the end of 1759, and the first furnace was blown on the 1st of January, 1760.

In planning the Carron machinery, Dr. Roebuck availed himself of the great talents of Mr. Smeaton, who has been justly termed the father of civil-engineering in Great Britain, and who, having in 1750 begun business in London as a philosophical-instrument-maker, was already fast rising to eminence in both of those professions. He had not, however, been previously brought into notice in Scotland; and the introduction of his skill into that country, in which he afterwards directed many important engineering operations, is one of the numerous proofs that Dr. Roebuck gave of possessing an observant and penetrating judgment. Among Mr. Smeaton's Reports, which were published by the Society of Civil Engineers,* and form an interesting memorial of his labours, are included several that were addressed to the Carron Company, concerning the supply and regulation of the water-power, the construction of blowing-machines on improved

* In three volumes, quarto, 1812; which were followed, in 1814, by a fourth volume of his Miscellaneous Papers, comprising all of his communications to the Royal Society, printed in the Philosophical Transactions.