Autobiography of Sir John Rennie, F.R.S., Past President of the Institute of Civil Engineers. Sir John Rennie
that the port of Venice is now capable of receiving as large, if not larger, vessels than she ever received before; for it should be recollected that in the most flourishing times of Venice there were no ships drawing 23 or 24 feet, and vessels of this size can now enter and depart at all times. Hence Venice has been converted into a port fit for modern requirements; but it must always be borne in mind that so strong are the natural obstacles against its maintenance that nothing can preserve it in its present condition but the most constant vigilance and care. Fortunately the method of dredging by steam has been introduced, and this may be done to any extent, at a comparatively moderate cost, but it can only be compensated for when there is a sufficient amount of trade to pay for it. Still, in whatever way we may consider the question, it must be admitted that the port of Venice has been preserved in a most extraordinary manner during so many centuries, notwithstanding the natural obstacles against it; and now that it has been connected with the kingdom of Italy, there is no further drawback to its full development, and it only requires self-reliance and energy to render it what it once was, one, if not the most important, of the commercial cities of Italy.
At Bologna we had the pleasure of making the acquaintance of the celebrated linguist Mezzofanti, whose modest and simple manner, accompanied by his extraordinary acquirements, quite enchanted us. The singular fact is that at the time of our meeting him he had never been out of the province of Bologna, and yet he had acquired the knowledge of twenty-four languages, and, as far as our limited acquaintance went, he spoke the English, German, French, Greek and Latin tongues perfectly; and those conversant with the Oriental languages informed us that he spoke them equally well. He appeared to be completely absorbed in languages, and was scarcely acquainted with any other branches of knowledge; still his wonderful mastery of this branch of study was a great acquirement, and must have required vast powers of memory as well as indefatigable study.
From thence we passed through Ravenna to Ancona, the position of which is good, occupying as it does a salient point of the coast. The water is deep and there is a commanding height for a citadel. The Roman emperors resolved to take advantage of the situation, and built a town here, the place being well adapted for a seaport. They accordingly made a mole on the south side to protect the harbour against the most dangerous winds, namely, those blowing from the south; they commenced the work from the shore by throwing down large blocks of rough stone, which were obtained from the rocks in the vicinity, in order to form a base for the superstructure; these blocks of stone were deposited promiscuously in the sea and left to the action of the waves, which in a comparatively short time consolidated them until they formed a mass that at length became immovable, always adding more stone as required until the whole became solid; this foundation was carried up to the level of low-water mark. They then commenced the superstructure of masonry, of squared stone and brickwork cemented together by pozzolana or hydraulic mortar, which was best adapted to make the work permanent. The inside or quay wall was formed by first placing a close framework of timber in front and at the angle or slope at which the quay wall was to be formed. They then threw down a mass of pozzolana, lime, and small rubble stone, mixed together, between the wooden frames and the rubble stone which had been previously deposited to form the base of the mole. This in a comparatively short time become solid, as the mixture of pozzolana, lime, and stone possesses the quality of setting under water. When it had become sufficiently solid, the timber frame was removed and transferred to another section to form a continuation of the quay wall, and thus the whole line of inner quay wall which formed the roadway was made by backing the quay wall to its full height with rubble, and a parapet of masonry was erected on the outside; this superstructure, although rough, stood very well with occasional repairs. In this manner the mole was carried out to a great extent. A fine triumphal arch was erected at the end to commemorate the completion of the work.
It is singular that the same emperor should have constructed a like work in a similar situation and in the same manner at Civita Vecchia, on the opposite coast of Italy, after every attempt had been made to establish a port by his predecessors at Ostia, which was built at extraordinary expense, and has been filled up by the alluvial matter brought down by the Tiber and from the sea by the littoral currents, so that it is now three miles from the sea.
The principle of construction used in these works resembles a good deal the mode adopted by the Phœnicians at Tyre, and subsequently by the Carthaginians at Carthage, and by the moderns. The Romans also employed the hollow mole, that is, a mole constructed with arches, by means of which the current charged with alluvial matter was enabled to pass through the mole, and thus any deposit within or without the mole was to a great extent prevented. The harbour of Civita Vecchia remains serviceable at the present day for vessels drawing 20 feet of water, although, as may be naturally expected, a certain deposit has taken place during the lapse of so many centuries which requires to be dredged out occasionally. At Ancona only one pier was built on the south side, and consequently an eddy and stagnation took place on the north side, as the littoral current runs from south to north, and therefore there is a tendency to deposit on the north side. The French when masters of Italy commenced another mole on the north side, thus enclosing a considerable space of sea so as to form a close harbour, which no doubt is of great service; still, from the nature of the local circumstances, a certain deposit may always be expected. This, however, can be removed by dredging, and the harbour may always be preserved in a state of efficiency if the extent of trade will warrant the expenditure necessary for the purpose.
On reaching Rome, it is difficult to express the emotions I felt on a first sight of the Holy City, surrounded by the desolate Campagna, the Tiber rolling in front, the Castle of St. Angelo, and the numerous towers of churches rising out of the mass of houses, crowned by the gorgeous dome of St. Peter’s elevated in proud majesty above the whole, backed by the magnificent views of the ancient city, once the mistress of the world.
This most interesting, I may say, most thrilling, sight lay before me in all its solemn majesty. When I considered that it rose from a few insignificant shepherds’ hovels to imperial splendour, then became the prey of the barbarian hordes of the north, and lastly, the throne of the Catholic Christian world, I was awed by the wonderful decrees of Providence, and at the instability of all human grandeur. I lay restless all night; I could scarcely realize the fact that I was actually in this wonderful, all-absorbing city, to visit which from my childhood had been one of the greatest objects of my ambition. It would be vain to attempt to describe in detail its numerous splendid buildings, both ancient and modern, its museums, and its countless treasures of priceless art. I will merely remark that there is no city in the world more worthy of a visit than Rome, or where greater gratification and instruction can be derived; for example, the aqueducts and the Cloaca Maxima show how thoroughly the Romans understood the importance of sewerage and good water for the preservation of human life, an importance that is only now beginning to be recognized in England, while there still remains very much to be accomplished.
My friend Colonel Aitchison was obliged to hasten his departure. I then took lodgings in the Piazza de Spagna, and devoted myself to the study of the Italian language, architecture, and drawing, and in my leisure moments entered into society; and fortunately at that time there were assembled there some of the most distinguished characters in science, literature, and art, besides diplomatists and leaders of fashion, from the various capitals of Europe. Amongst the first may be mentioned the celebrated chemist and philosopher, Sir Humphry Davy, and his talented wife, under whose hospitable roof I passed many happy days, and at the same time received much valuable instruction. I made acquaintance with the Marchese Martinette, the scientific engineer, who at that time devised the extensive hydraulic works for the improvement of the rivers and drainage of the marsh-land districts of Bologna and Ferrara, from whom I derived much information. I also met the well-known antiquary, Sir W. Gell, who to his interesting memoir of Greece afterwards added much towards explaining the antiquities of Rome, and in his agreeable society I spent many a pleasant day. Dodwell too had just returned from Greece; and I made the acquaintance of that prince of sculptors, Canova, to whom my father had given me a letter of introduction. I frequently went to his studio, where he always received me with the greatest kindness. He was then at work on the model of his famous dying Madeleine, which struck me as a masterpiece of elegance and beauty, combined with the resignation and piety which so pre-eminently distinguishes it as a beautiful specimen of art. Nobody could be more kind, amiable, and modest in his manner than that distinguished sculptor.