Life of Robert Stephenson by William Pole: Chapter VIII (Volume 2)

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CHAPTER VIII. (Volume 2). The Great Victoria Bridge over the River St. Lawrence in Canada.

THIS was one of the last works on which Mr. Stephenson was engaged ; it was opened a few months after his death. It is the largest bridge in the world, and its design has involved engineering problems of a peculiar and unusual nature.

The Victoria Bridge carries the Grand Trunk Railway of Canada across the River St. Lawrfence, at a point near Montreal, where it is nearly two miles wide.

One of the most prominent features in the map of North America is the long line of water communication, which, commencing with the magnificent series of Lakes Superior, Michigan, Huron, Erie, and Ontario, descends from the latter of these by the River, the Estuary, and the Gulf of St. Lawrence, to the Atlantic Ocean.

From Lake Superior to a little below Lake Ontario this water line forms the frontier between Canada and the United States of America, but the boundary then retreats inland, on the south side, so that the lower part of the river, namely, from the 45th degree of latitude downwards, runs entirely within the British territory, and thus separates two parts of our colonial possessions which are of great richness and commercial value. On this part of the river also are situated the two large and important towns of Quebec and Montreal, the former at about 250 miles, and the latter at about 400 miles, above the mouth of the river, or rather above the Point des Monts, where the estuary may be considered to end and the gulf to begin.

To this grand river, and the fine extent of inland navigation above it, Canada is no doubt largely indebted for her prosperity and growth. But for nearly half the year the St. Lawrence is sealed up by frost; and during this time not only is all water traffic suspended between the different parts of the country, but Quebec and the other ports of the river and the lakes are deprived, so far as water communication is concerned, of that easy communication with the ocean on which their commercial prosperity so much depends.

But there are also difficulties attending the upper part of the navigation, even in summer. The Welland Canal, cut to form a navigable communication past the Niagara Falls, is of such contracted dimensions, that although vessels of 700 or 800 tons burthen can with ease get up to Lake Ontario, none greater than about 300 tons can reach the upper chain of lakes; and therefore, at this point, trans-shipment becomes necessary, both for the import and the export trade.

The obvious remedy for these disadvantages was a system of railways ; and accordingly at an early period the inhabitants expressed a wish to avail themselves of this mode of providing for their traffic. The first effort that took a practical shape was a fine of railway intended to connect the Fiver St. Lawrence, at a point opposite Montreal, with the great Atlantic harbour of Portland, distant about 230 miles to the SE. This line was called the ‘ Atlantic and St. Lawrence Railway; ’ it had to cross the frontier, and thus was partly Canadian and partly belonging to the United States. It was commenced about 1849; and by the middle of 1852, at which time its proprietorship changed hands, two lengths of it were opened, namely, from the St. Lawrence eastward to Sherbrooke, a distance of 80 miles; and from Portland northward about 90 miles, leaving a break in the middle of about 60 miles unfinished.

By this time, however, two other railways had been projected, one called the Quebec and Richmond Railway, commencing at Richmond on the last-named fine, and passing eastward to Quebec, a distance of about 85 miles; the other on the north bank of the River St. Lawrence, extending from Montreal westward to Kingston, about 170 miles, and called the Montreal and Kingston Railway. At the time referred to, the former of these was in progress, and for the latter, powers to construct had been obtained.

But it soon became evident that a more comprehensive scheme of railways was desirable, and the subject having excited interest in England during the summer of 1852, an examination of the country was made, at the request of the Provincial Government of Canada, by a firm of English contractors, with the view of carrying out such a project. The information they obtained led them to promote the formation of a company, with the object, first, of purchasing and completing the lines partly made or sanctioned; secondly, of adding other important extensions; and thirdly, of uniting the whole into one great system, by a gigantic bridge across the great water chain.

This vast enterprise is now completed, under the name of the Grand Trunk Railway of Canada; and it comprises upwards of 1200 miles of fine. About one-half of this is on the north side of the River St. Lawrence, extending from Montreal westward as far as Lake Huron; the remainder is on the south side, and has two main branches, one, the original Atlantic and St. Lawrence fine, passing southward to Portland; the other, the original Quebec and Richmond fine, extending eastward to Quebec. There is also a further extension, which, passing down the south bank of the St. Lawrence, ends at present at a place called Riviere du Loup. This latter branch was made partly to open out the south-eastern provinces of Canada, and to develop the great agricultural resources of that rich district; but it had also reference to a far more important ultimate purpose.

One of the main objects proposed to be attained by the introduction of railways into the colony was to open a communication between the interior of the country and the sea, during that long period of the year when the St. Lawrence is closed by frost. At present, the Grand Trunk Railway only accomplishes this by its connexion with the United States harbour of Portland; but it is evident that circumstances might arise which would render this mode of communication unavailable; and therefore it would be highly expedient to complete the new roadway to the sea entirely through British territory; a measure, the expediency of which has often been forcibly urged. The most obvious means of attaining this end would be to continue the hne last mentioned from the present temporary eastern terminus, about 400 miles further in a south-easterly direction, namely, across New Brunswick and Nova Scotia to the fine British port of Halifax, which would put the whole of Canada in communication with the ocean, at all times of the year, in a manner independent of any foreign power.

The Grand Trunk Railway is, however, even in its present incomplete state, a remarkable national work. It traverses British North America in one unbroken line for half the breadth of a continent; it connects and associates together the several wide-lying dependencies of the British Crown ; it affords throughout the year to the inhabitants of the wonderful valley through which it passes constant means of communication and transport which nature had denied them; it opens out the rich prairie country of the Far West; and it unites the whole of these vast regions with the neighbouring territories of America, and with the great maritime pathway of the world.

Our attention must now, however, be confined to the great bridge, by which the connection between the two main divisions of the line has been secured. The necessity for such a bridge became urgent when the railways had made some progress, and Mr. Stephenson’s own remarks on this point will be hereafter inserted. Suffice it here to say that from the head of Lake Superior to the Atlantic Ocean, a distance of more than 1500 miles, there was not any bridge across the great water chain, excepting at the Niagara gorge; and that, therefore, the key to the province would be obviously in other hands, if the railway communication could not be completed between the North and the South sides.

The engineering problems to be solved in the erection of such a bridge near Montreal, were of a peculiar kind. Although, at the point where it was desired to cross, the river was very wide, and the current was strong, yet the water was comparatively shallow, and it seemed unlikely that the nature of the bed would offer much trouble with the foundations. And since, after the experience gained in the Britannia and Conway Bridges, the use of iron for spanning large openings had become easy, the construction of a railway bridge would have involved nothing beyond a question of expense, had it not been for a difficulty peculiar to the locality, and one scarcely known in English engineering—the extraordinary effects produced upon the river by the great severity of the Canadian winter.

To explain these phenomena it will be sufficient to quote the description of them given by Mr. W. E. Logan, F.G.S., in the Proceedings of the Geological Society of London for 1842. He says

The frosts commence about the end of November, and a margin of ice of some strength soon forms along the shores; and wherever the water is still, it is immediately cased over. The first barrier completed across the river, below Montreal, is usually formed about Christmas, at the entrance of Lake St. Peter, where the St. Lawrence is divided into a multitude of channels by low alluvial islands. This barrier is rapidly increased by extensive fields of drift ice, enormous quantities of which are heaped upon or forced under, the stationary mass.

The space left for the water to flow being thus greatly diminished, a perceptible rise in the river takes place, and by the time that the ice becomes stationary at the foot of St. Mary’s current, opposite Montreal, the waters in the harbour have usually risen several feet, and as the packing rapidly proceeds, they soon attain the height of 20 and sometimes 26 feet above the summer level.

It is at this period that the grandest glacial phenomena are presented. In consequence of the packing and piling of the ice, as well as the accumulation of the moistened snow of the season, and the freezing of the whole into a solid body, sometimes more than 20 feet thick, the water suddenly rises, and lifting a wide expanse of the entire covering of the St. Lawrence, urges it forward with terrific violence, piling up the rended masses on the banks of the narrower parts of the river, to the height of 40 or 50 feet.

In front of Montreal is a newly-built revetoment, the top of which is 23 feet above the summer level of the river; but the ice broken by it accumulates on the surrounding terrace, and before the wall was erected the adjacent buildings were endangered, the ice sometimes breaking in at the windows of the second floor, even 200 feet from the margin of the river.

In one instance, a warehouse of considerable strength and magnitude having been erected without this protection, the great moving sheet of river ice pushed it over as if it had been a house of cards; and in another case, where a similarly situated and equally extensive warehouse, 4 or 5 stories high, had been provided with a range of oaken piles, placed at an angle of less than 45°, the drift ice rose up the inclined plane, and after meeting the walls of the building, fell back, and formed, in a few minutes, an enormous but protecting rampart. In some years the ice accumulated nearly as high as the roof of the warehouse.

Several of these grand glacial movements [locally termed ‘ shovings ’] take place, sometimes at intervals of many days, but occasionally of only a few hours, the permanent setting being indicated by a longitudinal opening of considerable extent in some part of St. Mary’s current. This opening, which is never afterwards frozen over, even when the temperature is 30° below zero of Fahrenheit, is due to the water having formed a free subglacial as well as superficial passage, in consequence of its own action and the cessation in the supply of drifting ice.

From this period the waters gradually subside, but seldom or never to their summer level; and when they have attained their minimum, the trough of the St. Lawrence exhibits a glacial landscape of undulating hills and valleys of ice.

This description will make it clear that the great engineering difficulty to be overcome in building a bridge across the river was, so to establish the piers (of which a large number were required), that while they should offer the least possible resistance to the progress of the ice down the stream, they should be strong enough safely to withstand the enormous and almost unprecedented destructive force to which they must be exposed from its violent action.

No doubt the idea that it would be advantageous to bridge over the St. Lawrence must have occurred to the Canadians at a very early period of the history of the colony; but we find no published intimation that such a scheme was considered practicable until, in June 1846, discussions were raised as to the proper site for the terminus of the Atlantic and St. Lawrence Railway, then in progress. At this time, the Honourable John Young, an energetic citizen of Montreal, and one of the railway directors, published a newspaper article, pointing out that the passage of the river by the railway would afford great facilities for the traffic, and expressing a confident opinion that the erection of a bridge would be ‘ perfectly practicable,’ at a certain point named, coinciding very nearly with the site on which the bridge now stands.

The suggestion seems to have made a favourable impression, for in September of the same year the directors of the Atlantic and St. Lawrence Railway authorised Mr. A. C. Morton, their engineer, to cause a survey to be made for the purpose of ascertaining the practicability of building a bridge and of estimating its probable cost. Mr. Morton took soundings, but the nature of his report does not appear to have been made public. In the meantime, a committee of citizens of Montreal was formed to investigate the same subject, and they employed Mr. E. H. Gay, of Pennsylvania, then engineer of the Columbia and Philadelphia Railway, to make another survey. His report was given in December 1846, accompanied by plans and estimates. He disapproved of the fine selected by Mr. Morton, but considered it practicable to build a bridge across another site, at the moderate expense of about 525,000 dollars; giving, however, no provision for the navigation of the river by masted vessels.

About this time a general commercial depression seems to have prevailed throughout the province, and nothing further was done till June 1851, when, on the promotion of the railway from Montreal to Kingston, which was proposed to join the Atlantic and St. Lawrence line, the two companies agreed that another survey should be made for a bridge; and accordingly, Mr. Thomas C. Keefer, the engineer of the Kingston line, was commissioned to undertake it. He proceeded with the work in this and the following year, but his progress was delayed for want of funds. He wrote a report on the subject, which was published in 1853,§§ but the date of its presentation is not recorded; it was an able document, containing much valuable information, and Mr. Stephenson expressed a high estimation of Mr. Keefer’s labours.

Meantime, however, the interest in the work had passed into other hands. The St. Lawrence and Atlantic line had become a part of the more comprehensive scheme, the Grand Trunk Railway; and in September 1852 the Kingston Company also waived their charter in favour of the same great enterprise, on condition that the new proprietors would construct the bridge.

When the examinations of the country were made, in the spring of 1852, with a view to the formation of the Grand Trunk Railway Company, the promoters had engaged as their engineer Mr. A. M. Ross, who had previously been one of the resident engineers under Mr. Stephenson, on the Chester and Holyhead Railway. He had charge of the masonry of the Conway Tubular Bridge, and Mr. Stephenson had a high opinion of his skill in that department of engineering. The question of the bridge over the St. Lawrence formed naturally one of the most prominent subjects of enquiry, and in July 1852, Mr. Young, who has been already mentioned as the original projector of the bridge, and who had ever been its most energetic promoter, took Mr. Boss to examine the various points of crossing that had been proposed; and it is stated that, when near the site subsequently adopted, Mr. Boss suggested that the iron tubular beam principle would be applicable for the superstructure. In October 1852, immediately after the Grand Trunk Company had taken the matter into their own hands, surveys were commenced on their behalf. It was probably at this time that Mr. Keefer handed over, for the use of the new company, the extensive and valuable information he had obtained. About the end of this year Mr. Boss returned to England.

The great importance of the bridge, the large expenditure it involved, the various opinions that existed as to its practicability, and the great difficulties and risks connected with its construction in such a position, decided the board of directors, previous to bringing it before the public, to consult Mr. Robert Stephenson, whose high opinion it was deemed of great importance to obtain.

With this view Mr. Boss, after his return to England, laid before Mr. Stephenson all the information collected both by Mr. Keefer and by himself. The subject had some months’ careful consideration, and after many tentative plans and estimates had been prepared, on March 18, 1853, Mr. Stephenson communicated to the Hon. John Boss, Speaker of the Canadian House of Assembly, a design similar in its principal features to that ultimately carried out.

Mr. A. M. Ross returned to Canada in April, and soon after his arrival, the same design was submitted to the Board of Railway Commissioners at Quebec, with a joint report explaining its general features, and of which the following is a copy :

Grand Trunk Railway, Champ de Mars, Montreal: June 6, 1853.

To the Honourable the Board of Railway Commissioners, Quebec.

GENTLEMEN,— We beg herewith to transmit for your approval, a design for the proposed Victoria Bridge for carrying the railways across the River St. Lawrence, at this place.

On the map accompanying this report the precise locality is clearly defined : the figures marked upon the map indicate the depth of summer water, determined by soundings carefully taken; the shoals, which are numerous and intricate, are also outlined as nearly as they could be ascertained.

From an inspection of the map it will be seen that the site selected for the bridge embraces as wide a range of deep water as can be obtained by any line crossing the river, in the vicinity chosen as the most eligible for this important structure, and where the width across from bank to bank is 8,600 feet, the deep water channel occupying about one-seventh of this width.

The abutments of the proposed structure are placed 6,588 feet apart, and the piers (twenty-four in number) occupy 450 feet of this space, leaving 6,138 feet clear waterway, which is equal to 93 per cent, of the whole, having an average summer depth of 9 feet water, the navigable channel being 15| feet deep.

It is proposed to fill up the intervening space between the abutments and the shores on either side (700 feet in length on the St. Lambert, and 1,300 feet on the Point St. Charles side) with solid embankment composed of stone. The form of this embankment is delineated upon the drawing.

The piers are proposed to be built of solid masonry, of such form and proportions as will be in every way calculated to withstand any pressure to which they may be liable from the moving ice.

An explanatory diagram of these is shewn upon the drawing.

The superstructure is proposed to be of wrought iron, constructed in every respect on the same principle as the Britannia Bridge over the Menai Straits, on the Chester and Holyhead Railway, and in uniform spans of 242 feet, excepting that over the navigable channel, which is intended to be 330 feet.

The strength is calculated to resist four times the actual load to be sustained, and equal to ten times the moving load, reckoned at one ton to the lineal foot.

The clear headway above summer water is placed at 60 feet for the whole width of the centre opening, a height which, from the best information we can obtain, is ample for passage of any craft which can come down the rapids.

From the pier on either side of the centre opening, height gradually diminishes at the rate of 1 in 130 to extreme end of the tubes, and from this point falls towards shores at the rate of 1 in 100, to suit the local requirements connected with the railways on either side of the river.

The leading characteristics of the design may be stated briefly as follow: That only one-fifteenth of the space between the abutments is occupied by the supporting piers. That the piers are of the form best suited for withstanding any force to which they may be exposed from the moving ice, and for severing the floating masses in their progress. That a wide deep-water channel is selected as affording the greatest security in reference to the passage of the ice, and that the materials of construction are of that permanently enduring character as will require a minimum amount for efficient maintenance.

With a due regard to every consideration involved in this important measure the accompanying plans are respectfully submitted for approval.(Signed)

The Railway Board, on receiving this report, instructed Mr. Killaby, the Assistant Commissioner of Public Works, to examine the plans, of which he reported his entire approval. He discussed at some length the height of headway proposed, as some persons were of opinion it should not be less than 100 feet; but he shewed it was so improbable that vessels requiring this height of headway could descend by the rapids from the lakes above, that it would not be requisite to inflict on the bridge the great and permanent injury of raising it so high. Mr. Killaby’s report was adopted by the Government, and the proposed bridge formally approved; and an intimation of the approval was sent to Mr. Stephenson and Mr. Ross on August 19, 1853.

Although, however, the design of the bridge was thus arranged, with tolerable precision, it was felt that the weight of Mr. Stephenson’s authority would be much enhanced if he actually visited the site, and took personal cognizance of all the various circumstances affecting the measure. He accordingly left England about the middle of July, and remained in Canada till September. This visit enabled him to enter much more fully into the details of the subject than before, and his more matured views upon it were expressed in a letter to the directors, dated May 2, 1854, which is of sufficient importance to warrant its insertion entire :—

24 Great George Street, Westminster: May 2, 1854.

GENTLEMEX,— Absence from England, and other unexpected circumstances, have prevented my sooner laying before you the results of my visit to Canada last autumn, for the purpose of conferring with your engineer-in-chief, Mr. Alexander Boss, respecting the Victoria Bridge across the River St. Lawrence, in the vicinity of Montreal.

The subject will naturally render itself into three parts, viz:—

First—The description of bridge best adapted for the situation.

Second—The selection of a proper site.

Thirdly—The necessity for such a structure.

Regarding the first point, I do not feel called upon to enter on a discussion of the different opinions which have been expressed by engineers, both in England and America, as to the comparative merits of different classes of bridges, and more especially as between the suspension and tubular principles, when large spans become a matter of necessity. It is known to me that in one case in the United States a common suspension bridge has been applied to railway purposes; but from the information in my possession, from a high engineering authority in that country, the work alluded to can scarcely be looked upon as a permanent, substantial, and safe structure. Its flexibility, I was informed, was truly alarming, and although another structure of this kind is in process of construction near Niagara, in which great skill has been shown in designing means for neutralising this tendency to flexibility, I am of opinion that no system of trussing applicable to a platform suspended from chains will prove either durable or efficient, unless it be carried to such an extent as to approach in dimensions a tube, fit itself for the passage of railway trains through it. Such bridge may doubtless be successfully, and perhaps with propriety, adopted in some situations; but I am convinced that even in such situations, while they will in first cost fall little short of wrought-iron tubes, they will be more expensive to maintain, and far inferior in efficiency and safety.

I cannot hesitate, therefore, to recommend the adoption of a tubular bridge, similar in all essential particulars to that of the Britannia over the Menai Straits in this country; and it must be observed that, the essential features being , the same, although the length much exceeds that of the work alluded to, none of the formidable difficulties which surrounded its erection will be involved in the present instance. In the Britannia, the two larger openings were each 460 feet, whereas in the proposed Victoria there is only one large opening of 330 feet, all the rest being 240 feet. In the construction of the latter, there is also every facility for the erection of scaffolding which will admit of the tubes being constructed in their permanent position, thus avoiding both the precarious and expensive process of floating, and afterwards lifting the tubes to the final level by hydraulic pressure.

In speaking of these facilities, it is a most agreeable and satisfactory duty to put on record that the Government Engineering Department has, throughout the consideration of this important question, exhibited the most friendly spirit, and done everything in its power to remove several onerous conditions, which were at one time spoken of as necessary, before official sanction would be given for the construction of the work.

On my arrival in Canada, I found that Mr. A. M. Ross had collected so much information bearing on the subject of the site of the bridge, that my task was comparatively an easy one.

Amongst the inhabitants of Montreal, I found two opinions existing on this point—somewhat conflicting: the one side maintaining that the river should be crossed immediately on the lower side of the city, where the principal channel is much narrower than elsewhere, and where also the island of St. Helen’s would shorten the length of the bridge; the other seeming to be in favour of crossing a little below Nunn’s Island.

Sections of the bed of the river at both points had been prepared, and a careful study of these left no doubt on my mind that the latter was decidedly the one to be adopted.

In addition, however, to the simple question of the best site for the construction of a bridge across the St. Lawrence, my attention was specially called to the feasibility of erecting and maintaining such a structure during the breaking up of the ice in spring, when results take place which appear to every observer indicative of forces almost irresistible; and, therefore, such as would be likely to destroy any piers built for the support of a bridge. I have not myself had the advantage of witnessing these remarkable phenomena, but have endeavoured to realise them in my mind as far as practicable, by conversation with those to whom they are familiar; and, in addition to this, I have read and studied with great pleasure an admirable and most graphic description by Mr. Logan, of the whole of the varied conditions of the river, from the commencement of the formation of ice to its breaking up and clearing away in spring. To this memoir I am much indebted for a clear comprehension of the formidable tumult that takes place at different times amongst the huge masses of ice on the surface of the river, and which must strike the eye as if irresistible forces were in operation, or such as, at all events, would put all calculations at defiance.

This is no doubt the first impression on the mind of the observer; but more mature reflection on the subject soon points out the source from which all the forces displayed must originate.

The origin of these powers is simply the gravity of the mass occupying the surface of the water, with a given declivity up to a point where the river is again clear of ice; which, in this case, is at the Lachine Falls. This is unquestionably the maximum amount of force that can come into play; but its effect is evidently greatly reduced—partly by the ice attaching itself to the shores, and partly by its grounding upon the bed of the river. Such modifications of the forces are clearly beyond the reach of calculation, as no correct data can be obtained for their estimation; but if we proceed by omitting all consideration of those circumstances which tend to reduce the greatest force that can be exerted, a sufficiently safe result is arrived at.

In thus treating the subject of the forces that may be occasionally applied to the piers of the proposed bridge, I am fully alive to the many other circumstances which may occasionally combine in such a manner as apparently to produce severe and extraordinary pressure at points on the mass of ice or upon the shore; and, consequently, upon the individual piers of a bridge. Many inquiries were made respecting this particular view, but no facts were elicited indicative of forces existing at all approaching to that which I have regarded as the source and the maximum of the pressure that can at any time come into operation affecting the bridge.

I do not think it necessary to go into detail respecting the precise form and construction of the piers, and shall merely state that in forming the design care has been taken to bear in mind the expedients which have hitherto been used and found successful in protecting bridges exposed to the severe tests of a Canadian winter, and the breaking up of the ice of frozen rivers.

I now come to the last point, viz. the necessity for this large and costly bridge.

Before entering on the expenditure of £1,400,000 upon one work in any system of railways, it is of course necessary to consider the bearing which it has upon the entire undertaking if carried out, and also the effect which its postponement is likely to produce.

These questions appear to me to be very simple, and free from any difficulty.

An extensive series of railways in Canada, on the north side of the St. Lawrence, is developing itself rapidly; part of it is already in operation, a large portion fast progressing, and other lines in contemplation, the commencement of which must speedily take place.

The commerce of this extensive and productive country has scarcely any outlet at present but through the St. Lawrence, which is sealed up during six months of the year, and therefore very imperfectly answers the purposes of a great commercial thoroughfare.

Experience, both in this and other countries where railways have come into rivalry with the best navigable rivers, has demonstrated, beyond the possibility of question, that this new description of locomotion is capable of superseding water carriage wherever economy and despatch are required; and even where the latter is of little importance, the capabilities of a railway, properly managed, may still be made available simply for economy.

The great object, however, of the Canadian system of railways is not to compete with the River St. Lawrence, which will continue to accommodate a certain portion of the traffic of the country, but to bring those rich provinces into direct and easy connection with all the ports on the east coast of the Atlantic, from Halifax to Boston, and even New York—and consequently through these ports nearer to Europe.

If the line of railway communication be permitted to remain severed by the St. Lawrence, it is obvious that the benefits which the system is calculated to confer upon Canada must remain in a great extent nugatory and of a local character.

The province will be comparatively insulated, and cut off from that coast to which her commerce naturally tends; the traffic from the west must either continue to adopt the water communication, or, what is more probable — nay, I should say, certain—it would cross into the United States by those lines nearly completed to Buffalo, crossing the river near Niagara.

No one who has visited the country and made himself acquainted only partially with the tendencies of the trade which is growing up on all sides in Upper Canada, can fail to perceive, that if vigorous steps be not taken to render the railway communication with the eastern coast through Lower Canada uninterrupted, the whole of the produce of Upper Canada will find its way to the coast through other channels ; and the system of lines now comprised in your undertaking will be deprived of that traffic upon which you have very reasonably calculated.

In short, I cannot conceive anything so fatal to the satisfactory development of your railway as the postponement of the bridge across the river at Montreal. The line cannot, in my opinion, fulfil its object of being the high road for Canadian produce until this work is completed; and looking at the enormous extent of rich and prosperous country which your system intersects, and at the amount of capital which has been already, or is in progress or prospect of being expended, there is in my mind no room for question as to the expediency—indeed, the absolute necessity of the completion of this bridge, upon which, I am persuaded, the successful issue of your great undertaking mainly depends.

I am, gentlemen. Yours faithfully, (Signed) EGBERT STEPHENSON.

To the Directors of the Grand Trunk Railway of Canada,

Meantime, active preparations had been made for the construction of the bridge. The detailed surveys had been progressing all the year; the visit of Mr. Stephenson and his conferences with Mr. Hoss on the spot had tended to settle more conclusively the details of the design ; and on September 29, 1853, the contract was let for the construction of the bridge. The contractors were Messrs. William Jackson, Samuel Morton Peto, Thomas Brassey, and Edward Ladd Betts; and the contract sum for the entire work was £1,400,000.

The iron work of the superstructure had to be made in England, and the designs for this were entrusted by Mr. Stephenson to his cousin, Mr. George Robert Stephenson, who carried them out in all their details, and superintended the entire manufacture at the ‘ Canada ’ iron works, Birkenhead.

Some material changes were made in the superstructure subsequently to the original design. The first proposal was, in all the openings except three, to place the road on the top of the tubes, as Mr. Stephenson had done in the Egyptian bridges, particulars of which Mr. Eoss took with him to Canada. In the middle or navigable opening, in order to gain headway, the trains were to run through the tube, as in the Britannia Bridge, and the adjoining openings on each side were treated similarly, so as to form a continuous tubular girder of three spans. On further consideration, however, it was thought better to adopt this latter plan in all the tubes, and they were altered.

Other changes were also made in regard to the construction of the girders. The central tube, being of larger span than the others, had been originally designed with a cellular top, like the Britannia and Conway Bridges; but Mr. Stephenson having gained more confidence in simpler means of giving rigidity, substituted plain plates, with stiffening bars of angle and T iron.

Further, in the original design, the tubes were connected together in lengths of four spans each ; these were afterwards reduced to two spans each, at Mr. G. R. Stephenson’s suggestion, in order to diminish the tendency to roll down the incline.

About two years after the letting of the contract, and when the works were considerably advanced, a controversy arose as to the fitness of the design for the bridge. It was represented to the Directors that the plans adopted were extravagantly expensive, and that by using a different kind of girder for the superstructure, and different methods of founding the piers, a sufficient bridge might be erected for about one-fourth the cost.

Mr. Stephenson replied to these assertions at considerable length, in a report dated November 3,1855, and the opinions of Mr. Brunel, Mr. Edwin Clark, and Mr. Ross, were also laid before the Directors in confirmation of Mr. Stephenson’s views.

It appears that the Board were satisfied as to the propriety of the designs, and the works were allowed to go on. It is unnecessary, therefore, to enlarge further on these discussions, but the following passages from Mr. Stephenson’s report throw so much light on his views as to warrant their insertion :—

It would evidently be unreasonable to expect that amongst professional men an absolute identity of opinion should exist, either in reference to the general design, or in many of the details of a work intended to meet such unusually formidable natural difficulties as are to be contended with in the construction of a bridge across the St. Lawrence.

You will remember that at the time I first entered upon the consideration of the subject, these difficulties were deemed by many well acquainted with the locality, and publicly stated by them, to be, if not insurmountable, at all events of so serious a character as to render the undertaking a very precarious one.

The information I received respecting these obstacles, when my attention was first drawn to this project, was so striking, that I reserved forming an opinion until I had visited the spot, had well considered all the detailed information which Mr. Alexander Ross had collected during several months’ previous residence in the country, and had heard the opinion of many intelligent residents, regarding the forces exhibited by the movements of huge masses of ice during the opening of the river in spring.

The facts gathered from these sources fully convinced me that, although the undertaking was practicable, the forces brought into action by floating ice, as described, were of a formidable nature, and could only be effectively counteracted by a structure of a most solid and massive kind.

All the information which has been collected since I made my first report has only tended to confirm the impressions by which I was then guided.

For the sake of clearness and simplicity, the consideration of the design maybe divided into four parts: first, the approaches; secondly, the foundations; thirdly, the upper masonry; and fourthly, the superstructure or roadway.

The approaches—extending in length to 700 feet on the south, or St. Lambert side, and 1,300 feet on the Point St. Charles side—consist of solid embankments, formed of large masses of stone, heaped up, and faced on the sloping sides with rubble masonry.

The up-stream side of these embankments is formed into a hollow shelving slope, the upper portion of which is a circular curve of 60 feet radius, and the lower portion, or foot of the slope, has a straight incline of 3 to 1; while the down-stream side, which is not exposed to the direct action of the floating ice, has a slope of 1 to 1. These embankments are being constructed in a very solid and durable manner, and from their extending along that portion of the river only where the depth at summer level is not more than 2 feet 6 inches, the navigation is not interrupted, and a great protection is, by their means, afforded to the city from the effect of the ‘ shoves ’ of ice which are known to be so detrimental to its frontage.

Advantage has also been taken of the shallow depth of water in constructing the abutments, which are each 242 feet in length, and consist of masonry of the same description as that of the piers, which I am about to describe; and from their being erected in such a small depth of water, their foundations do not require any extraordinary means for their construction.

The foundations, as you are aware, are fortunately on solid rock, in no place at a great depth below the summer level of the water in the river.

Various methods of constructing the foundations suggested themselves, and were carefully considered; but without deciding upon any particular method of proceeding, it was assumed that the diving bell, or such modifications of it, on a larger scale, as have been recently employed with great success in situations not very dissimilar, would be most expedient. The contractors, however, or rather the superintendent, Mr. Hodges, in conjunction with Mr. Boss, after much consideration on the spot, devised another system of laying the foundations, which was by means of floating ‘ coffer dams,’ so contrived that the usual difficulty in applying coffer-dams for rock foundations would be, it was hoped, in a great measure obviated. When in Montreal, I examined a model of this contrivance, and quite approved of its application, without feeling certain that it would materially reduce the expense of construction below that of the system assumed to be adopted by Mr. Ross and myself, in making the estimate. In approving of the method proposed by Mr. Hodges, I was actuated by the feeling that the engineers would not be justified in controlling the contractors in the adoption of such means as they might consider most economical to themselves, so long as the soundness and stability of the work were in no way affected.

This new method has been hitherto acted upon with such new modifications as experience has suggested from time to time, during the progress of the work, and although successfully, I learn from the contractors that experience has proved the bed of the river to be far more irregular than was at first supposed —presenting, instead of tolerably uniform ledges of rock, large loose fragments, which are strewed about, and cause much inconvenience and delay.

They are therefore necessitated to vary their mode of proceeding to meet these new circumstances; and it may be stated that all observations, up to this time, show the propriety, notwithstanding the difficulty with dams, of carrying the ashlar masonry of the piers down to a solid rock.

We are now brought to the question as to the upper masonry. This question is exceedingly important, since the cost of the masonry constitutes upwards of 50 per cent, of the total estimated cost of the bridge and approaches. The amount of the item of expenditure for the masonry is clearly dependent upon the number of piers, which is again regulated by the spans between them.

The width of the openings in bridges is frequently influenced, and sometimes absolutely governed, by peculiarities of site. In the present case, however, the spans, with the exception of the middle one, are decided by a comparison with the cost of the piers; for it is evident that so soon as the increased expense in the roadway, by enlarging the spans, balances the economy produced by lessening the number of piers, any further increase of span would be wasteful.

Calculations based upon this principle of reasoning, coupled to some extent with considerations based upon the advantages to be derived from having all the tubes as nearly alike as possible, have proved that the spans which have been adopted in the present design for all the side openings, viz. 242 feet, have produced the greatest economy. The centre span has been made 330 feet, not only for the purpose of giving every possible facility for the navigation, but because that span is very nearly the width of the centre and principal deep channel of the stream.

It may perhaps appear to some, in examining the design, that a saving might be effected in the masonry by abandoning the inclined planes, which are added to the up side of each pier, for the purpose of arresting the ice, and termed ‘ icebreakers.’

In European rivers, and I believe in those of America also, these ‘ ice-breakers ’ are usually placed a little way in advance of, of rather above, the piers of the bridges, with a view of saving them from injury by the ice shelving up above the level of (frequently on to) the roadway.

In the case of the Victoria Bridge, the level of the roadway is far above that to which the ice ever reaches; and as the ordinary plan of ‘ ice-breakers,’ composed of timber and stone, would be much larger in bulk, though of a rougher character, than those which are now added to the piers, I have reason to believe that they would be equally costly, besides requiring constant annual reparation. It was therefore decided to make them a part of the structure itself, as is now being done.

To convey some idea of the magnitude of ordinary ‘icebreakers ’ placed on the up-side of the pier, and to enable you to form some notion of their cost, I cannot do better than quote the following from the excellent report addressed to the Honourable John Young, by Mr. Thomas C. Keefer, whose experience in such matters, from long residence in the country, entitles his opinion as to the proper character of such works to confidence:-—

‘The plan I have proposed contemplates the planting of very large “ cribs ” or wooden “ shoes,” covering an area of about one-fourth of an acre each, and leaving a clear passage between them of about 240 feet—a width which will allow ordinary rafts to float broadside between them. These “islands” of timber and stone will have a rectangular well left open in the middle of their width, toward their lower ends, out of which will rise the solid masonry towers, supporting the weight of the superstructure, and resting on the rocky bed of the river. This enclosure of solid crib-work all round the masonry, yet detached from it, will receive the shock, pressure and grinding of the ice, and yield to a certain extent, by its elasticity, without communicating the shock to the masonry piers. These cribs, if damaged, can be repaired with facility, and, from their cohesive powers, will resist the action of the ice better than ordinary masonry. During construction, they will serve as coffer-dams, and being formed of the cheapest materials, their value as service-ground or platforms for the use of machinery, the moving of scows, &c. Their application to the sides of the piers is with particular reference to preventing the ice from reaching the spring of the arches, which will he the lowest and most exposed part of the superstructure, if wood be used.’

In the first design for the Victoria Bridge, ‘ice-breakers,’ very similar to the above-described by Mr. Keefer, were introduced ; but subsequently the arrangement was changed, partly with a view of gaining the assistance of the whole weight of the bridge to resist the pressure of the ice (but it became fixed), and partly for the purpose of obviating the considerable annual outlay.

I have not data at hand to estimate correctly the cost of the ordinary ‘ ice-breakers,’ as described; but I have little or no doubt that, as I before stated, they would have required to have been large and substantial masses of stone and timber, which in amount of cost would be scarcely less than, if not equal to, the inclined planes of masonry which have been added to the up-side of the piers.

It is now necessary for me to say a word or two upon the style of workmanship. It consists simply of solid ashlar; and considering the severe pressure and abrasion to which it will be subjected by the grinding of the ice, and the excessively low temperature to which it will be for months periodically exposed, I am confident that it is not executed with more solidity than prudence absolutely demands; and considering the difference of the rates of wages in Canada and this country, I believe the price of the work will come out nearly the same as any similar work let (here) by competition.

The description and style of the masonry is precisely similar to that adopted in the Britannia Bridge; the material is the same, and the facility of obtaining it is not in any important degree dissimilar.

The following is a brief description of this remarkable structure.

The site of the bridge is at the lower end of a small lake, or enlargement of the stream, about a mile above Montreal Harbour. At this point the River St. Lawrence is, from shore to shore, 8,660 feet, or nearly a mile and three quarters wide.

The level of the river varies at different parts of the year. From about the middle of April to the end of December it remains at what is called summer level, only varying a foot or two above or below a certain line ; but during the other 3.5 months, when it is covered with ice, it rises about 10 feet higher, and at the beginning and end of the period, sometimes as much as 15 feet higher.

The depth of the river is but shallow, varying from 5 to 15 feet below summer water level.

The current in the principal channels runs at the rate of seven or eight miles an hour.

The bed of the river consists of slate rock, which lies bare near the shore, but is covered towards the centre to a depth of 12 or 14 feet with a deposit of clay and gravel, so hard that it was at first mistaken for the rock itself. Large boulders, varying in weight from 1 to 20 tons, lie scattered profusely about, often appearing above the summer water level; the whole of this overlying matter had to be cleared away at the site of the piers, so that their foundations might rest upon the solid rock below.

The approaches are carried some distance into the river on each side, partly in embankments and partly in abutments of masonry, so that the length of the bridge proper is about 6,650 feet. This is divided by stone piers into twenty-five openings, of which the middle one, serving as the principal channel for the navigation, is 330 feet wide, and the remainder are each 242 feet wide.

The bridge is constructed only for one line of railway, the superstructure being a single iron tube extending from end to end, through the interior of which the trains pass, in the same manner as in the Britannia Bridge.

The height of the bottom of the tube above summer water level is about 36 feet at the abutments, rising by a gradient of 1 in 130 to 60 feet at the centre opening.

Of the twenty-four piers of the bridge, all except the two middle ones are alike in horizontal dimensions, but they increase in height towards the centre, according to the gradient of the tubes.

( See PDF version for drawings)

Fig. 9 is a side elevation of one of the piers, and will give an idea of their construction. They are built of solid masonry, composed of heavy stones, from 5 to 20 tons each. They are founded with their footings resting on the solid rock, and are carried up, with the dimensions of about 90 feet wide by 23 feet thick, to within 6 feet of summer water level, at which point the ice-breaking plane begins. This is a slope of masonry, on the up-side of the pier, inclining backwards at an angle of about 45° with the horizontal, until it reaches a height of about 20 feet above the highest or winter level of the river. The face of this slope is pointed, hke a cutwater, and the masonry is formed of large sohd stones worked perfectly smooth, and strongly bound together internally with iron cramps, to resist the enormous thrust upon them. When the large floes, or sheets of ice moving down the river, come in contact with these massive constructions, they are turned upwards by the slopes, and breaking down or toppling over by their own weight on each side of the cutwater ridges, they fall into the open spaces between the piers, and so pass harmlessly down the river.

Above the ice slopes the piers are carried on, measuring about 33 feet wide by 16 feet thick, up to the level at which the tubes rest upon them.

The two piers at the sides of the centre opening are of the same general form and width as the others, but of larger dimensions, being 30 feet thick at the base, and 24 feet at the tube level.

The stone used in the piers is a hard grey limestone, obtained partly from quarries at a place called Pont Claire, near the north bank of the river, about sixteen miles above Montreal, and partly from an island in Lake Champlain, whence it was brought by the River Richelieu and the Champlain Railway. Although coming from points widely separated, these two kinds of stone are of very similar quality.

The quantity of masonry in the piers and abutments is about 2,713,000 cubic feet.

The tubes for the smaller spans are 16 feet wide, and 18 feet 6 inches high at the abutments, increased to 22 feet in the middle of the bridge. They are made of wrought iron plates, on a similar principle to those of the Britannia Bridge, except that the top and bottom are not cellular, but are formed simply of layers of plates riveted together, and stiffened by ribs, gussets, and T irons.

The centre tube has the same width as the others, but is 23 feet high, and the top and bottom have extra strength and stiffening.

The tubes are united in pairs, the middle of each double length being fixed firmly down upon a pier, while the two ends, resting on the two adjacent piers, are left free to slide upon rollers, to allow for expansion and contraction ; a small interstice being left for this purpose between them and the next adjoining tubes at either extremity.

No advantage is, however, taken of the principle of continuity, each half being designed as if it were an independent beam.

A single line of railway, 5 feet 6 inches gauge, is laid on longitudinal sleepers in the middle of the tube, and a footway 4 feet wide is placed on one side of it for the passage of the railway servants.

The tubes are lighted by holes cut in the sides at every 60 feet, and they are protected by a light covering from the weather.

The weight of iron in the whole line of tube is 9,044 tons.

There were above three thousand workmen employed in the construction of the bridge, and the contractor’s plant comprised four locomotive engines, together with six steamers and seventy-five barges, having a collective tonnage of 12,000 tons. Upwards of two millions and a quarter of cubic feet of timber were used in the dams, platforms, and other temporary works.

The carrying out of this great design in Canada, comprising the getting in of the foundations, the building of the piers, and the erection of the iron superstructure, was a work of no ordinary magnitude and responsibility. Mr. Stephenson gave occasional advice in this matter, and sent out working drawings, accompanied with complete instructions for the putting together of the tubes ; but the credit for the successful accomplishment of this portion of the work is principally due to Mr. Hoss and to Mr. Hodges, the engineer sent out by the contractors. The work occupied between six and seven years, and a sketch of the principal events it comprised will complete the notice of the structure.

The general plan of the works having been decided on, operations commenced in the winter of 1853. The river being frozen over, and having assumed its ordinary winter height, the ice was cleared and levelled along the fine of the bridge; the sites of the piers were carefully set out, and permanently marked by iron pins driven down into the bed of the river; soundings were made in their immediate localities, and the most eligible channels for boats and barges were selected and defined.

The plan originally proposed for founding the piers was by means of large floating ring-dams of the nature of caissons. Each of these was to be large enough to encircle a whole pier; it was to be built on the shore, floated out to the site, moored and secured in position; then scuttled, sunk, and puddled, and the interior pumped dry to allow of the construction of the masonry. The only available time for operations in the river was during the summer months ; and as no temporary works could be left in the river during the ice-season, the dams were so devised that, when the masonry within them was completed, they could be readily floated again, and taken to a place of safety, to be used for other piers in the ensuing spring.

Each caisson was 188 feet long and 90 feet wide externally, the internal chamber being 102 feet by 42 ; the front part or bow was made wedge-shaped, to stem the current, and the stern or hinder part was movable, to allow of its being taken away after the building of the pier.

Dams on a similar principle were to be used for the formation of the north abutment. Six of these were constructed on the shore during the winter of 1853 ; and being launched in May 1854, were towed up to the site of the abutment, where the actual works of the bridge were flrst commenced.

The dam was completed and laid dry, and the masonry was commenced in August 1854; the work had been raised 6 feet above summer water-level when the winter set in, and all further operations were necessarily suspended.

In June, 1854, the dam was got into position for the first pier; the masonry was begun in July, and the pier was finished before the end of the working season. The dam of the second pier was in place in July, and the masonry was erected to a height of 4 feet above summer level before the winter.

But now doubts began to be entertained whether the plan of founding by caisson-dams was the best possible. The dams when floating only drew 18 inches of water, but even with this light draught great difficulty was experienced in navigating the shallow rapid waters with so huge a mass; and still greater trouble was encountered in getting them into position. It was, therefore, decided that an attempt should be made to found the next piers by dams constructed of a species of open timber framing, called ‘ crib work,’ and much used in Canada. Local contractors skilled in this kind of work were accordingly engaged, and though great difficulties were met with from the velocity of the stream, the dam to No. 5 pier was completed during the working season.

Accidental delays had prevented the dams of Nos. 1 and 2 piers from being removed before the ice began to form: it was hoped, by strongly protecting them, they might be enabled to stand through the winter; but this hope was futile, for on the 4th of January, 1855, a general and violent movement of the ice took place, which completely destroyed and carried them away. Other injury was done also to the abutment dam, and to the embanked approach ; but the permanent masonry of the two piers and the abutment stood perfectly well, as did also the new crib work dam of No. 5 pier.

During the ensuing winter, little was done beyond providing timber and quarrying stone. In the summer of 1855 the works were resumed ; the north abutment was carried up to high-water level; the south abutment commenced ; No. 2 pier finished; No. 5 pier commenced ; and crib work dams made and fixed for three other piers.

At the end of 1856, seven piers had been finished at the north end, and two at the south end, and the masonry of the south abutment had been brought up to a high level.

In 1857 five more piers were erected on the south side, and two commenced on the north.

It was, however, now felt that the completion of the bridge was likely to be protracted for many years, owing to the shortness of the working season. The available time each year was, at the outside, six months ; the earlier portion was occupied in preparing for the setting of stone, which could, therefore, seldom begin before the middle of August, and all mortar work ceased by the end of November, when the frosts set in ; so that sixteen weeks constituted the whole working season for executing the masonry of the bridge. This fact induced, during the year 1857, the adoption of a very ingenious device, of bedding the ashlar masonry in felt instead of in mortar, as had been previously done with success at St. Anne’s Bridge over the river Ottawa; and thus the erection of the masonry could be prosecuted during the winter. Strips of asphalted felt, about three inches in width, were laid along the whole of the front of the masonry, at such a distance from the edge that the work might be effectually pointed. On each of the cross joints similar strips were placed, as likewise at the back of the stones. As soon as one course of ashlar was laid, it was dressed perfectly fair on the bed to a straight edge for the reception of another course, which was superimposed in a similar manner, the backing being laid dry and packed as closely as possible. Open spaces or flues were left, about one foot square, throughout the whole height of the pier. The work was completed in this manner during the winter, and as soon as the weather permitted, and the frost was fairly out of the stone, the piers were carefully pointed and the whole of the interior well grouted from the flues. The whole thus became one solid mass, the clear water, which filtered through the joints, showing very accurately the progress of the grouting. This admirable contrivance hastened considerably the completion of the bridge.

During this year also was commenced the erection of the iron superstructure, portions of which had been already received. A timber staging or platform, of great strength and stiffness, and supported at two intermediate points by temporary piled piers, was fixed over the first opening, and upon this the tube was erected. The whole of the ironwork had been accurately manufactured and temporarily put together at the contractors’ works at Birkenhead, under Mr. G. E. Stephenson’s supervision, and every piece was carefully punched and marked before it left England, so as to define its proper place in the structure. Owing to the accuracy with which this was done, the various pieces, during the erection in Canada, were fitted and riveted together without difficulty. The bottom of the tube was first completed, and adjusted to level and camber; the sides were next added, commencing at the centre, and as these advanced towards each end, the plating of the top closely followed.

When the tube was finished, its supports were struck away, it was allowed to take its own bearing, and the piers and the temporary platform were removed for use in another place. The first tube was completed during the summer of 1857, and a platform was also fixed for the erection of the twenty-fifth tube, the first from the south end; and the ironwork of this was also fixed during the winter of the same year.

In the next year, 1858, great progress was made, the number of finished piers being increased to twenty-one, and two others being brought up to above summer level. The remaining pier (the eleventh from the north side) was purposely delayed to give water-way for the navigation, until the large centre opening should be completed. Some modifications were made in the construction and arrangement of the dams, and some accidents and failures occurred, but strong efforts were made to push on the work, and, on the whole, the year’s progress was very satisfactory.

In this year also five more tubes were erected on the north side, and five on the south side, while the platform was prepared for the large central tube.

In the beginning of the next year the erection of this tube was commenced, and continued day and night; and it was finished and the supports removed by the end of March, only a few hours before the ice broke up. The most strenuous exertions were necessary to accomplish this, for it was evident that, if the general movement of the ice took place before the tube was clear of the temporary staging, it would risk the carrying away of the intermediate temporary piers, and the consequent entire destruction of the tube; and honourable testimony is borne to the energy and zeal with which every man concerned exerted himself, under great difficulties, and in the most inclement weather, to contribute to the desired result.

In May the dam was commenced for the last remaining pier, the eleventh from the north side ; but a few days afterwards it was carried away by two large timber rafts which came floating down the river, and ran foul of this and one adjoining pier ; many men, on the rafts and the bridge works, were thrown into the stream, but fortunately all were saved, though the destruction of property was considerable. A new dam was immediately commenced, and the pier was completed in September, and the fixing of the iron superstructure now proceeded rapidly.

In March 1859, Mr. Stephenson sent out Mr. B. P. Stockman, (who had taken an active part under Mr. G. E. Stephenson in the construction of the tubes,) accompanied by Mr. Samuel P. Bidder, the former traffic manager of the Railway Company, for the purpose of inspecting the progress of the iron superstructure; and a few months later, shortly before his death, Mr. Stephenson expressed a further wish that another visit should be paid to Canada, to examine and test the bridge on his behalf, previously to its being opened for traffic.

With this view, in November 1859, Mr. Stockman again went to Canada, accompanied by Mr. G. B. Bruce, who had been a former assistant of Mr. Stephenson’s. Having examined the entire bridge, and carefully tested the tubes by running through them heavily loaded trains, they presented a report on December 17th, in which they recommended that, after a few small matters were finished, the Directors should accept the bridge from the hands of the Contractors as being completed satisfactorily. Mr. A. M. Hoss, who had assisted in the experiments, concurred in the report; the bridge was opened for public traffic two days afterwards, and the formal inauguration by H.R.H. the Prince of Wales, who visited Canada for the purpose, took place on August 25th, 1860.

The period of six years, which was occupied in the execution of this great work, seems by no means long, when we consider the peculiar nature of the difficulties which had to be encountered, and which by the perseverance and energy of the persons engaged were successfully overcome. The extraordinary rapidity of the stream in summer, and the violent action of the ice in winter, were elements of a magnitude seldom entering into the operations of ordinary river engineering; and although the water was comparatively shallow, the nature of the bottom, and the immense boulders scattered over it, involved great difficulties. The rigour of the winter was also a heavy trial, not only in reducing the available working time, but also in its effect on the men engaged, who, for the most part, being new to the climate, were but ill prepared to brave its severity. In the summer the scorching heat struck them down by coups de soleil; while in the winter they were frost-bitten and blinded by the glare of the snow ; the thermometer was often 50° below freezing point, and during the winter of 1858, when such exertion was made to get the centre tube finished, and when consequently night-work became necessary, the sufferings of the men were extreme. If there was any wind, the portions of the body exposed to it became instantly frozen, and the men had, therefore, to work in thick gloves and heavy coats; fur caps covered their ears, and heavy handkerchiefs were worn over the faces, leaving only a small portion free for vision. It often happened, when the wind blew up stream, that the men would become covered with icicles, and be obliged to leave their work. Notwithstanding all precautions, scores of men were frozen in their hands, feet, ears, and faces, and many had to go to hospital in consequence, but, fortunately, so prompt were the remedial arrangements that no serious consequences occurred. In the summer of 1854 the cholera made sad havoc among the men ; in some cases nearly a third of the number employed were sick at one time, and many of those who were not attacked ran away from the pestilence, so that the best men were lost to the work. To these misfortunes were added the difficulties of great general scarcity of labour ; the necessity of bringing out workmen at great expense from England; frequent strikes and insubordination among the men; and the discouragement caused by hostile parties among the inhabitants, who declared the attempt to build a bridge to be a defiance of Providence, and prognosticated its utter failure. In 1855 the cost of the works became so much increased by the general financial depression consequent on the Russian War, that the abandonment of the contract was seriously contemplated ; and in a subsequent year great doubts were entertained whether the financial means of the Company would justify its continuance, nearly the whole of a valuable season being lost in consequence. Peculiar difficulties also arose from the isolation of the piers, for as there was no space at any of them for stacking or sorting the stones, every course had to be prepared at the quay, selected, and shipped upon barges, exactly in the order and at the time required. It followed, therefore, that a course, or often even a stone, wrongly sent, or a barge getting aground, or the loss or damage of any of the peculiarly shaped stones, many of which were of great size, caused the whole of the workmen, material, and plant, to remain idle till the want could be supplied, which often took a week or more.

However, all these difficulties were ultimately overcome, and the bridge remains a lasting monument, not only of the engineering knowledge and skill which designed it, but of the energy and perseverance of those who had to carry the design into execution.

• This chapter is contributed by Professor Pole.

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