RENNIE, John, a distinguished mechanist, architect, and civil engineer, was born on the 7th of June 1761, at Phantassie, in the parish of Prestonkirk, in the county of East Lothian. His father, a highly respectable farmer, died in 1766, leaving a widow and nine children, of whom John was the youngest. The first rudiments of his education w ere acquired at the village school; and as it frequently happens that some trifling circumstance in early life gives a bent to the pursuits and fixes the destinies of the future man, so it fared with young Rennie. The school was situated on the opposite side of a brook, over which it was necessary to pass by means of a rustic bridge of stepping stones; but when the freshes were out, the only alternative of crossing the stream was by means of a boat, which was kept at the workshop of Mr Andrew Meikle, an ingenious mechanic, well known in Scotland as the inventor of the thrashing-machine, and many improvements in agricultural implements. In passing through this workshop, which stood on his family property, young Rennie’s attention was forcibly draw n to the various operations that were in progress, and a great part of his leisure and holiday time was passed therein. The sons of Mr Meikle, and the workmen, seeing the delight which he appeared to take in examining their labours, were in the habit of indulging him with their tools, and showing him their various uses. His evenings were chiefly employed in imitating those models which had particularly attracted his attention in the workshop; and it is known in the family, that, at little more than ten years of age, he had constructed the model of a windmill, a pile-engine, and a steam-engine. That of the pile-engine is still in existence, and is said to be remarkably well made.

Having continued at Preston school till twelve years of age, he had about that time a quarrel with his schoolmaster, whom he deemed incompetent to give him further instruction, and therefore entreated that he might be permitted to leave the school. But his active mind soon became restless; for the first time he felt the hours hang heavily on his hands; and having expressed a wish to be placed under his friend Mr Meikle, he employed himself with this ingenious mechanic for about two years; but his mind expanding with his growth, he began to feel that the progress of his intellectual faculties was likely to be retarded by a constant application to manual labour. He therefore at length determined to place himself under the tuition [7:19:121]of Mr Gibson, an able teacher of mathematics at Dunbar; where he soon distinguished himself in so particular a manner, that Mr David Loch, general inspector of the fisheries in Scotland, in describing a visit which he paid to the school at Dunbar in 1778, notices the great proficiency displayed by young Rennie; prophesying that at no distant period he would prove an honour to his country. ^[1. Loch'a Essays on the Trade, Commerce, Manufactures, and Fisheries of Scotland, vol. iii. p∙ 211. Q ] From this school, in less than two years, he returned to Mr Meikle, with a mind well stored with every branch of mathematical and physical science which Mr Gibson could teach him. About this time, Mr Gibson being appointed master to the public academy of Perth, he earnestly recommended young Rennie to succeed him at Dunbar. But his views were of a more aspiring cast As a matter of favour, he undertook the management of the school for about six weeks, when he returned to his family, occasionally visiting and assisting his friend Mr Meiklebut mostly improving himself in drawing and making models of machinery. His first essay in practical mechanics was the repairing of a corn-mill in his native village; and he erected two or three others before he was eighteen years of age.

Resolved, however, that these mechanical occupations should not interfere with his studies, he laid his plans so that he should be able to proceed occasionally to Edinburgh with a view of improving himself in physical science. He there attended the lectures of Professors Robison and Black, and formed that acquaintance with the former of these gentlemen, which was gradually raised into friendship, and which, perhaps, may be said to have laid the foundation of his future fortune; for by him he was introduced to Messrs Bolton and Watt of Soho, near Birmingham. With these gentlemen he remained but a few months, for the purpose of receiving explanations respecting the plan of the Albion Mills, then erecting, the machinery of which he superintended. This exactly suited his views; for, conscious of his own powers, he deemed the capital the proper theatre to try their strength, and in this he was not mistaken.

In proceeding from Edinburgh to Soho, he had taken the route by Carlisle, Lancaster, Liverpool, and Manchester, for the purpose of visiting the different mills and public works in those great commercial and manufacturing towns; and the remarks which he made on the bridge then building over the Lune at Lancaster, on the docks at Liverpool, and more particularly on the Bridgewater Canal, are distinguished by great sagacity, and were of essential use to him afterwards. On leaving Soho, he again made a tour through the manufacturing districts of Leeds, Sheffield, Rotherham, and Newcastle.

For some time after he was settled in London, the Albion Mills, of which Bolton and Watt and Mr Wyatt were the projectors and leading proprietors, and who engaged him to superintend the execution of the mill-work, occupied a great share of his attention. Mr Watt, in his Notes to Professor Robison’s Account of the Steam-Engine, says, that, “in the construction of the mill-work and machinery, they derived most valuable assistance from that able mechanician and engineer Mr John Rennie, then just entering into business, who assisted in placing them, and under whose direction they were executed.” He also says, that the machinery, which used to be made of wood, was here made of cast iron, in improved forms; and thinks that this was the commencement of that system of mill-work which has proved so beneficial to this country. In fact, Rennie’s mills are the most perfect species of mechanism in that way that exist, distinguished by a precision of movement and a harmony and proportion of parts that now serve as models throughout the empire. His water-mills are so accurately calculated, that every particle of water is effectively employed, and none of it lost, as in the common mode of constructing water-wheels. There is reason to believe that the difficulties which occurred at the Albion Mills with regard to the ebb and flow of the tides, and which required all the ingenuity of that extraordinary genius, Mr Watt, first led Mr Rennie to the study of that branch of civil engineering connected with hydraulics and hydrodynamics, and in which he soon became so celebrated as to have no rival after the death of Smeaton, in whose steps, he always used to say, he was proud to follow.

Our limited space will not permit us to enter upon even an enumeration of all his great works, much less to give any detailed account of them; we must therefore content ourselves by mentioning some of the most important designs and undertakings in his threefold capacity of mechanist, architect, and civil engineer; three branches of art so intimately blended as scarcely to admit of a separation.

First, as a Mechanist Immediately after the completion of the Albion Mills, in 1786 or 1787, Mr Rennie’s reputation was so firmly established in everything connected with mill-work, that he found himself in a very extensive line of business. To him the planters of Jamaica and of the other West India islands applied for their sugar-mills, which he constructed in a manner so superior to the old ones, that he soon obtained almost a monopoly of these expensive works. The powder-mill at Tunbridge, the great flour-mill at Wandsworth, several saw-mills, the machinery for various breweries and distilleries, were mostly of his manufacture; and wherever his machinery was required to be impelled by steam, the incomparable engines of his friends Messrs Bolton and Watt supplied the moving power; but, contrary to what has been stated in some of the public journals, he never had the least concern in directing, contriving, or advising any one part or movement of the steam-engine. He also constructed those beautiful specimens of machinery, the rolling and triturating mills, at the Mint on Tower Hill, to which Bolton and Watt’s engines give motion; and, at the time of his death, he was engaged in the construction of a rolling-mill, and similar machinery, for the intended mint at Calcutta.

As a bold and ingenious piece of mechanism, which may be considered as distinct from positive architecture, there is nothing in Europe that can bear a comparison with the Southwark Bridge. The three immense arches, the centre one of 240, and each side arch of 210 feet span, consist entirely of masses of cast iron, of various forms and dimensions, put together on the same principle as a similar fabric of hewn stone; a method of employing iron which may be considered to form a new epoch in the history of bridge-building. Various sinister predictions were entertained against this light and beautiful bridge, which was to be rent in pieces by the expansive power of the first summer’s heat, or, if it escaped that, by the contraction of the first winter’s cold; but it has stood the test of many winters and summers, and appears not to feel either. Mr Rennie was applied to by the East India Company for the design of a cast-iron bridge to be thrown over the river Goomty at Lucknow, at the desire of the nabob vizier of Oude. It consisted of three arches of cast iron, the centre arch ninety, and each of the other arches eighty feet span. The arches were cast, and a superintending engineer sent out with them; but on their arrival, the nabob, in one of those moments of caprice to which eastern despots, even in their impotency, are so liable, changed his mind, and would not allow it to be put up.

Secondly, as an Architect. Since there are few parts of civil engineering that do not occasionally require the aid of architecture, Rennie, at a very early stage of his pro[7:19:122]gress, was called upon for a display of his skill in this line. Amongst his first undertakings in either line was that of the Lancaster Canal, which presented many difficulties, and, amongst others, that of carrying it by an aqueduct over the Lune, so as not to interrupt the navigation of the river. Being one of the largest fabrics of its kind in Europe, and of a pleasing design, it is an object that arrests the attention of strangers, and is very generally admired. The bridges of Leeds, Musselburgh, Kelso, Newton-Stewart, Boston, New Galloway, and a multitude of others, attest the architectural skill, the solidity, and, we may add, the good taste of Rennie; whilst a thousand smaller ones, with the various locks, wharf-walls, quays, embankments appertaining to canals, rivers, and harbours, in every part of the united kingdom, are so many proofs of his diversified talent, and his skill in adapting the means to the end. The breakwater in Plymouth Sound can scarcely be called an architectural work, but it is constructed on true hydrodynamical principles, and so gigantic in its dimensions, and cyclopean in its structure, as to defy equally the force of the waves and the ravages of time. To Mr Whidby, who zealously superintended the execution of this immortal work, the highest praise is also due; nor was the plan finally determined on without his advice and assistance.

But the architectural work which, above all others, will immortalize the name of Rennie, is the Waterloo Bridge, a structure which, even foreigners admit, has no parallel in Europe (and if not in Europe, certainly not in the whole world) for its magnitude, its beauty, and its solidity. That a fabric so immense, presenting a straight horizontal line, stretching over nine large arches, should not have altered more than a few inches, not five in any one part, from that straight line, is an instance of firmness and solidity utterly unknown, and almost incredible; ^[2. The bridge of Neuilly, which the vanity of the French led them to rank as superior to that of Waterloo, actually sunk 23 inches. ] but all Rennie’s works have been constructed for posterity. He made nothing slight; nor would he engage in any undertaking where, from an ill-judging economy, a sufficiency of funds was not forthcoming to meet his views.

Another work, executed from a design of his, is that of the stone bridge over the Thames, by which the old London Bridge, so long the disgrace of the metropolis, was replaced. His design, which was selected by a committee of the House of Commons, out of at least thirty that were offered, consisted of a granite bridge of five arches, the centre one of 150 feet span, being the largest stone arch in the world which has been constructed in modern times. This great work, an account of which will be found under the head London, cannot but form a remarkable feature in the future history of the capital. For of the five bridges which connect the two banks of the Thames, three have been built from the designs of one man; a fact which must throw a lustre on the name of Rennie, and be regarded with a feeling of pride by the most distant connection of his family.

Thirdly, as a Civil Engineer. The first great attempt in this line of his profession was the survey and execution of the Crinan Canal, a work remarkable for the multitude of practical difficulties that occurred throughout the whole of this bold undertaking; it being necessary in many places to cut down through solid rock, to the depth of sixty feet; and it is rather remarkable, that the second undertaking, the Lancaster Canal, was also replete with difficulties, and called for the exercise of his skill as an architect, as we have already seen in noticing the aqueduct over the Lune. But these two works established his reputation as a civil engineer, and his opinion and assistance were required from all quarters. His faculties were now called into full play, and they expanded with the demands made upon them. The rage for canals had pervaded every part of the kingdom, and scarcely any of these useful means of conveyance and communication was thought of without a previous consultation with Rennie; so that in a few years the surveys he was called upon to make were so numerous, that he knew the surface of England as it were by heart, and could tell at once, when a canal was projected, whereabouts the line of it ought to be carried. The following are some of the most important of those the execution of which he personally attended: Aberdeen, Brechin, Grand Western, Kennet and Avon, Portsmouth, Birmingham, Worcester, besides many others.

But the resources of his mind were displayed in all their vigour in the plans and construction of those magnificent docks, which are at once an ornament to the capital, and of the utmost utility to commerce and navigation. Nor are these splendid and useful works confined to the metropolis. The docks at Hull, Greenock, Leith, Liverpool, and Dublin, attest his skill; and the harbours of Queensferry, Berwick, Howth, Holyhead, Dunleary (now called Kingstown Harbour), Newhaven, and several others, owe their security and convenience to his labours.

But even these works, splendid as they are, must yield to what he has planned and executed in her majesty’s dock-yards at Portsmouth, Plymouth, Chatham, and Sheemess. The latter was a mere quicksand of forty feet in depth, mixed with mud and the wrecks of old ships; the whole of which was excavated, and a magnificent basin constructed, with a beautiful surrounding wall of granite, with which three of the finest dry docks in the universe communicate; and that important dock-yard, which may be said to command the mouths of the Thames and the Medway, from being an unhealthy and detestable place, and wholly inefficient for its purpose, is now, by being raised many feet, and laid out with skill and judgment, one of the most convenient in the kingdom, He also planned the new naval arsenal at Pembroke, which is considered as a perfect model for a building-yard. But his plan for the projected naval arsenal at Northfleet on the Thames was far superior to all in design; and upon a scale so grand as to be capable of containing afloat two thirds of the whole navy, with dry docks and slips for repairing and building ships of all classes to the same extent, and with all manner of storehouses, workshops, and manufactories of all such articles as were required for consumption in the navy. But the estimated sum of eight millions, which would probably have amounted to ten, induced the government to pause, and it was finally deemed prudent to abandon the design altogether.

Mr Smeaton, we believe, was the first who used the diving-bell effectually for building with stone under water; but the machine he employed for that purpose was very defective, and could be used only in certain situations. Rennie, however, by improvements in the instrument itself, and in the machinery by which its movements could be regulated, was enabled to carry on the finest masonry, and the foundations of sea-walls, piers, and quays, as well under water as above it The repairing of the pier-head of Ramsgate Harbour was a remarkable instance of this kind. The violence of the waves, acting upon the bad quality of the stone, had so completely undermined it that the stability of the whole pier began to be endangered. It was from ten to thirteen feet below the level of low water, spring-tides; yet by means of the improved diving-bell and its apparatus, the pier-head was not only effectually secured, but rendered more solid and durable than it originally had been. In the harbour of Howth the diving-bell was of the utmost use; and it is remarkable enough, that the masons who have been for a little while accustomed to work under water prefer it, at least the Irish masons do, to working in the air,
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it being cooler in summer, and warmer m winter; though an increase of pay for submarine work is probably the real cause of preference.

The last effort of Rennie’s genius to which we shall advert, was the drainage of that vast tract of marsh land bordering upon the rivers Trent, Witham, New Welland, and Ouse, which for centuries past had baffled the skill of some of the ablest men in that department of civil engineering. Upon the same principles, he laid down a grand scheme for draining the whole of that immense district known by the name of the Bedford Level, which has in part been carried into execution by the completion of the Eaubrink Cut, near Lynn. The estimate he made for draining the whole amounted to L.l,200,000.

Such are some of the grand undertakings which Rennie, during the last thirty years of his life, was either employed to project or to carry into execution, and which, on a rough estimate, collected from his valuable Reports, did not fall far short of forty millions sterling; about twenty millions of which were expended under his own immediate superintendence. Indeed, few great works were carried on, either by the public or individuals, on which he was not either employed or consulted. His industry was very extraordinary. Fond of the society of his select friends, and of rational conversation, he never suffered amusement of any kind to interfere with his business, which seldom engaged him less than twelve hours, and frequently fifteen, in the day. His conversation was always amusing and instructive. He possessed a rich fund of anecdote, and, like his old friend James Watt, told a Scotch story admirably. As a travelling companion, he was highly entertaining; he knew everybody on the road, and everybody knew John Rennie. Of an ardent and anxious mind, and naturally impetuous, he was gifted with the most perfect self-control; and the irritation of the moment was seen but as a light summer’s cloud, passing across his finely-marked features, which were on so large a scale, though blended with much mildness as well as dignity, as to obtain for his noble bust by Chantrey, when exhibited in Somerset House, the name of Jupiter Tonans.

Were we to seek for a parallel to Rennie, the name of Smeaton would at once suggest itself. Their boyhood was employed precisely in the same manner, in making models of pumps and windmills, whilst their school-fellows were at play; their pursuits in manhood were similar, and their paramount success pretty nearly the same. But the spirit of speculation and improvement was but just springing up when Smeaton finished his career, and when Rennie began his. He was, in fact, the successor of Smeaton. There was a strong characteristic likeness between Rennie and the late Mr Ramsden. The pursuits of the former embraced a wider sphere of action, but they both arrived at their proposed objects by the most simple and obvious, and, at the same time, most effectual means. They were both equally clear in their mode of communicating information to others; and it is sufficiently remarkable that, in their illustrations, both of them had recourse rarely to any other instrument than a two-feet rule, which each always carried in his pocket Many a time has the writer of this article derived instruction from the two-feet rules of John Rennie and Jesse Ramsden. They were both equally communicative when they saw that information was desired; and nothing like professional jealousy, or selfish feelings, actuated either of these ingenious men, who, on the contrary, were always kind and condescending to the more humble artists of their respective professions.

Mr Rennie possessed considerable skill in bibliography; and being a zealous and liberal collector, he succeeded in forming a very valuable library, consisting of the best and rarest books in all the branches of science and art, of voyages and travels, and many curious books in the black letter; whilst in his own department it contained every work of the least merit, in whatever language it might be written. He· had, besides, a good collection of mathematical and astronomical instruments, and frequently spoke of erecting an observatory, but did not live to carry his intention into execution. He had for some years laboured under a disease of the liver, which had apparently yielded to the usual treatment; but a relapse took place, and on the 16th of October 1821, after a few days’ illness, he expired without a struggle, in the sixtieth year of his age.

Mr Rennie, in 1789, married Miss Mackintosh, who died in 1806, leaving a family of seven young children, six of whom are now living. The two eldest, George and John, are successfully following the profession, and promise to tread in the footsteps, of their able and excellent father.

Sixteen mourning coaches, filled with his friends, mostly men of eminence in the arts, sciences, or literature, followed his hearse to St Paul’s, where his remains were interred near those of Sir Christopher Wren. A plain granite slab covers his grave, on which is the following appropriate inscription:

Here lie the mortal remains of JOHN RENNIE,

Civil Engineer,

F. K. S. L. & E. F. A. S. &c. &c.

Born at Phantassie, in East Lothian, 7th June 1761; deceased in London 4th Oct 1821.

THIS STONE

testifies his private virtues, and records the affection and the respect of his family and his friends; but the many splendid and useful works by which, under his superintending genius,

England, Scotland, and Ireland, have been adorned and improved, are the true monuments of his public merit (m.)