Autobiography of Sir John Rennie, F.R.S., Past President of the Institute of Civil Engineers / Comprising the history of his professional life, together with reminiscences dating from the commencement of the century to the present time.

by Sir John Rennie

I therefore made little further progress in anything but classics, in which I became a tolerable proficient, and had Homer, Thucydides, Euripides, Sophocles, Virgil, Horace, &c., at my fingers’ ends, whilst I could scarcely demonstrate the Pons asinorum of Euclid; in fact, in those days a knowledge of Greek and Latin was considered as including everything else, and anything like a science or physics was considered of secondary consequence. I made the acquaintance of two men, who afterwards much distinguished themselves by their scientific acquirements, namely, the late Herbert Mayo, the well-known surgeon and physiologist; also the late Sir George Everest, the scientific Director of the Triangular Survey of India; and Dr. Milman, late Dean of St. Paul’s. Dr. Burney’s school was by no means so well managed as that of Dr. Greenlaw in everything which regarded the comfort of the boys, neither were they so well fed or looked after, and it was a great relief to me when I left the school in 1809.

It then became a question with my father whether I should go to Oxford or Cambridge, or whether I should finish my education at home, under the superintendence of proper masters. About this period, and ever since the year 1802, there was nothing but war heard or talked of all over the world. The whole country was as it were turned into a camp; every man capable of bearing arms became a volunteer, and at school even we were regularly drilled to the use of arms; and I was so excited by the extraordinary victories of Nelson and the early career of Wellington that I determined to enter the army, but to this my father was decidedly opposed, as he wished to bring me up to his own profession. I was therefore reluctantly obliged to give up all idea of the military profession and follow that of a civil engineer; and my father wisely determined that I should go through all the gradations, both practical and theoretical, which could not be done if I went to the University, as the practical part, which he considered most important, must be abandoned; for, he said, after a young man has been three or four years at the University of Oxford or Cambridge, he cannot, without much difficulty, turn himself to the practical part of civil engineering. All idea, therefore, of my going to Cambridge or Oxford was given up. My father at that period had one department of his business exclusively devoted to practical mechanics, that is, to the making of machinery of all kinds; this department, although it formed by no means the principal part of his profession, nevertheless enabled him to make experiments which were of great value in the other departments of his business, and was by no means unprofitable, as the importance of machinery and mechanical contrivances was then to a certain extent appreciated, and was daily becoming more so. My father always said that theoretical and practical mechanics were the true foundations of all civil engineering; and he therefore insisted that as I had to a certain extent learned the theoretical, so I must now learn the practical part. I was therefore sent into the mechanical department, and commenced work planing and sawing boards, making patterns, and other similar works. After this I was put to turning both wood and metal; and although I did not attain complete practical efficiency in these departments, which would have required several years, nevertheless I learned sufficient to enable me to become a tolerable judge of workmanship.

I was then put into the drawing office, where I learned to copy geometrical plans, by which, in a short time, in combination with what I had acquired in the workshop, I gained a general knowledge of design and construction.

My time was employed in this manner about eight hours daily, but my evenings were devoted to the acquisition of geometry, algebra, and trigonometry, plane and spherical; also astronomy under the late Astronomer Royal, Mr. Pond, and his father-in-law, Dr. Bradley, and in learning French, Italian, and German. Having acquired to a certain extent a proficiency in the mathematical sciences, I was placed under the direction of the late Mr. Francis Giles, a land surveyor of considerable experience and ability, who was generally employed by my father to make his various hydraulic surveys for canals and harbours under his immediate direction, which Mr. Giles executed with his usual fidelity and ability. Under Mr. Giles I learned the use of the chain, level, and theodolite, and was enabled to apply my theoretical knowledge in trigonometry, plane and spherical, to practice. About this period, viz. the year 1813, having obtained a tolerable knowledge of the rudiments of my profession, both theoretical and practical, my father determined to place upon my shoulders a certain degree of responsibility, and put me under the direction of that late worthy and excellent man, Mr. James Hollingsworth, whom my father had appointed to be resident engineer of the Waterloo Bridge, which was then building. I felt the responsibility of this office a good deal, and entered upon it with every determination and desire to meet my father’s approbation; and during the inclement winter of 1813-14, when the frost lasted about two months, and the Thames above London Bridge was frozen over for several weeks, I was obliged to attend the piling of the foundations of the first and second piers on the Surrey side of the river night and day for three days each week, which severely tried my constitution.

At this period Vauxhall Bridge was also in course of construction, and I was directed by my father to attend to this also, under Mr. Jones, the resident engineer; but they had scarcely finished the Middlesex abutment up to the springing of the first arch, and were preparing the caisson for founding the first pier, when the Company found that they had not sufficient funds to carry into effect Mr. Rennie’s design, which was very beautiful. The bridge was to be made entirely of the fine blue sandstone from Dundee, and was to consist of seven arches, segments of circles, the centre arch being 110 feet span, with a rise or versed sine of 19 feet, and depth of keystone 4 feet 6 inches; piers 18 feet 6 inches thick at the springing of the arch, the two arches next the centre being 105 feet span each, with a rise or versed sine of 17 feet, keystone 4 feet 5 inches, and springing stones 9 feet long, and the two piers 17 feet 6 inches thick each. The two next arches were 100 feet span, with a rise or versed sine of 15 feet, keystones 4 feet 4 inches, and springers 9 feet, and piers 17 feet thick each; the two sub or shore arches 90 feet span each, with a rise or versed sine of 13 feet, keystones 4 feet, and springers 8 feet, abutments 21 feet thick at the springing, having a total width of waterway of 700 feet. The arches were surmounted by a Roman Doric cornice and plain block and plinth parapet, and the projecting points of the piers were surmounted by solid square pilasters, with a niche in the centre. The roadway was 34 feet wide between the parapets, and was formed by a very flat segment of a circle rising 1 in 53. The piers were intended to be founded by caissons resting upon a platform supported by bearing and surrounded by sheeting piles. This was upon the whole a very elegant, light, and chaste design. Finding that the Company had not sufficient funds to carry into effect the stone design, Mr. Rennie proposed another wholly of iron, consisting of eleven arches, with a total waterway of 732 feet, supported upon cast-iron columns filled with masonry and resting upon a platform supported upon piles and surrounded by sheeting piles. The centre arch was to be 86 feet span and 8 feet rise, and the others diminishing regularly to each end so as to enable the roadway to be formed into a graceful curve rising 1 foot in 60. This also was an extremely light, elegant, and economical design. The total cost of this elegant design was estimated at 100,000l., and would have been executed first, but at that time even this amount was not forthcoming. The works then stopped, and some time elapsed before the Company was resumed, and ultimately constructed the present bridge.

In the year 1814-15 my father was appointed engineer-in-chief of the Southwark Bridge Company, and as this was proposed to be constructed in the narrowest part of the river between Blackfriars and the Old London Bridge, considerable opposition was made to the Act of Parliament for its construction by the Corporation of London and the Conservators of the river, on account of the obstruction which they said the bridge would offer to the navigation; this however was finally overcome, but it was decided by Parliament that the bridge should be constructed with as large arches as possible. Accordingly Mr. Rennie submitted a design consisting of three cast-iron arches, the centre being 240 feet span, with a versed sine of 24 feet, and two side arches of 210 feet each, with a versed sine or rise of 18 feet 10 inches each, with piers of 24 feet wide each at the springing, thus giving a clear lineal waterway of 660 feet, which was a great deal more than that of the Old London Bridge at that time existing. This design was approved of and ordered to be carried into effect. By this time, with the experience of the Waterloo and Vauxhall bridges and my other studies, I had gained considerable knowledge in bridge building, and my father was anxious to give me as much encouragement as possible; although, therefore, he appointed a worthy and practical man, Mr. Meston, as nominally the resident engineer, yet he confided to me the arduous task of making out the working drawings under his own direction, and of carrying them into effect. I therefore felt highly gratified with this great mark of confidence, and devoted my whole energies to the work night and day. The ironwork was carried into effect by Messrs. Walker, of Rotherham, under the able management of their experienced and able superintendent, Mr. Yeats, and the masonry and piling under the well-known contractors, Messrs. Jolliffe and Banks; and Mr. Meston, the resident engineer, faithfully discharged his duties.

As these arches were the largest of the kind ever constructed, considerable doubts as to their stability occurred to many, and the subject was discussed amongst scientific men with considerable energy; and amongst others, the celebrated Dr. Young undertook to investigate Mr. Rennie’s calculations, and came to the conclusion that the bridge was well designed, and would be a perfectly safe and stable structure, and equal to the support of any weight or amount of traffic which could be brought over it. But in order to fulfil these conditions, it was absolutely necessary that every detail of materials and workmanship should be worked out with the greatest skill and accuracy.

As the arches were of such great span with so small rise, the pressure upon the piers and abutments was chiefly lateral; it therefore became necessary to construct them in such a manner that they should offer the most effectual resistance to this pressure. In consequence, the foundations of the abutments were made on an incline, and the masonry from thence upwards to the springing of the arches was made to consist of a series of courses radiating upwards until they reached the angle of the springing courses; so that, in point of fact, the abutments formed, as it were, a continuation of the side arches to their base; and in order to connect the courses of masonry more solidly together, the courses were connected with each other from the top to the bottom by several series of vertical bond stones, thus forming one solid immovable mass. These abutments were supported on a platform composed of piles, double sleepers, and planking, the piles being 20 feet long, 12 inches in diameter in the middle, and driven solidly into the ground at right angles to the inclination of the foundation. As the pressure upon the piers was nearly equal on both sides, it was necessary that the foundations should be laid level. These also rest upon a wooden platform of double sills and planking, lying upon piles of the same dimensions as those of the abutments, driven vertically into the ground below, and the courses of masonry, which were laid horizontally, were connected together in the vertical direction by a series of bond stones in a similar manner to those of the abutments. The abutments and piers were founded many feet below low-water mark of spring tides, so as to be below the reach of any possible scour of the river. Those parts of the piers from immediately below the springing of the arches to a point above the top of the main solid ribs of the arches were composed of large blocks of stone set nearly vertically, breaking bond laterally and vertically with each other, and in the centre of this part of the piers there was a set of keystones 12 feet long and 2 feet thick, tapering on each side, forming so many stone wedges. These were very finely worked on all sides. These wedge stones broke bond laterally with the blocks in front of them, and were firmly driven into their places for a depth of 2 feet by means of heavy wooden rams. The masonry of the pilasters and salient angles of the piers is of the same character as those of the interior of the pier before described, and worked into them in the same manner, so as to form one solid bond from one point of the pier to the other. The whole of the exterior of this part of the piers, as well as of the abutments, is cased with granite from Scotland or Cornwall; and it was necessary that the blocks forming this casing should be of the largest kind, which hitherto was quite unusual, particularly for the facing of the abutments from whence the arches were to spring, which required blocks from 15 to 20 tons. These were of such unusual magnitude, and nothing of the kind had hitherto been used in London, or even elsewhere in England, that the contractors made considerable objection to obtaining them, and even went so far as to say that it could not be done. I was perfectly convinced that it could be done, and that it was merely a question of a little extra expense, and strongly recommended my father to insist upon it, as it was absolutely necessary for the security of the bridge; and he did so, and directed me to proceed to Aberdeen for the purpose of obtaining them. I accordingly started for Aberdeen; and when there, carefully examined all the quarries in the neighbourhood, which I found had only been opened up on a small scale, and were merely adapted for getting paving stones, the commerce of which with London was then upon a considerable scale; but the idea of obtaining blocks of the size required for the Southwark Bridge was considered to be entirely out of the question; or, even if they could be obtained, the price would be such that the contractors would not consent to pay. In fact, so many difficulties and objections were made that I found nothing could be done in that quarter. I therefore determined to proceed to Peterhead, 30 miles farther northward, where the red granite abounds in large masses near the coast, and where I was told that I should probably succeed; but still, they said, even there it would be very difficult to get them. Upon arriving at Peterhead I immediately set to work exploring the adjacent country for several miles round, and soon found that blocks of the size required could readily be obtained, and even larger ones if necessary. I accordingly selected, by way of experiment, a mass of solid rock about four miles to the south of Peterhead, lying within a quarter of a mile of the sea coast, and about 200 feet above the main turnpike road to Peterhead, which ran along the sea shore. This block, weighing about 25 tons, was accordingly marked out, and was soon detached from the main mass of rock by means of wedges, and was 10 feet long and 5 feet square. The workmen who executed this task were rewarded with ample wages and a good supply of whisky, and were extremely proud of their achievement. Then came the important question, how they were to convey it to Peterhead. To get it to the turnpike road was soon accomplished by means of a wooden inclined tramway formed of stout planks moved upon wooden rollers. Good wages and whisky settled this, and the workmen considered it a further great triumph; but still the greater difficulty remained, how to get this vast block (as it was then considered) four miles to Peterhead. I then went back to Peterhead, and after numerous inquiries, and as many failures and objections on all sides, at last found two large single bogies, each consisting of a pair of strong wheels 8 feet in diameter, connected by a strong axle shaft and a double pair of shafts in front. These two pairs of wheels I joined together at the axle shafts by two strong beams, cased with wrought iron, and strengthened the wheels and axles in other respects as far as necessary. I then took this carriage to the block of red granite already mentioned lying in the road, and slung the stone, by means of strong chains, to the two longitudinal bearers of the carriage. Some twelve or fourteen horses were then attached to the carriage, and off we departed in great triumph for Peterhead. The toll-keeper, never having seen such a mass of stone before, did not know what to charge. However, having at length satisfied his demand, we proceeded onwards, and we had scarcely advanced a mile when we came to a soft piece of road, which yielded under the great weight of the stone, and the wheels stuck fast, buried about 9 inches in the ground. This accident created general dismay amongst the attendant workmen, and they began to consider the task hopeless. However, nothing daunted by this mischance, I soon rallied their courage, and with plenty of screw-jacks, wedges, and levers judiciously applied, we raised the wheels out of the ground, and placed strong wooden beams under them, forming a rough kind of railway, over which we dragged and pushed the carriage with its stone in safety, until we had passed the unsound part of the road. This operation detained us about a day. Everybody worked with the greatest ardour and goodwill, which was aided not a little by a plentiful supply of ale and whisky, and the men were determined, for the honour of Scotland, that they would not be beaten. Having overcome this serious obstacle, we started again on our journey, and reached Peterhead about four hours afterwards, making the total length of the journey—four miles—a day and a half. The whole town of Peterhead, having never seen such a sight before, and having considered our task impracticable, turned out to see us, and welcomed us with the most enthusiastic acclamations.

The next thing to be done, having succeeded so far, was to get a vessel that would take this monstrous block of stone, as it was termed, to London; and although there were a considerable number of vessels in the harbour, I could not at first prevail upon any of the captains to take the charge. All sorts of objections were made, and amongst the rest, it was impossible to get the stone on board, and if they did, it would make a hole in the bottom, and the vessel would founder with all on board. At last, after a great deal of difficulty, I found a brig of about 200 tons burthen, the captain of which, after a good deal of persuasion, consented to take the block of stone to London, provided that I would put it on board at my own risk and expense, and indemnify him against all risk or loss on the voyage, which I accordingly agreed to do.

Then came the last important question, how was the block to be got on board? There was no crane in the port capable of lifting above 2 or 3 tons.