- L-v_li1»T^U winiy. 
 
 DESCRIPTION 
 
 'f^^^iU..i^ . .<• >%<:,-/:-■' 
 
 OF 
 
 THE INTERNATIONAL BRIDGE, 
 
 CONSTRUCTED OVER 
 
 THE NIAGARA RIVER, 
 
 ( 
 
 NEAR i 
 
 FORT ERIE, CANADA, and BUFFALO, U.S. of AMERICA. 
 
 TORONTO : 
 COPP, CLARK & CO., PRINTERS, 67 & 69, COLBORNE STREET. 
 
 «8 73- 
 
 J 
 
i 
 
lu THE HlliHT lloNOl HAULK 
 
 Silt FllEDERICK TEMPLE, EARL OF PUFFERIX, K.T., K.C.B., &c., &c. 
 Governou-Gkm;i!ai. ok Caxada. 
 
 My Lord, 
 
 IVfien I asked permission to dedicate these pages to you, I was so 
 much impressed with the interest taken />i/ ijour Lordship in the Works of the 
 International Dridije and their detail, that I did not feel, as I do now, I was presuming 
 upon t/our good nature, and arer-estimating the value of mg little book. 
 
 The ready and graeious manner in which mg request was acceded to, assures me, 
 however, tliat gonr Lordship saw no presumption in it. I have, therefore, some pride 
 in inscribing these pages to you, and am convinced that, containing, as tliey do, an 
 account of a work of some public importance to Canada, they will possess an interest 
 to your Lordship beyond their own merits. 
 
 I have the honour to be. 
 My Lord, 
 Your /wardship's most obedient Servant, 
 
 C. S. GZOWSKI. 
 
 Toronto, 30th September, IS 73. 
 
•"HI ll^tH!Wl«"^pii 
 
r R J^ F A C E 
 
 In the construction of the International Bridge, difficulties and obstacles presented 
 themselves which, I believe, rarely if ever occurred together before in any similar work. 
 They wer j as follows : 
 
 Depth of water nearly 50 feet, with frequent, sudden and considerable fluctuations 
 
 Rapid and changeable current, varying from five-and-a-half to nearly twelve miles 
 an hour. 
 
 Unreliable anchorage. 
 
 E.xposure of caissons, with all the appliances and plant, to destruction from rafts of 
 unmanageable and enormous dimensions during the entire season of navigation. 
 
 Impossibility of carrying on the work during the winter on account of enormous 
 masses of floating ice. 
 
 Treacherous bottom. 
 
 Limited amount of capital furnished for construction of the work. 
 
 Some of these obstacles were quite unexpected ; and while, in overcoming al! 
 the difficulties, means were used well known to Engineers, in many instances new 
 applications were made of such means, and in others plans entirely novel were designed 
 and executed. 
 
 These difficulties, and my intimacy with them, caused me, as they presented 
 themselves, much anxiety. 
 
 The contract for building the Bridge having been taken by the firm of which I 
 am a member, all practical operations devolved upon myself; and as the cost of the 
 undertaking was limited in price, much thought was necessarily devoted to overcoming 
 every obstacle economically as well as perfectly. 
 
 In the belief that a description of the construction of so important a work cannot 
 but interest the public, and that much may be found in it of practical utility to my 
 own profession, I am induced to publish the following pages. 
 
 I must add that the skill, zeal and industry of the Staff connected with the work 
 have been beyond praise. But for them many difficulties which were soon overcome 
 would have proved to be great and serious obstacles ; and to their active co-operation 
 I am mainly indebted for the early completion of the Bridge. 
 

 TAJJLE OF CONTEISTS. 
 
 CHAP T , R I. Page. 
 
 History of the Bridge -. , 
 
 CHAPTER II. 
 
 Characteristics of Niagara River and Location of the Bridge .... iq 
 
 CHAPTER III. 
 
 Progress of the Work— Directorate and Staff employed 23 
 
 CHAPTER IV. 
 
 Foundations and Subaqueous Work 26 
 
 CHAPTER V. 
 
 Masonry .g 
 
 CHAPTER VI. 
 
 Superstructure, and Mode of raising it 54 
 
 CHAPTER VII. 
 Ice ,. 
 
 63 
 
LIST OF TLATES. 
 
 Xo. 
 
 Plan of Location '• 
 
 General Plan of Bridge *^' 
 
 Currents, Velocities, and Water Gauge '•'• 
 
 Outer Caisson, No. 5 ^^• 
 
 Water-tight Caisson V. 
 
 Anchorage ^'• 
 
 Abutment No. 2 'V- 
 
 Pier No. 2 VIII. 
 
 „ No. 5 IX. 
 
 „ No. 6 x- 
 
 „ No. 7 ^^■ 
 
 Abutment No. 3- XII. 
 
 190-ft. Girder and Details XIII. 
 
 240-ft. Girder and Details XIV. 
 
 Main River and Canal Draw Girder XV. 
 
 Turn-table and Locking Gear -- XVI. 
 
 Method adopted for Erecting Superstructure over Deep Water Spans - - xvil. 
 
 Diagram of Strains XVIII. 
 
 Traveller - XIX. 
 
 Saw used for Cutting off Piles under Water ------- XX. 
 
 Dredging Machinery XXI. 
 
INTERNATIONAL BRIDGE. 
 
 CIIATTEU I. 
 
 H I STO K V (J K T II I: li R I DO K . 
 
 Tho first Bridge over erected to carry liailway trains across the waters dividing 
 Canada and the United Stat(\s, was tlio great Siisi)en.sion Bridge, aliout two miles 
 below Niagara Falls. Tliis Bridge was completed and opened for Railway trallic in 
 tho year 18:)4. It connected the (ireat Western Railway, tlu-n ninning to the Niagara 
 frontier, with the Now York Central Itailroad to Boston and Now York. 
 
 The completion of that Bridge gave a great in.petns to the consideration of tho 
 question of bridging navigable waters on tho American continent ; and railwav brid-'os 
 Lave since l)een constructed across the Hudson IJiver at All)any, and at several points 
 both across the Mississipj)i and Missouri IJivers. It gave Inrth also to tho idea of 
 tho great International Bridge at Bulfalo, now completed, which was designed to 
 facilitate interconnnunication between tho llaihvays of Canada and tho United States 
 at tho important City of Buffalo. 
 
 Charters for the construction of this work were passed in the year 1857, by the 
 Parliament of Canada, and by the Legislature of the State of New York. 
 
 They were obtained by the Railway interests upon the two sides of the River, 
 and were intended to connect the .system of Railways then being constructed in 
 
 Canada— converging at Fort Erie, at the eastern extremity of Lake Erie with tho 
 
 Railways through the State of New York centreing in tlie City of Buffalo. 
 
 These Charters lay dormant for several years, owing to the impossibility of securing 
 the funds necessary for tho construction of so great a work. 
 
 The New York Central Railroad, which has one of its termini at Buffalo, secured 
 a connection, upon the south shore of Lake Erie, with the Lake Shore Railroad 
 running through to Chicago. It had also, by tho Suspension Bridge already named, 
 a direct connection with the Railway system of Canada, extending from Clifton to 
 Windsor, opposite Detroit. 
 
 The parties first interested, in Canada, in the construction of tho BufTsilo Bridge, 
 wore connected with tho Buffivlo, Brantford and Goderich Railway, a lino starting from 
 Fort Erie, and running across the peninsula of Upper Canada to Goderich upon Lake 
 Huron. This was, however, for many years a weak Corporation, and became ultimately 
 
bankrupt, neccssitatiiif;- tho reorganizfition of its affairs, wliich finally passed into the 
 hands of a now Company -tlii' title lioing t'liani,n>(l from its ori>j;inal oiu' of " lluflalo' 
 ]irantford and (iodericii Kitilway," to " liufl'alo and Lako Jlui'on liaihvay." 
 
 This latter Company was owned ahnosc entirely in England. Considerahlo sums 
 were advaneed for the eonipletion of the line, so that it was at length finished, from 
 Fort Erie to (ioderieh, crossing; in its conrse the Great Western Railway at Paris, and 
 the (Irand Trnidv Railway at Stratford. I'.y these nu-ans it olitained a eonnoetion 
 with the West; Iml alllioii^h slreunons ell'orts u > re made liy its friends, they were 
 unable to raise the neressary funds for tlie eoHsiruriion of the Uridye. 
 
 The Railways I'entreiiiy- at IJullalo, althongh greatly desiring the eonipletion of the 
 work, failed, from various eanses, to lend lliat material assistance wliieli was indispensable. 
 Varions plans were from time to ti'ie proposed to obtain nmnicipal aid fi'om the City 
 of IJulUdo, and Aets were passed liy the Eegislature of tlie Sta.te of New York, in 
 the year ISJH, authorizing tho City, upon certain eonditions, to guarantee interest upon 
 a portion of tho Capital Stoek of the Interuiitional JJridge Comi)any ; but this, after 
 nmeh negotiation, was never carried into ojteration. 
 
 Matters remahied in this state for several years. Tiie l')nlfahi and T.ake Ilunm 
 Company, like its predeee.ssors, fell into hnaiicial dillieulties. and for several years tho 
 control of it was eompeted for liy tiie (ireat Western and < irand Trunk Companies, 
 Ultimately an agreement was made lielween the Jlntfalo and Lake Huron and (Jraud 
 Trunk Companies, l)y winch tho latter ti)ok a leas(> of the ]5ulfalo antl Lake Huron 
 line, ac(juiring the entire control of the proiu-i'ly for a specilied rental. 
 
 These arrangements being concluded, vigorous efforts were agaiu made to revive 
 the scheme lor eoustructing the luteruatioual Bridge, but which weri' not sucees.sful 
 for several years. 
 
 At length the agreements between the Grand Trunk and IJntfalo and Lake Huron 
 Companies were reduced to a practical ami simple eondititm, and tlu' whole .sanctioned 
 by tiie Parliament of tlie Dominion of Canada. Cpon these arrangenu'nts lieing 
 comiileted, and the Grand Trunk Comj)any authorized by Parliament to guarantee 
 interest upon the cost of tho JJridgo to tho extent of tl'O.OOO sterling per annum, 
 the Capital for its construction was at length raised in England in tho year 1870. 
 
 The total amount of Capital thus raised amounted to . . £'_'7-,")i)(> 
 
 The amount of ]?()nds being '2(t."),ro(» 
 
 And ol' Preforenco .Share t,'ai)ital (J(},8((() 
 
 By Acts passed by the Parliament of Canada, and by the Legishiture of the State 
 of New York, the two Companies, which had be«n Incorporateil by those Legi.slaturps, 
 
were authorized to amalgamate aad form one Company, under the title of "The 
 International Bridge Company," with a nominal Capital of 31,i)(K),()0(). They were 
 authorized, in the same way, to issue Bonds to the extent of 61,()0(),()()0. 
 
 The issue of the Securities before mentioned was successfully carried out at a net 
 price of rather more than 90. 
 
 As soon as these financial an-angcments liad been completed, a Contract was let 
 by the International Bridge Company, with the concurrence of the Grand Trunk 
 Railway Company, to INIcssrs. C. S. Gzowski and D. L. j\Iacpherson, of Toronto. The 
 Contract was for the completion of the Bridge from the Canada shore at Fort Erie, 
 to the American shore at Black Rock, and was for the sum of §1,000,000. The 
 Contract required that the Bridge should bo constructed with stone piers and iron 
 superstructure, with the Draw-bridges in the main river and across the artificial navigation 
 at Black Rock in such a manner as might be required by the proper authorities. It 
 should hero be .stated that in order to avoid all question of interference between the 
 rights of Great Britain and the United States — the territories of which the Niagara 
 River divides — the Act passed by the Parliament of Canada authorizing the construction 
 of the Bridge was reserved for Her INIajosty's assent, which was given after the whole 
 matter had been fully investigated by the Imperial authorities. In like manner, in 
 order to give full legality to the authority granted by the State of New York, an 
 Act of Congress was passed at Washington, by which the United States GoAcrnment 
 agreed to the construction of the Bridge, and declared it to be a post route of the 
 United States. 
 
 This Act required that the Bridge, in regard to its fonn of construction and 
 the size and position of the Draw-bridges, shoidd be subject to the approval of a 
 Board of United States Military Engineers, who were instructed to examine into the 
 question, and the plans proposed for the Bridge were in due coiu-se submitted to 
 their consideration. 
 
 They made various suggestions in regard to the position of the Drav-bridges, 
 which were adopted, and the Bridge is now completed in accordance with their views, 
 and under the instructions which their Report contained. These changes involved 
 certain departm-es from the original Contract. They altered the position of the Draw 
 in the main river, and to a certain extent added to the cost of constructing the work. 
 
 The Draw-bridge in the main river is a double one, worked upon a pivot or 
 centre pier, the whole length of the Draw being 362 feet, giving two openings on 
 each side of the pivot pier of 160 feet. 
 
 The Draw-bridge across the artificial navigation of Black Rock Harbour was 
 settled by the Commissioners for the Eric Canal, which navigation forms the outlet 
 
6 
 
 of the canal into Buffalo, and the Draw-bridge here consists of a Bridge worked 
 from a centre or pivot pier with two openings on each side of the pivot of 90 feet 
 each. 
 
 The same Contractors also took tlie contract for completing the works necessary 
 to connect the Bridge with the New Yorlv Central Railway at Black Rock Harbour, 
 and also about 3^ miles of railway iVom the Canada end of the Bridge to form a 
 connection with the main lino of the Buflalo and Lake Huron line. The contract 
 did not include engineering expenses or the necessary land to bo acquired for the 
 construction of the works. 
 
 Upon these preliminary arrangements being made, the necessary engineering staff 
 was appointed : the Enginecr-in-Chicf being ]\Ir. E. V. llaniuiford, the Engineer of 
 the Grand Trunk Railway, who had for his resident Engineer, Mr. Joseph Hobson, 
 (who has resided continuously upon tlie spot) with the necessary staff of assistants. 
 
 The length of the Bridge from the abntmcnt on the Canada shore to the abutment 
 on Squaw Island, which lies between the main river and Black Rock, is 1,967^ feet. 
 The distance across Squaw Island is 1,167 feet, and from the ainxtment on Squaw 
 Island to the abutment on the main shore on the American side is 617 feet, making 
 the total length of the Bridge 3,05 l.i, feet. 
 
 A full description of the Bridge and Avorks will be found in the following pages, 
 but it may be well to give here a brief general outline. 
 
 From the abutment on the Canada .shore, the Bridge is carried by six piers to 
 the end of the main Draw. The first three spans are of 197 feet each, and the 
 next three 248 feet each. The Draw-bridge rests upon a pivot pier, which is No. 
 7, and the eastern end of the Draw rests upon the last pier in the river, which is 
 No. 8. From that pier to the abutment on Squaw Island is a span of 197 feet. 
 The depth of water at each of these piers is as follows : 
 
 No. 1 10 feet, 
 
 2 -ji) '< 
 
 3 33 " 
 
 4 47 " 
 
 5 48 " 
 
 tJ 3(» " 
 
 7 IC, " 
 
 8 !» " 
 
It is not npcossnry to doscribo hero the mode of constructing the caissons on 
 which the piors are l)uilt, but it is safe to say that the plan adopted is a novel 
 one in on^incoiiiiff works, and ilisplays great skill on the part of the Engineers who 
 designed and exocutod it. Across S(|uaw Island the Bridge is carried at present 
 by a lino of trestle work twenty feet high, which is to be filled in from a cutting 
 on the Canada shore, but which could not be done until the Bridge enabled trains 
 to take the material to tlio spot where it was to be deposited. It is intended to 
 widen considerably the present structure across Squaw Island as it is filled in with 
 earth, so as to give room for three or four linos of rails between the two Bridges, 
 which will add materially to tlio amount of trailic which can be passed from one side 
 of the river to tlie other. The Draw-bridgf s across the main river and the canal are 
 both worketl by .steam power, and the large Draw, 364 feet in length, can be opened 
 or shut in rather ie.s.s than 60 seconds. 
 
 The current in the river, which added very largely to the difficulty of executing 
 the work, nin.s on an average about f),^ miles an hour, and under the influence of a 
 strong southerly wind blowing down I,ake Erie, will run as fast as 12 miles an hour. 
 
 In order to prevent the possibility of any damage arising either to the Bridge 
 or to vessels navigating the river owing to tiie strength of this current, the law 
 requires that a Steam Tug be always maintained during the season of navigation by 
 the Bridge Conqjany, to aid vessels and rafts in passing through the Draw. 
 
 Considerable discussion arose during the construction of these works from their 
 novelty, and from the peculiar conditions under which they had to be executed, in regard 
 to thj stability of the structure. The first three piers, from the Canada side, have now 
 been down during three wintens, — in two of which the ice has been heavier and stronger 
 than had been known for many previous years, and far above the average. Four of the 
 other piers, including tiioso in the deepest water, and where the greatest strain caused 
 by the tlirectiou of tlie current will come upon tliem from ice, have been down throughout 
 last winter, which, for severity of cold and strength of ice, was much above the average. 
 It is, therefore, satisfactory to be al)le to say that the piers, which had to encounter 
 these exceptioiudly severe winters and runs of ice, have shown not the smallest 
 settlement or injury, and have i)roved beyond all doubt the perfect stability of the 
 works, and their capacity to bear any strain that, under any circumstances, can ever 
 be placed upon them. In point of fact, their strength is greatly in excess of that 
 usually required in works of this kiml. They have been well designed and executed, 
 and in every resix^ct form a work of the very best class. There are always persons 
 who, in a work of any magnitude, are ready to give expression to fears and doubts 
 as to its stability and strength. 
 
8 
 
 This, of course, is more commonly the case in matters wliero the novelty of the 
 work and peculiarity of position are out of tlio usual course of things, as these 
 conditions afford the greatest latitude to those who aio always ready to find fault, 
 who are, as a rule, exccUont critics, however ineiJicient they may bo as authors or 
 designers. The great Victoria Bridge at Montreal, built under the direction of the 
 late Robert Stephenson, was condemned in advance by persons of the class referred 
 to, as being incapable of >vithstanding the strain to which tlio runs of ice would 
 subject it. The critics in that case, like tliose in that of the International Bridge at 
 Buffalo, have been sternly rel>ukc(l by the inexorable logic of events, which affords 
 another proof, if any were wanting, of the facility with which people can find fault. 
 
 The iron superstructure of this Bridge has been constiiicted at the extensive 
 Iron Works at Phoenix\-ille, Pennsylvania. It is known as the " Pratt" or quadrangular 
 truss, and is of a kind being very generally adopted in the United States and 
 Canada. The two largo Bridges on the Intercolonial Railway in Canada, across 
 the Restigouche and Miramichi Rivers, are being constructed by the .same firm, 
 and on the same plan. Every part of the material employed in the constiniction 
 of this Bridge was subjected, at the Phrenixville Work.=i, to the severest tests 
 before being allowei. o form part of the .superstructure. Tlie quality of the iron is 
 omnistakably equal to that of any iron to bo found in tlie world, and the workmanship 
 in every part has been subjected to most careful inspection, and is of the very 
 highest quality. The appearance of the Bridge is exceedingly light and graceful. 
 It derives its great strength from the depths of the trass, and presents no great 
 surface to the wind, as is the case Avith the Victoria Bridge at Montreal. 
 
 Since the first Acts were passed authorising the construction of the Bridge, the 
 Railway system both of Canada and the United States has rapidly grown, and in 
 consequence there will be a very large traffic indeed over the Bridge. On the American 
 side both the New York Central and New York and Erie Railroads have one of their 
 tenmni at Buffalo, and both will have a connection with the Bridge. 
 
 There are Railways also now running fi-om Buft'alo to I'hiladelphia, Baltimore, 
 and into the Iron and Coal Districts of Pennsylvania and Ohio. 
 
 On the Canada side of this Bridge will bo the only outlet across the NiagSTa 
 frontier for the traffic of the Grand Trunk Railway, which extends through the whole 
 of Western Canada, and has one of its termini at Detroit. It connects at that city 
 with the Michigan Central Railway, thus forming a direct connectitm between Buffalo 
 and Chicago, and the vast Western country which has Railway communication with 
 that great centre. During the season of navigation lines of Propellers nm at Sarnia 
 in connection with the Grand Ti-unk Railway to and from Chicago, Milwaukee, Green 
 
Bay, l\Iuckiimc, Sanlt 8ti'. Marii', Dulutli, Fort William, i*tc. This routo cuts off the 
 great detour formed l)y the Detroit liiver and Luke Erie, and these vessels will i)our 
 into Sarnia vast ((uantitios of produce for transport across the neck of country and 
 the ]>ridj^e, to IJuffalo. 
 
 The (Ireat Western Itailway — seeing the great IJailway centre now forming at 
 Biitfaln, and in order to relieve the strain upon its own Suspension Bridge, which 
 is taxed nearly to its utmost capacity — are building, and liave nearly completed, a 
 duplication of thi-ir line from (ilencoe to the International liridge, and will thus send 
 over the IWidge a veiy considerable portion of the largo business now passing over 
 the Great Western Railway. 
 
 A third iini' of railway through the peninsula of Upper Canada, the Canada 
 Southern Railway, which runs liom Andierstburg to l'"ort Erie, h.as been under 
 construction during tin? last two years, and is now completed, waiting to send its 
 tratlic also over the International Bridge. 
 
 At Andierstburg that Itailway will cross the Detroit River by means of a ferry, 
 forming a connection with the Toledo, Waliasli and Western Kailway, and, it is also 
 understood, will form connections with IJailways running to Chicago, so securing a 
 large trallic, the eastern outlet for which can only be over the International Bridge. 
 On both sides of the Iii\'er, therefore, there arc now converging several thousand miles 
 of Railway, m hich will tinil this Biidgo the main, if not the only, outlet for their traflBc. 
 There seems no reason to doubt, therefore, that the capacity of the Bridge will bo 
 fully tested by the amount of tratlic that is to pass over it, which, from the stability 
 of its works and the speed at which trains can run, will be very large. The cost 
 of the Bridge, including the connections with the New York Central Railroad, and 
 with the main line of the Grand Trunk Railway, including all the extra outlay occasioned 
 by the dilHculties in the foundation of some of the piers, and the changes recomnu'uded 
 by the United States Engineers, adding also Interest upon the outlay during construction, 
 will not quite reach the sum of .'?1,.")0(>,(I(M), or about i'otUt.DOO sterling. 
 
 There are few, if any, works of the same magnitude, constructed of the same 
 permanent materials, and executed under such great difliculties, which have been 
 completed at so small a cost. 
 
 For the moile and details in which that construction has been carried on, the 
 reader is referred to the pages which follow. 
 
CHAPTER II. 
 
 CHARACTERISTICS OF NIALiARA KIVKK A.Mi LOCATION' Oi TIIF. liKinci-.. 
 
 Wliile the advantajics that woiiM accrue from a Bridfjo across the Niagara River near 
 Buffalo were obvious, the practicability of the proi)osal to erect one was by no means so 
 apparent. 
 
 The difficulties to be overcome in buihling a permanent and rigid structure across 
 the River were so great, that the project was viewed, even by the boldest, with some 
 degree of distrust. The facts, arguments, and conjectures of the advocates of the 
 scheme were certainly not devoid of plausibility, but at the same time there hung over 
 it an element of extreme uncertainty, which only the actual success of the work has been 
 able fully to dispel. 
 
 It is true, the Niagara River is free from some of the i)ecu]iarities of the Missouri 
 and Mississippi Rivers, which have rendered the work of bridging them memorable 
 triumphs of engineering skill. It has not the moving san.ls, the unstable bottom, the 
 ever-changing channel, and the periodically high floods which are among the charac- 
 teristics of those Rivers. It has, however, diflieultios wiiich are peculiarly furmidable, 
 and which sufficiently wan-anted the doubt of the proposition to cross it with a 
 permanent structure. 
 
 The great depth of water, the force of the current, and the ice runs, which 
 were believed by those best accpuiinted with the River to be almost, if not altogether, 
 irresistible, vnth the sudden riscjs of water,— which, although not of great height and 
 duration, are as dangerous and destructive in some respects as the freshets in many 
 other Rivers— presented obstacles of no light character to the successful erection of 
 a Bridge. 
 
 The Niagara River being of short length, and a .strait ccmnecting link Ijetwceii 
 Lakes Erie and Ontario, the elevation of its surface and the fluctuations in the 
 height of the River are coincident with those in Lake Erie, which, leaving out 
 of consideration the sudden rises and falls caused by storms, &c., do not vary more 
 than two feet. 
 
 The general level of the River being, therefore, nearly permanent, there is very 
 little danger of the re(/i»ien of the stream being disturbed, even were its beil much 
 looser and more easily moved than it is. But when it was ascertained that the pcution 
 of the bed of the River which is not rock consists of a heavy clay, with a light covering 
 of gravel over it, the probability of danger from any serious scour was considered to lie 
 
11 
 
 reduced to an almost infiiiitosiniiil extent, as all that coiiM happen would be the removal 
 by the current of the gravel overlaying the clay which is too compact to be at all 
 ad'ectod by it. In tact, the i)ernuuuMit character ot the Itiver bed and banks was 
 one (if the few favourable features tliat lirought the scheme of bridging the lliver, at 
 this point, within the bounds of probability. 
 
 Although tlie uualtciable nutaio of the channel and bed of the Niagartr River 
 gave assurance of the pormancnce of any structure thrown across it, so far as stability 
 depends upon good foundations and unyielding Ijanks, yet the accidental disturbances 
 to which the water in tiie liivcr at the IJridge site is subject, in consequence of 
 its proximity to Lake Eric, aie of such a description, that the actual construction 
 of the liridgc had to be carried on in the face of constantly recurring ditticulties ; 
 while, as already stateil, the general elevation of the water, extending over long 
 periods, is not great, the occasional rises, lasting for a few hours, are sudden 
 and of great violence. 
 
 A heavy north-east wind causes the lliver to fall nearly two feet in the 
 course of less than iialf a day, Ijy forcing the water from the entrance of the River 
 Inick hito the Lake ; on the other hand, a south-west gale, by bringing the whole 
 " fetch " of the Lake to bear upon its outlet, has the etfect of raising, occasionally, 
 the water at the Bridge from four to live feet above its ordinary level in less than 
 as many hours. Such a rise taking place increases the surface iuchnation of the 
 River and accelerates the current, which at times has been known to attain at the 
 Bridge site a sj)eed not less than twelve miles an hour. 
 
 Although the sudden rises in the surface of tiie River are invariably caused 
 by winds blowing down the Lake, it is noticed as a curious circumstance, that the 
 water generally rises a little in advance of the wind ; that is to say, before the wind, 
 which is producing the increased heiglit of water, actually reaches the east end of 
 Lake Erie. 
 
 The normal velocity of the water is high, as the surface inclination of the River 
 between Lake Erie and the head of the Rapids altove Niagara Falls — a distance of 
 nineteen miles nearly — is tifteen feet. Tiie iuchnation is not, however, uniform, the 
 steepest part of it Iteing between the entrance of the River and the head of Grand 
 Island, embracing the Bridge site. The depth of the River between these two limits 
 is extremely irregular, varying from about eighteen feet to nearly forty-live. 
 
 The River bed is known to be solid rock above Stpiaw Island ; along side of 
 the Island it consists partly of rock and partly of clay, with a thin covering of gravel 
 above the clay. Below Squaw Island no examinations v,ore nuxde by the Bridge 
 Staff to discover the nature of the bottom, but it is well '-uiown to be of the same 
 irregular and composite character as above. 
 
 2 
 
12 
 
 Tlio banks of tli(> llWcv above tlio Falls arc low, cxcopt in front of Unff'alo on 
 tlic Aiinrican sido and near the Falls on the Canadian side. Tlioy rarely exceed 
 iifteen or twenty feet in lieij;ht, and are composed of clay, with occasional exposures 
 of rock. 
 
 It may be well lo explain that in front of linlfalo, and, in fact, all the way to 
 Tonawfrnda, tlu' east lianlc of tiie Erie Canal is considered to bo the east bank of 
 the Rivei', as tiie Canal is formed by takinj; in ov endosinji', part of the lliver, by 
 means of a mole or l)reakwater. J>y reason of the changes which were made when 
 forming the Canal, the west siile of Scpiaw Island, which is about a mile long, is 
 now the east si<le of the Jiiver, and that part of the Kiver which passed to the east 
 of Sqnaw Island is now lihuk IJock Harbour. Squaw Island is itself low, the greater 
 part of it being a marsh scarcely raised al)ove the usual surface of the Kiver, and 
 nearly wholly snbmeiged when the water is high. 
 
 During construction, tlio (U-pth of water, velocity of current, unequal foundations, 
 with the risks inseparable from the [»as.sing of rafts and vessels, were expected to bo 
 tho chief dilliculties to be encountered; while the greatest danger it was anticipated, 
 to which the Bridge, after it was built, would be exposed to, would bo from ico 
 fields which are carried down the River from the Lake. 
 
 The River never freezes all the way across, the rapidity of the current prevents 
 this ; but generally about the middle of Noveml)er the ico begins to form along 
 the shores of tho Lake, and a few cold nights are almost suflicient to fill tho Kiver 
 with small cakes broken off from the ico thus formed. 
 
 These cakes are worn by friction against each other till they are nearly round 
 and arc aliout a foot in diameter. If the weather remains cold, these pieces become 
 frozen together intt) hirge sheets, which continue to pass down the Kiver until the 
 ice " takes " or sets in tiie Ltike. The Kiver then becomes clear, and remains so 
 until perhaps about the end of February or beginning of March. Sometimes it is 
 free from ice until the end of March or Ijcgiiming of April ; this was the case in 
 1873. Occasionally, however, heavy runs occur early in the winter. The heaviest 
 happened during the first year tho Bridge was being built — it was on the first of 
 January, 1H71, — when tho ice came down in unbroken fields the full width of the 
 River, but not exceeding fourteen inches in thickness. None of the ico that winter 
 was as thick as that formeil during the two following ones, which were of almost 
 uuexanq)led severity. 
 
 The ice that comes down before March, unless the season is exceptionally cold, 
 is always extremely hard, and therefore much more likely to be dcsti-uctivc than 
 what passes towards Spring, which has been honeycombed by the sun and roiu. 
 
13 
 
 In tho wiiitors of 1871 2 ami lM72-n ico of imconimon tliiiknoss was formed, 
 and in tlio former winter fields of it—several times in tlio months of January and 
 February, (1S72)— broke off from the mass in tlie Lake, passing down tho full M'idtli 
 of the River, and from half a mile to a mile lonj?. Tiie thickness of these fields 
 was about three feet, and tlu' ico eompi-isini,' tliem extremely hard. 
 
 Ice runs of this kind i-ave an excellent i(h'a of llic forces aj-ainst which tho 
 piers would have to contend. 
 
 Generally the Kiver is i'vm from ico about the be>^innins f>'" middle of April, but 
 sometimes not until much later. In 1H71 tho last piece of ice disappeared on tho 
 11th of April; in 1>*7-' there was ice in the River on the :2:;nl of May, but for some 
 days previously there had not been (>nou,i,'h of it to retard or pi-event the movements 
 of barges; in 1S73 the ice remained until the 13th of May. 
 
 Almost invariably the Lake opposite liuffalo, and i'or miles westAvard up tho 
 Lake, is either frozen or Jammed full ol ice from the Anicrican to the C'ana<lian 
 shores; all the ice that goes down the River being formed ah)ng the shores and 
 at tho east end of Lake Erie. 
 
 Occasionally during tho winter large fields will break off and pass down the 
 River, os already .stated ; but if tho weather is steady and severe, the ice in tho Lake 
 will probably remain undisturbed until tho beginning of March, or even later. When 
 the ice is 1)reakiiig up, if the direction of the winds is continuously westerly, tho 
 only means of escape for the ico is down tho River ; the opening of navigation in such 
 a case is necessarily late, as many weeks are required to carry off tho large quantities 
 of ice accumulated at and near tho mouth of tho River. If, on the other hand, 
 easterly or north-easterly winds prevail in the spring, the ice is forced back into tho 
 Lake, and is dispersed sometimes in very few days. 
 
 Wlien high winds prevail in the months of January, February, and the 
 beginning of March, portions of ice are apt to be broken up and piled together in 
 large masses. The pieces composing these freeze together, and form homogeneous 
 masses called " clampers," which are often so thick that they ground in water twenty 
 and twenty-five feet deep. These "clampers," and the large ice fields which enter 
 the River from the Lake, would, it was confidently asserted by men who were supposed 
 to know the River well, endanger the piers. Some even went so far as to state most 
 positively that no pier could be built to resist them ; others took the ground that 
 tho design of tho piers was defective, and that the safety of tho Bridge could only 
 be insured by changing their form. 
 
 So widespread and so persistent were the clamours of these alarmists, that they 
 reached the ears of bondholders in England, who determined to send out Captivin 
 
14 
 
 Tylor, nil oiniuoiit Eiij,'lisli Fn,t,nnocr and Iiispoctor of Railwnys for tlio Board of 
 Trade in Britain, for the piirposo of report iiii,' upon tliis snl>jiHt. 
 
 He came out to Canada near tlu> ond of 1x71, and made a very earefiil insjjection 
 of the picra built the previous year; lio ol)tained, also from most trustworthy stuirces, 
 evidonco iu reference to the ice flows and other eharacteristies of the Niagara Uiver. 
 His own personal observations, with tiie information he obtained from others, 
 fully satisfied him that there were no grounds for alarm. lie therefore reported 
 as follows : — 
 
 " I have made particular inquiry into the thickness and force of the ico which 
 these piers will have to resist, and have visited numerous other structures exposed 
 to the action of ico under various circumstances, and I have come to the conclusion 
 that the cut waters of the three piers now erected are calculated, when shod with 
 iron, with the slope on which they are constructed of yi to t, to cut through and 
 to resist, without danger of failure, any i('(> which can come in contact with them." 
 Captain Tyler's opinion has proved to be perfectly correct, as the piers have since 
 then been expo.sed to the ice of two winters of almost unprecedented severity without 
 exliibiting any indication of failure. 
 
 Anyone Avho has been connected with engineering works of a novel character 
 and of considerable magnitu<le, will most likely concur in the statement, that there 
 will always be found in the vicinity of these works individuals who, instead of 
 drawing inferences from systematic and carefully taken observations, give full play 
 to a fertile imagination, and become " Prophets of evil ;" " Job's comforters ;" " Birds 
 of evil omen." 
 
 The International Bridge would have never been begun had a fraction of the 
 stories about terrible ice runs been credited. 
 
 A careful consideration of the subject having satisfied the projectors of the Bridge 
 of its feasibility, it became next a matter of some consequence to select the best site for it. 
 
 The location believed to combine the greatest number of advantages, and which 
 was therefore adopted, is about two thousand feet above the lower end of Squaw 
 Island. The width of the Niagara River at that point is about eighteen hundred 
 feet, of Squaw Island about thirteen hundred feet, and of Black Rock Harbour 
 four hundred and seven feet. By going further up the River— above Squaw Island — 
 a shorter crossing could have been obtained with a much less depth of water, but 
 this was more than counterbalanced by the di-sadvantages. First, of the greater 
 velocity of current, wliich would not only have added very much to the ditticulty 
 of building the piers, but would also have greatly increased the dangers to the passage 
 of rafts and navigation generally. 
 
 a.-^ 
 
15 
 
 Witli a normal cuiTciit of from xovpii to (Mf,'lit miles an hour, there would have 
 been gri-at risk in passing' vessels, and particulaiiy rafts, tlironyli the draw openings, 
 ns it is impossiltle to keep the loii},' rafts Htraif,dit that are rtin down the Niagara 
 lliver to Tonawanda, when they are in that portion of the Kiver between the Black 
 Rock and the entrance to the Kiver. 
 
 Second, of the bad anchoiaj;(' which extends all the way from Black Rock Ferry 
 to near the entrance to IJiiU'aio Ilarltoiir. In the event of a sailing vessel failing to 
 make the entrance to the Harbour, and turning within the influence of the current 
 iu the River, it could not be biougiit t(» anchor in time to avoid a collision with the 
 Bridge. 
 
 When the late Mr. A. M. Ross, the Engineer of the Victoria Bridge at Montreal, 
 propo.sed, in the early days of the IJuH'alo and Lake Huron Railway Company, to 
 locate the International Bridge near liie Hneiilo Waler Works, .so .sensil)Ui was he 
 of the dangers of vessels drifting against tiie slructure, that he suggested, as part 
 of his .scheme, that the entrance to liiill'alo Harbour siiould i)e nu)ved .sonu; distance 
 to the south of its present ]>ositi()n, .so that vessels entering it might not be exposed to 
 the danger of being drawn into the Niagara R'ver ; and he deemed this danger to 
 be of suflicient magnitude to justify the i)ridge Company in devoting part of their 
 capital towards making the contemplated change in the Harbour. A tliird objection 
 to a location above Stpiaw Island is the costFy approach on the east side of the 
 River, and the ditliculty of making Kjunections with the Railways terminating in 
 Buffalo. It would have been necessary either to tunnel under the city, or to have 
 made a deep and very long excavation through valuable property. In either case 
 the cost of this approach alone would probably have exceeded the whole expenditure 
 on the Bridge pro[)er. 
 
 The drawbacks to a location below .Squaw Island were, the gi'eat width "of the 
 River, the increased length of (loop line) Railway which would have to be constructed 
 to join the Bridge witii the (irand Trunk Railway, and the distance of the structure 
 from the City of Buffalo. The last objection might not have carried much weight, 
 had the Bridge been only intended to connect the American and Canadian lines of 
 Railways. 
 
 Another reason which had som<^ weight iu causing any location between Squaw 
 I.sland and Grand Island to be rejected was, that as the water was .shallow, there 
 would be considerable danger of the piers causing the ice to goige and form a dam 
 across the River. Although this consideration had its influence in determining the site 
 of the Bridge, sufficient imi)ortance was not i>robably attached to it at the time. 
 
1<I 
 
 Thcro t'nii l)o very littK' ddiiht iIimI ilic iliini,'i'r iipprolu'mli'd was noi jiii iinaijiimiy 
 one. Till' evil coiisi'tim'ncc.i ai'isiii;f t'luiii llu' plaiiiii; (if •'listriicliDiis in conipaiativcly 
 sliallow water in Uivcr.H which cairy down hir;;(' iMidics of ice, were strikingly exenijilitied 
 ill the ten'il)U' and disastrdiis ice j,""'rt" which was lorined in th(> Sns(|itchaiina River, 
 near its mouth, in tlie lii'ninninLj of lM'lini;iry, 1^71!. 'I'his aiciinuilation of ice was 
 caused by a nuinlter of piers, which were Imih near the liead of Watson's Island for 
 the purpose of intercepting; and K-ec|tin^ hack tinilicr. (Ireat risk was iiiirjuestionalily 
 avoided, and possibly jj;reat calamity averted, iiy locaiiiiii' the International Hrid<j;o in 
 deep water. That an ic<> i;-or;;e in (he NiM;.;ara Ifiver i-; hy no means an impossibility 
 was shewn a number of years an'o. when a dam was formed in the shallow water near 
 the mouth of the River. This dam kept back the water t'n\- .several hours, and lowered 
 the surface of the River so much that a lar^c part of the lied of the Rapids above 
 Niai^ara Falls was ilry, enablini;' people to walk out for a considerable distance from 
 the shores. So little watm- was there rmininj;' that timber lod^-cd afjainst tin; rocks 
 and wat! drawn ashore from near mid-channel above the Falls, a place which, in ordinary 
 stages of the water, is absolutely inaccessible. The considerations enumerated above 
 confined the choice of location within the narrow limits between the head and foot 
 «>f Squaw r.sland. l?elween theso |)oints lher(! could be no dillicultv in determining 
 the proper place for the lVid<;'e ; in fact, the advanta,;,'es possessed l>y the site .selected 
 were so obvious that they could .scarcely be overlooked. They were briefly these : 
 
 Fir.st. The River and Black Rock Harbour are narrower at the [)rosent site of the 
 Bridge than they are anywhere else l)etween the up[)er and lower ends of S(piaw Island. 
 
 Second. The water being deep, the current is less rapid. The great depth of water, 
 taken per se, is certainly objectionable, bat it is less so than a violent current. 
 
 Third. The depth of water is so great, that it is confidently believed no danger 
 exists of the ice gorging all the way across the Kiver. 
 
 Fourth. The bottom of the River atl'ords good holding ground for anchor-; for 
 more than half a mile above the Bridge, so that in the event of an accident to a 
 vessel it can, in all probability, be brought safely to anchor before reaching the Bridge. 
 
 Fifth. The approach upon the Canaila side of the River is good, that upon the 
 American shore is not only an excellent one from an engineering point of view, but 
 ■ ; a favourable one, in so far that it destroys very little valuable property, and can 
 easily be connectcil with the Railway lines terminating in Buffalo. 
 
 In locating the Briilge the interests of navigation were ke})t in view ; but so far 
 as they were concerned, it made very little difference wlu'ie the Bridge was built .so 
 long as it was kept out of the swift current above Black Rock Ferry. The Bridge 
 wherever placed must interfere to some extent with navigation, and it was simply 
 
17 
 
 iibsmd to cry <uit, us many did, that tliu ri^lits of Hliipownors nuint not bo tronchod 
 upon in tiif snialliMt dc'^riH'. 'I'liu cic'C'tloii of a BridH;() acroHs a navigable stream ia 
 always to bo dopiocatcd if tliciv bi- any ivasiniablo way of avoiding; it. But if the 
 comnieivial interests wliiuh arc lobe served by a 15ridj,'e are j,'reatei' tlmn those which 
 are alleeted iujurlDUsly by its ereetion, there ean be no fiuesliou that the hitter must to 
 some extent j,'ive way. 
 
 In the ease of the International Drid^e, there eamiot be a question as to the 
 superior importance and vaUu; of tiie interests to be served by it, as compared with 
 those of the navigation on the Nia^^ara Kiver. 
 
 Althon^ii the <;r'>ii»tl t'» ''i' traversed liy tiie lines of IJailway connecting the 
 International ISridj^e and the llrand Trunk Haihvay on the Canadian side of the River, 
 and the New Y'ork Central itailway on the American side, had not actually been 
 surveyed previously to the site of the J5ridge being chosen, a reconnahsance had been 
 made of it, from which it was known that there would be no diillculties whatever of 
 an engineering character in forming the connections. VV'lien the connecting lines were 
 located, the length of Railway re(|uired to join the Bridge and the Grand Trunk 
 Railway was found to bo 'M^ miles. 
 
 This line was a favourable one, with a good approach to the Bridge, on a tangent 
 with an inclination towards tho River of only 15 feet per mile. On the American side 
 two connections wore needed with tho New York Central Railway ; the aggi'egate 
 length of these was nearly half a mile. One of them was to join with tho New York 
 Central Junction Railway, running round the City of Buffiilo and into tho Station on 
 Exchange Street. The other was to connect with the Niagara Falls Branch of the 
 New York Central Railway, terminating at tho Erie Street Station. 
 
 The line across Sipiaw Island, connecting the Bridge across the River with the 
 Bridge over Black Rock Harbour, was on a curve described with a radius of 1,910 feet. 
 Tho distance between the Bridges measured on this curve was 1,106 feet. 
 
 In addition to the connections with the Ciraud Trunk and New York Central 
 Railways, for which provision was made by the International Bridge Company, junctions 
 wore formed with other Railways built since the Bridge works were begun. On the 
 Canadian side of tho River two new Railways were run directly to tho Bridge, and 
 are now finished, — tho Great Western Air Lino from Glencoe, the Canada Southern 
 Railway from i\.mherstl)urg on the Detroit River and Courtwright on the St. Clair 
 River. Both of these lines are first class roads, Iniilt with easy curves and low gradients, , 
 intended for American through travel princii)ally, and will therefore brhig a vast I 
 accession of business to the Bridge. 
 
t8 
 
 On the Anipricau side of tho River tin* New York. West Shore an<I Chicago 
 Railway has been located, and is partly luiill. 
 
 Tho alignment and gradients of this liuihvay are snch as to warrant the expectation 
 that it will rank, when completeil, with the best roads on tlie Continent, and tliat it 
 will do its full share towards preventing any Mock, at ibitlalo, of easlwanl l)onnd 
 traffic brought over the Bridge by the roads t)n the Canada side. After the choice 
 of location was made, steps were taken to ascertain the direction a . velocity of the 
 current, so that the piers miglit be built exactly in \hu- with it. As no vessels 
 navigating the Niagara Kiver draw more than li' feet of watci', it was considered 
 that information upon the direction and velocity of the current down to this dei)tli 
 would be all that was necessary. 
 
 The method pursued to ascertain this was so simple, and at the same time 
 answered the purpose so well, tliat it is considered worth while to give a detailed 
 description of it. Although the primary object in view was to obtain the direction 
 of the stream, the same operation determined accurately its velocity. Tho application 
 of the method to ascertain the velocities, i&c, at the Iniernational Bridge, was proposed 
 by a Board of Military Engineers, who were appointeil to examine and report upon 
 tho Bridge site and plans by the United States Secretary of War. 
 
 The method was briefly as follows :— A base lino 1,021 feet long, extending from 
 a point 169 feet above tho Bridge, was measured on the west bank of the River. 
 At each end of this base line a theodolite was placed, and two observers were stationed, 
 one to use the instrument, the other to mark time and give signals. At intervals of 
 half a minute of time tho angles contained by the l)asc line, and by lines drawn from 
 each end of it to a float in tho River, wore read simultaneously. 
 
 It will be apparent that the jiosilions of the floats laktMi in this way at the end 
 of each half minute, will not only indicate the direclion of the space traversed by the 
 float in the time but will also give its exact length, froni which tiie velocity of tho 
 current in miles per hour may be deduced. To distribute tlic floats a small Tug was 
 used. The Tug went some distance above tho upper end of tlie base line, and when 
 throwing a float overboard wliistled to call the attention of those stationed at the 
 instruments at each end of tlie base line, who continued to take the sinndtaneons 
 observations upon it until the float had passed below the lines of the Ibidge. (.)l)ser- 
 vations in eleven lines were taken in this way. These lines were intended to be 
 equidistant, but it was clearly impossible to make them so without detcriiiining 
 trigonometrically, or by .some other equally troublesome mode, the position of the Tug 
 before throwing out each float, This was not t:onsidere<l of suHicient inq)ortance to 
 justify the trouble and loss of time. An assistant on the Tug estimated as nearly as 
 
lU 
 
 practicaMo the propor distaiu't's from the shoi-c nt which the floats were to bo thrown 
 ill. The floats wore pino sc'aiitliii<,'.s three iiithoa by four inches, and were twelve feet 
 lon<; ; each was loaded at one end, so that when put into the water it would float 
 in a vertical position, and would show the other end just above the water. To enable 
 tiio observers on shore to follow tlicse floats easily with their eye, a small staff about 
 eighteen inches lont,', with a red flag attached, was iuserteil into the top of each float. 
 No dilficulty was experienced in taking the observations, as it was found that an angle 
 could be read anil recorded in flfteen seconds, which allowed an equal time for turning 
 the limbs of the instruments and for bringing the cross hairs of the telescopes on 
 to the red flag on the float again. 
 
 The positions of the floats at the end of each half minute, taken in the manner 
 above described, were i)latted to a very large scale, and the direction and velocity 
 of the current in each line were obtained graphically. Figure 3 on jilato No. Ill 
 shews this diagram drawn to a reduced scale. 
 
 No real dilliculty Avas involved in the taking of the velocities and directions of 
 current as above described, nothing more being recpiired when doing the work than 
 constant attention ; but the next operation to be described, that of taking soimdings, 
 was oni! of the most troublesome connected with the Bridge siirvey. The first 
 attempt made in a small boat, proved to lie a fiiilure. The i.ext p'an tried was to 
 anchor a Tug over the site of each pier and sound all round it from the deck. This 
 was oidy partially successful, as, by reason of the swiftness of the current, the lead was 
 carried a long way down the Kiver l)efore it touched the bottom, and the depths 
 ol)tained in this way wore consequently too great, as the figures on the lead lino 
 represented the hyi)othenuse of a right-angled triangle instead of the perpendicular. 
 
 The next plan followed was to erect on a scow a framework to carry an iron 
 rod one incli and a (juarter diameter, working vertically through guide rings. It was 
 thought that the rod if allowed to fall suddenly would reach the bottom without being 
 deflecteil from an upright position : but even this did not ansAver, as upon the first 
 trial the current bent the rod so nnich that it could not bo used again. The method 
 finally adopted, and which succeeded perfectly, was to anchor a large bargo or scow 
 so that the centre line of tiio Bridge passed over it at midships. Across the bargo 
 tind)ers ten feet apart were laid, with their ends projecting twenty feet beyond one 
 side of it. The barge was then placed and retained in such a position, by means of 
 a side anchor, that the projecting ends of the cross timbers were on a line nine and 
 a half feet beyond tho outside of the ground the pier would cover. When the bargo 
 had been properly placed, .i Tug, kei)t in attendance during tho whole time tho soundings 
 were being taken, towed a yawl with a suitable crew throo or four hundred feet abovo 
 
20 
 
 the barjjc. Tlic yawl was tlicii cut adrit't iiiul ullowi'd to Hoat ilowu the JiMvt-r, ln'iiii; 
 steered so us to pass i-xactly uinlor the cinls nl ilic jirojcctinu tinilicrs. So soon as 
 the yawl was detached Irom the Tnj;, tlio iicrsoii whose duty it was to lake th(> soundings 
 threw the lead overboard and aHowcd it to remain susjiended troiu tlie Ixiat and at a 
 distance of one or two feet from the liottoni of the River. 
 
 It will be seen that hy allowing; the lead to hauy in tliis way finm a lioat which 
 was driftinj; down the stream it would iiauji' iJerpeiidicularly under tlie boat, as botli 
 it and the boat would have the same velocity the velocity of the current. The water 
 wouhl eertainly move with .Munewhat less rapidity near the bottom of the Jviver than 
 at the surface, but the weij,dit of the leail was in all cases snilicieut to overcome the 
 difference, and to maintain the lead line in as nearly as possible a vertical position. 
 As the yawl drifted nmler the end of the lirst timber the man with the lead dropped 
 it the required distance, one or two b-et as the case mi^ht be, toucheil bottom and 
 called out the readinj;, which was recorded by an assistant ui>on a diagram pre\ iously 
 lu-epared. I'robably before the man with the lead line cmdil recover himself and be 
 ready for another soundin;;, the boat had drifted un<ler say the last ti.nber, when he 
 Jigain took the depth. The Tuj,' was always in reailiuess to tow the yawl after juissinj;: 
 the barge up the Kiver aj;aiu. l>y repeatinj;- the operation described ab(»ve. perhaps 
 three or four tinies in each line, a sounding' was obtained under the end of each timber. 
 When the .soundings on one line were finished the barge was moved nine and a half 
 feet over, and soundings again taken in the .saiue way as liefore. and >;o on until five 
 lines were gone over, covering a si)ace of eighty icet long by thirly-iight IihI wiile. 
 The scour for every lino of soundings was accurately placeit in accordance with signals 
 given from the en<l of a base line on the I'anatia .shore, by an ob.ser\i'r with a ihcodulile. 
 The .soundings taken in the way describeil proved to be n'markably coirect. and at 
 no time during the progress of the works was any trouble i-xpiMii-nci'd or txpen.si' 
 incun'ed in eon.sequenco of any error in them. 
 
 Tlio depths of water in which the piers wotdd have to be built was found to ho 
 least at No. 8, where it was only about seven feet, and to be greatest at Nd. ."•, where 
 it was found to bo forty-three feet ; this last depth was afterwards increa.sed .several 
 feet by the removal of gi-avel from the site of the pier. 
 
 The velocities of the cmrent and the .soumlings thus obtained, together with the 
 width of the River, afforded sullicient data for arriving at a moderately dose approxi- 
 mation to the (piantity of watir discharged by the Niagara Ui\er in its normal slat<'. 
 
 The area of the section of the Hiver at the Ihidge site was in round numbers 
 as nearly as po.ssible 41,0(t(t .s(pnire feet, and the average veliuity of the water per 
 second six feet. The discharge therefore woidd be :i4ti,(*(K> cubic icct per second, 
 or say 1,535,040 imperial gallons. 
 
T\w iliscliiir.nc, Imwcvcr, riv(|iioiiily (liH'cinl iii;iti>riiilly from this, the variations being 
 ranscd liy tlic Huctiialinns in tiii' ii(-i,i,'hr of the .sinraco of the Kivcr produced by winds 
 and iec. A record of tlic-^c Huctiiations was liept daily from the 1st of Anj,'ust, 1S7(», 
 to ihc Isi of Aii-ii>l, H7;:. Till' ilianrani coinpiled from these daily oliservations and 
 shcwni.n the rise .nul fill of tlii" water, is siiewn by l'"i,L;iires 1 and 2 on Plate 111 
 in icference to tile low water liiu' siiewn on the water f^'nay-e, it may not be umiss to 
 state thai it was established from the evideiu'e of iiitelli^'cnt, trustworthy witnesses 
 who had resided (or many years in the vicinity of the i;ridj,'e site. It was important 
 to determine this with a near ajjiiroacii to aecuracy, as, in aeeordance with the terms 
 of the r.iidyc Charter, theiv had to be a clear liei,y:ht of -JO feet fnmi low water level 
 to the under side of the I'.ridnv snpei'strueture. It was satisfactory to find before 
 t!ie Ihid-e wa-; finislie.l that in this matter tlie le-al re(iuirements liad been liberally 
 comiilied with, as fiv(iiieiitly dmin- the pro-irss of the work tlie Kiver fell C(msiderably 
 
 lielow the assni I low water line. Tlii' hei.-ht of low water was taken as datum 
 
 and was ealled lud ; all siilisei|ueir. levels were referred to this datum. Inconsequence 
 of the liiver never freezing all tile way aero.ss, it was impos.sible to .set out the position 
 of the i)iers by measurinj,' the distances between them on the ice, as was done at 
 the Victoria 15rid;,'e at Montreal, neither eould the intervals between the jjiers bo 
 obtained, as is freqiu^ntly done in similar works, by measurin.i,' alon^i; the falso works 
 used in the erection of the permanent portions of the structure, as no fixed staging 
 eonld be hnilt in the Ifiver I)y reason of the great dei>tli and velocity of the water. 
 
 for the reasons given above it was decided, at the very begimiing of the work, 
 that every piece of masonry should be set out trigonometrically. For this jjurpose 
 a base line l,7>^!t,' feet long was measured on the Canada .shore, and extended in a 
 southerly direction from the centre line of the l?ridge produced in a westerly direction. 
 
 The angle contained by (he centre liiu> of the IJridge and the base line M'as not 
 .so well conditioned as was desirable, being !»2 :51' on the side of the ba.se line next 
 to the Kiver. IJiit as tlio instrument used in determining the positions of the different 
 points for the .structure was a remarkably good one, the fact of the angles being a 
 litth- too large <iid not make so nuich difference as it woidd have done had the in.strument 
 lieen one of only oriliiiary character and small size. iJiit for the purpose of guarding, 
 as far as possible, against any errors creeping into the work, a verification base Mas 
 laid out on Squaw Island, and th(> po.sition of every point was determined from one 
 base line and verified from the other. The lengths of the base lines were established 
 by measuring the exact distances between the ceutr(> of sipuire headed stakes, driven 
 at short intervals and accurately rangeil into line with the theodolite. The relative 
 elevations of the tops of the stakes were then carefully takcMi with a level, and by 
 <alculation the true hori/imtal distances between them obtained. Each base line was 
 nu-asured carefully in the first place with a properly adjusted 1(10 feet chain, for the 
 
purpose of obtaining its length approximati'ly ; the lougtli of I'ach was tliou rc-ninisiirccl 
 as accurately as practicable with a C'hestennan steel tape, which hail previously been 
 compared with the -itandard measures sujiplied l)y the riKcnixvilh* Iron ('()nfi)any, 
 who wcro to manufacture the superstructure. 
 
 Tho base line on the Canada shore was checked a second tinu> with the steel 
 tape, prior to any work being set out froni it. ^Vl'ter the lengths of both Ijaso lines 
 had been determined, they were coiuiected by •rianguhition, and the length of the ba.so 
 on Squaw Island calculated from that on tiie Canada shore. The result was most 
 gratifying, and gave that degree of confidence in (he measurements without which tho 
 work could not have been carried on with any satisfaction. 
 
 After verifying the base lines, the next step was to ealculate the angles contained 
 by them, and the lines drawn from their southern ends to the centre points of the 
 piers on the axis of the Bridge, and to the points formed by the intersection of thi.s 
 axis with the lines of the points of the abutment at Jhidge seat level. These angles 
 were all worked out to seconds, as tho instrumeut u-sed in setting them off was divided 
 to ten seconds, and could bo read by estimation to five seconds. 
 
 On the Canadian side of the Eiver a small wooden buihling w.as erected on tho 
 highest ground near the end of tho Bridge, but west of the base line, to contain tho 
 instrument to be used in " keeping up " the centre lino of tho Bridge across the Ilivcr. 
 This instrument was permanently placed on a stone pedestal exactly over the centre 
 lino of the Bridge. Tho other end of the centre lino was defmed by a square cedar 
 post placed firmly in the ground about 1,^00 feet Ijcyond the east end of the IJriilge. 
 
 This post was painted Avhite with a black stripe about two inches wide drawn 
 vertically down tho side facing tho west. No trouble was at any time expei'ienced in 
 seeing this stripe through the large instrument set on masoniy west of the Bridge, and 
 there was consequently no dilliculty upon any occasion in ranging the caissons, piers, &c., 
 into line with the axis of the Bridge. 
 
 The above description of the preliminary arranginu*nts for setting out the works 
 refers wholly to tho Bridge across the Niagara liiver. For the Biidge over Black llock 
 Harbour exactly the same course was followed, excepting that the base lines were not 
 quite so long, and that the centre lino or axis of the Bridge? was not defined by an 
 instrument set in masonry at one end of the line and by a s(piared post at tho other. 
 This line was established by a stout stake driven level with the gi'ountl near the Niagara 
 Street, with a nail in the centre over which a theodolito couhl be set, and by another 
 stake driven on the top of tho west bank of tho Niagara Kiver exactly in tho centre 
 line produced. 
 
 An account of the details of the i)lan pur.sued in giving the position of the caissons 
 and piers will not be inserted here, as it can perhaps l)e more conveniently introduced 
 when describing the foundation, works, and masonry. 
 
CHAPTER III. 
 
 PROGRESS OF THE WOKK-DIRECTORATE AND STAl'F EMn.OYF.D. 
 
 AVliou the constnictioii of tlui r)ri(lj,'o Avas l)i'j,'un in the early jiart of 1870, it ^vas 
 dctcrminiHl to coinmcnco witli Pier No. 1, next tho Canadian shore, and to build 
 regularly towards tlie east, postponing the erection of tho west (Canada shore) abutment 
 till tho winter, when operations in tho River were impracticable. In piu'suanco of this 
 plan Piers Nos. 1, '2 and ;i, innnbering from the west or Canada .shore, were built during 
 tho first season ; Pier Xo. U was finished on the L';5rd D(>cemb(>r. Taking into account 
 that the fust caisson was not launched until tho l:]th July, — that everything connected 
 with the works in the way of plant had to bo provided, and a system of operations 
 had to be inaugiuatcMl and organized involving many points of great uncertainty and 
 dilliculty, — fair progress was made during the fust season. In the month of 
 January, 1871, tho west abutment was begun, and was finished in tlie month of April 
 following. With the opening of tho .spring of t>^71, vig(jrous mea.sures were taken 
 to cany out the in'ogramine drawn up at the conunencement of the work. A 
 cais.son was launch(>d for Pier Xo. 4 in .September, ls7(l, and an elVort was maile to 
 sink it in May, ls71,bnt for reasons, which will be detailed in a subseiiuent chapter, 
 it did not prove successful. It was not considered ad\isable to make any fu.rther 
 attempt to erect this pier that vi'ar, Imt to go on with X^o. .">, for which a cai.sson 
 was launciied in May. In duly it was ready lor sinking, but the same untoward 
 accidents t)ccurred when trying to jyut tlie (nie for Xo. .'> into position which 
 prevented the placing of Caisson Xo. 4. 
 
 J3y this time tho season was so far advanced that all idea of (loing anything 
 moro in tho river until the following year had to be abandoned, .\lthough it was 
 impracticable to carry on masonry in the liiver until ls7i'. there were no reasons 
 why the abutment in the east sidi" of the Iliver on Stiuaw Lsland, and the Bridge 
 <tver I'dack Ivock Harbour, should not be proceeded with. ^Measures were therefore 
 taken to go on with these works at oiue. The tii'st pile for tho east abutment of 
 the Black IJock Harbour Bridge (known as Abutment X"o. 4) was driven on tho 28th 
 July, for Abutment No. ;» on the I'nd August, for Pier No. [) — tho pivot pier— on the 
 Kith August, for Pier Xo. Id on the 'J8th August, and for Abutment No. 2— the east 
 abutment of the main Bridge— on the 14th September. A glance at these dates will 
 show tho determination to proceed with tho works mo.st energetically, and affords 
 convincing eviilence that the unsuccessful attempts to found Piers Xos. 4 and o had 
 not a chilling or depressing effect upon tho prosecution of the enterprise, and that 
 
124 
 
 no (loiihts wore ontortaiiicd ol' iiiuIiiiL;- a way to sociiiv sutliriciit Ibundations fur 
 tlic deep water piors. 
 
 In tlio oaily jiarl nC Anynst tlic niasmirv t'nr Aluilnu'nt No. 4 was lu-^nn. ami 
 was iinisluul tor tlic reception of llic iron ^\(.ri< caily in tlii- autiuiui. AlMUnicnt No. ',', 
 was l)i\2;ini in Septonil)or and iinislicd in Octnlicr, 1^71. Tlic masonry of Pier No. ](» 
 was built durinj,' the months of Octobor ami XovcndicM-, wliilc the first stone of Pier 
 No. 0, or the pivot pier, was laid on tlie :!nl Novt'mber, 1^71, ami tlie last on the 
 2Sth starch, lS7i'. 
 
 Xothin^f was done to -Vbutmeiit Xo. •_', nu Sipiaw Island, duriiijj; 1S71. exeei)t 
 driving- the piles and jinttin^' on the limbci' platform for the foundation, .so as to 
 insure an early start in 1S7l'. 'I'lu' masonry of this abutment was be^nn on the 
 IJOth Manh, and completed on the 1st .Iinic followiiii,'. It was fortunate that the 
 foundation of this abutment had lieen pi'cpareil in the previous autnnni, so as to enable 
 a beLiinniny to be made early in ihe season, as worl; in the River was retarded by 
 the unusually late perioil at which the last of the ice pas.sed down the itivcr ; it was 
 as lati> as the l'3r(I May before it had wholly disa|)peared. As soon as jn'acticable 
 the bnildin,y of Pier No. s was connnenccil. and it was completed in July. Pier 
 Xo. 7 \Nas iinished about the end of Ani^ust. Pier Xo. (» on tlu" i(tli X'oveniber, and 
 the last stone of Pier Xo. .') was laid on llu' I7th December. This tinishod buildinir 
 operations for the year 1^7-. 
 
 In addition to the stone piers biult during- this season a wooden rest pier for tlio 
 upj)er end of the main draw girder was ercctc(l. .\t the clo.-c of li^72, as will bo 
 <,'athercil from the prccedinj; account, the only pier remaining.,' to bo built wa.s No. 4. 
 The caisson tor tliis jiier was placed in position on the 7th -Tidy, lS7i), and the la.st 
 stone of the i)ier ami of the P>ridge was laid on tlie 4lli (Jctober, 1873. 
 
 Although duriii;;- the buildini;' season of 1s71 no masonry was laid in the Niajjara 
 River, the iron .suiierstruitnre over tiiree spans, lictwcen Nos. 1, "2 and 3, was finished 
 by the 1st October. In February of the fnllowiii,;- year, 1S7:>, the suporstructuro of 
 the Ijrid^e over JJIack Uock Ilarliour was <ommenccd. and iini.shed early the 
 following,' .lune. 
 
 In duly and .\u,<.;ust Span Xo. '.t of the Main llridge was erected, and tho River 
 draw j^drder was swuiii;' for the first time on the :!rd danuary, ls73. Durin<,' the 
 summer of 1s7;j Spai>s No. f>, 4 and .") were erected in the order in which they are 
 named, the last meiitioiu'd .span beini;- lowcreil on to the masmn-y on the 'J3rd 
 October, 1X73. 
 
 Durintr the winter of ]s71-l* the piles for the trestle work, s])oken <if in 
 (.'liapter Xo. 1, extending' across Sipiaw Island and conm-ctiiij;' the tivo Uridges, were 
 driven, I'Ut the trestle work was not v.liolly completed until the summer of ls73. 
 
 The first locomotive crossed lilack Rock Uridgc! on the 24th -Inly, 1h73, and 
 the P.ridne across the Niai^ara River on the L'7th October followinj.(. 
 
l)ri;i:(T()I{.\T!.; of TlfK IXTElfXATIOX \l, r.IMDr.K compaw 
 
 M'AI'F KMl'l.OVKI) I\ Tin; CONSTiaCTIOX OF Till; I'.KIIHiK. 
 
 I \'r i; i; \ AT ION A I. is i; i im: k fo.Mi'AW. 
 ■Dircdorii. 
 
 C. .1. lillVDiiKS, I',-:,;.!,,,!. 
 
 HON. i:. (;. spAi-|,uiN(;, v;n i'nM,:„i. 
 
 HON. .lAMKS FKIMIIKK. 
 JOHN r.KI.I.. (,M'. 
 
 A. AVAl.Sll. 
 i;. I'. S1M!A<;1K. 
 
 ]'. i:. .iAi;vi>. 
 
 .)(».<i:i'H HK KSUN, ,v,ov/,„-y»„,/ 7V..r„',,/. - - - K. »'. SI'KAdli;, ,nW,V,V.„-. 
 K. P. HANNArolHi. C K., .M.A.. I.i;c r/,/./' A',,;,/,,.,/. 
 
 josKPii uoKsoN /:.;■'■■„( /:,„,;,„. ,■. 
 
 J. f!. MACKI.IN i..,;,/„„< ;;,,,/,•„../. 
 
 wi r.KJiion r.A i i.i: y j,.;./,/»< /■:„,,; i,--,,- ,i,„i D,;c',//,i^man. 
 
 \v. .). (;l"yi,ki: j„.y,..t,„- „/ .'./„..„i,n/. 
 
 • iKolior. Hl'OHK.S /.,yrlw<.r/,;.u UWL 
 
 (Chief Contractors.. 
 
 C. S. OZOWSKI, CIO. - . - Hon. U. I,. .M.\(lMlF.l:soN. 
 
 S^taff of Chief Contraitorci. 
 A. \v. scHWiFOKi; {.J, It owl (;r„-,-f '.•-,>/,■,■;, It,,,./, „t. 
 
 V. M. (iZOWSKl, Jmir <'<i-t/iier antl Aecuitulnuf. 
 
 T. ('. SCOliLK AsiiiiitaHl Kinjineft: 
 
 (!KOR(!|.; UOP.INSON AsHUlmil KwjMfn: 
 
 OrrO MKYKll In e/i'f,-'j" of A.irlwr'mii. S'nikht'j ]'i>,i/no„,i „iul Divh/iuy. 
 
 JA.MK.S ll.MKlAitT Cii/ilniii in. c/iuiye nf Ti"js, S-oir-i, ,( ,■. 
 
 S. K. CITFITIS ('iij,i,n,i. of Tmj "Juli-riinliuiio/." 
 
 WK15STKU COLLINS /„ c/,u,yc of the Dvcd.jc. 
 
 FUANK DAVIS />;,vr. 
 
 JOSKPH i;oi;rUKU Dicer. 
 
 J. AlnPvRISON- CoHtnwtor for Jfamnr;/ for Cl,i,f Conlrnetors. 
 
 IIKNRY .MAd'AKLANK Cnlmrttir fi^r ('(iuj<.„m ,i,nl Titnhrr Wurk 'j, luinlh/ " 
 
 J. K. liACJLliiY Contractor for Jirectiiiy Iron Work " 
 
CIIArTER lY. 
 
 I'OlXnATlONS AM) SlT.AylT.OlS WOUK. 
 
 Surveys ami cxaininations, Mitli tlic soiiniliiij,^s that won' taken, l)rou<?lit to lij,'ht 
 the fact that for a distanco of ovor (!(((> feet from the Canada shore the bed of 
 tho River consisted of rock ahnost smooth, and that for about 700 feet from Squaw 
 Island tho bottom was composed of strong chiy covered with gra\'el. Kespecting tlio 
 intervening 500 feet in tho middK; of tlie Eiver, the same trustworthy information 
 couhl not bo ol)taincd, but tho conchision arrived at after the most searching 
 investigation, under very adverse conditions, Avas that tlio bottom was rock. 
 
 A good deal of dilliculty was experienced in conducting this investigation. 
 Borings could not be made without incurring expense and loss of time that would 
 go a long way towards building tho piers. To explore the 1)ottom of the l\iver 
 flowing at tho rate of nearly six miles an liour, by divers, at a depth of over 40 
 feet, was (piito out of the question. 
 
 TIio conclusion, therefore, after making tlio examination and obtaining the most 
 reliable evidence, was that Piers 1, l', V>, 4 and 5 could be l)uilt upon rock without 
 removal of gravel or any other material beyond perhaps some few boulders or loose 
 pieces of rock. 
 
 Having •arrived at that decision, the liest course; to adoi)t in putting in tho 
 foundations had next to be considered. Ordinary cofler-dams, in ileep water flowing 
 with a high velocity over rock bottom, could not l>o used. Otiier methods were 
 proposed and discussed, and the plan ultimately determined upon for I'iers 1, 2, ',i, 4 
 and 5 was a water-tight floating caisson, to be sunk directly on the rock where it 
 was not covered by a deposit. 
 
 For River Piers Nos. 0, 7 and 8, and for those in IJlaek ]{ock Harbour (known 
 as Piers Nos. 9 and 10), under all of which there was a great de]ith of clay, it 
 was decided to drive ,'i)iles ; to cut them off at a uniform level as closely as po.ssiblo 
 to tho bottom, and sink upon them water-tight caissons similar to those sunk upon 
 tho rock ; round the piles heavy " riprap " to l)o thrown to avert the danger of 
 scour. Neither of these plans was new, and therefore not cxperinunital ; the hitter 
 has been used in many instances, tho former had almost fallen into desuetude. 
 
 Mr. Mylne, in building JJlackfriars ]5ridg(! over the River Thames in London, 
 and Mr. Labelye, in constructing Westminster Bridge over the same River, employed 
 
27 
 
 water-tifflit caissons sunk on tlie bed of the River; but at Westminster Bridge the 
 bottom was clay, and the plan did not provo (luito successful, owing to the scour 
 which took place under sonic of the caissons, although pits had been dredged for 
 their reception. This mode consequently became discredited to [a certain extent; 
 but the fact of an injudicious application of it having resulted in partial failure was 
 no reason for rejecting it where it could bo employed under more favourable conditions. 
 
 There are many examples of foundations formed by piling for the reception of a 
 water-tight caisson. .Vmong tiiem may be mentioue<l the Kong Bridge at Plymouth, 
 England, and a very line lailway bridge over the Meuso at Liege, France. 
 
 No professional engineer or practical bridge builder familiar with subaqueous 
 foniulations would consider them ilefective or objectionable on account of timber 
 entering partly into their composition. But as, during the progress of the International 
 Bridge Works, (piestions have fro(piently been asked whether it was not a source of 
 weakness in the first ])Iaee, and of serious danger ultimately to the stability of the 
 structure, to use timl)ers in foundations, it may l)o stated that timber immersed ia 
 fresh water is not subject to decay. Wood that has for hundreds of years been 
 buried in sonie of the ))ogs of Ireland has Iteen tnken up in a perfectly sound state. 
 
 Piles driven by the Romans for foundations of some of their bridges nearly 
 1800 years ago are still quite sound. A remarkable confirmation of the assertion 
 that tindjer is imi)erishable from decay under water is also to be found in the 
 remains of Trajan's Itridgo across the Danid)e, near Tchcrnetz in Turkey, where the 
 exterior of many of the piles has become petrified, while the interior is as sound as 
 on the day they were driven. 
 
 The plans devised, as already explained in general terms, for the foundations of 
 piers were believed to meet all the reiiuirements of the case ; but experience, gained 
 in attempting to jilace cai.sson.'^ Xos. 4 and '», revealed that the bottom of the River 
 where they were to stand, instead of being smooth rock as was supposed, consisted 
 of large boulders intermixed and packed with gravel. The removal of this material 
 overlying the rock was considered absolutely necessary, and led to changes in the 
 plan of foundations for Piers Xos. 4, 5 and 0, for which it was found necessary to 
 modify an<l extend the original plan of caissons. 
 
 Several plans were proposed and carefully considered. At length it was 
 determined to construct large bottomless caissons of wood to enclose a space 
 somewhat larger than that occupied by one of the ordinary water-tight caissons 
 used for Piers Nos. 1, 2 and 3. The object in enclosing this space was to obtain 
 an area of still water in which divers could work, and to admit of vertical dredges 
 being en;ployed for the removal of the dejjosit from the surface of the rock. 
 
28 
 
 The bottom of the large caisson to liavo woilgo-shapcil cutting edges, so that 
 as tbo gravel was removed from its interior l)y ilrodging, tlio caisson would settle 
 down vertically. When the rock was made bare within the c-aisson, level it, if 
 necessary, and then sink on it an ordinary Avatcr-tight caisson. 
 
 The plan of cais.sons having been described in general terms, a detailed account 
 may now be given of their form, construction, methods of anchoring and sinking. 
 
 PIER No. 1. 
 
 The soundings taken for this pier .showed a deptli of water on the west side 
 of the site 9 feet, and on the east side 10 feet. In the direction of the stream tho 
 water was uniform in depth. Tlio rock, althougli sloping to the east, Avas found to 
 bo free from twist or "Avinding," and no dilliculty therefore existed in the way of 
 framing a caisson to fit it. 
 
 This caisson was built of sawn pine timber 12 inches square, anil was rectangular 
 at tho stern and pointed at the bow ; its length from tho stem to tho shoulder at 
 the back of the bow was 47^ feet, its Avidth 10 feet, and its length over all, from 
 stem to stem 55 feet. The sides and ends were perpendicular. At tho angles tho 
 timbers were halved and bolted together. All tho timbersj both in tho bottom and 
 sides, were bolted together with | inch square iron rag bolts, 2 feet 9 inches long, 
 driven in each course 6 feet apart, each bolt being long enough to pass through 
 two timbers and 9 inches into tho third. Each pair of timbers was in reality 
 bolted together every tAVO feet. Tho caisson was built up to a height of 9 feet in 
 this way ; it was then sheeted all round the outside with 3-inch pine planking 
 securely spiked to its sides, and tho bottom Avas covered on the insido in tho same 
 manner with planking of a like thickness. Tho joints of these planks Avero thoroughly 
 caulked and pitched, so as to render them Avater-tight. 
 
 If built only 9 feet high, tho caisson, when simk to tho rock, Avould havo been 
 wholly under water. To raise it above tho level of any ordinary flood in tho River, 
 4 feet in height was required to bo added to the portion already built; but as it Avas 
 intended when the pier Avas finished to remove tho upper four feet, and to leave 
 only tho bottom section in the AA'ater, it was necessary to build it separately, for 
 the sake of taking off tho upper portion of the caisson, and afterwards to connect 
 it by long screw bolts passing through tho side and end timbers of the top part, 
 as well as through the upper timber of tho lower portion, under which (upper timber) 
 nuts were placed to receive the ends of the rods. 
 
Tho method of connoctiii},' tlio two sections will be more easily understood by 
 referring to Plato No. V. As soon as tlio two portions of tho caisson were firmly 
 connected by those bolts, tho scam between them was caulked, and tho upper part 
 was planked and caulked in tho same way as tho lower part had been. 
 
 Tho general fonn of all the water-tight caissons is shown on Plate No. V. 
 For Nos. 1, 2 and 3 only one thickness of 12-inch timber was used for tho bottom> 
 and in every instance tho amoimt of internal bracing was regidated by the depth of 
 water in which tho caisson had to stand. In No. 1 comparatively little bracing 
 was needed, and only one tow post was required ; but in deep water tho caissons 
 were braced exactly as represented on tho drawing, and three white oak tow posts, 
 from 10 to 18 inches square, were used. None of tlio braces below the concrete 
 level were removed, the concrete being packed carefully under and around them, 
 but everything that interfered with tho masonry was taken out as tho work progressed. 
 No brace was, however, disturbed before it was actually in the way of the masonry, 
 and not even then was it cut out, until tho wedges had been firmly driven between 
 the stono work and tho sides of the caisson to resist the outside pressure of water 
 
 After tho pier was finished, the upper portion of tho caisson was detached easily 
 from the lower one by unscrewing the bolts by which tho two sections were connected, 
 and it was removed. 
 
 This first caisson was launched on the 13th July, 1870. As soon as it was in 
 tho water tho work of putting concrete into it was begun, and was pushed on 
 vigorously until 4 feet were in it, which caused the caisson to draw nearly 9 feet 
 of water. As this was nearly tho depth of the shallowest water at the site of the 
 pier, it became necessary to put the caisson into position before putting in more 
 concrete. It wjvs therefore towed from tho service ground, and placed in position 
 on tho 4th August. The method followed in placing it was as follows : — 
 
 Tho caisson was towed down tho Ilivcr until within a distance of 600 feet 
 of the position it was to occupy. An anchor was then dropped from its bow, and 
 the caisson was lowered very slowly by letting out the cable attached to a tow-post 
 imtil its stem reached the point which would bo ultimately occupied by its bow. 
 A diver was then sent down to examine the ground upon which it would stand. 
 Ho reported the bottom smooth rock, with only one large boulder, which was 
 removed. Tho reason for the examination of tho bed of the River being deferred 
 until the caisson had been lowered to near its permanent position, was the impossibility 
 of a diver working in tho current until protected from it by the caisson itself. 
 When tho exploration of the site for tho pier had been completed, the caisson was 
 again lowered down the stream until its stern was 19 feet below the centre line 
 
I 
 
 ■t 
 
 of tho Britlgc, lit wliicli tlistiinco IVoni tlic sti'iii, iiml immllol to it, a hcnni wan 
 spiked across tho oiiisson into wiiirli liircc poles wciv inserted, ono nt pucIi end with 
 a white fln^; attached, and ono iu tho eentro witli ii red lhi>,'. Thoso picketH woro 
 for tho observers on shoro to sij,dit npon when f,'ivin<,' tlie position. When tlio nvisson 
 was far euouuli down the stream, — whieli was known from tho sipiials disphiyed by 
 the person at tho instnimiMit placed on tlio centre lino of tlie Ihidfje, attention was 
 given to tho si^^nals shown by tho transit man at the sontli end of tho base lino on 
 tho Canada shore, who, liavin;,' turned oil" the proper anj,'le from the base line, was 
 watchin),' tho jacket with the red tlajj in tho centre of the caisson. As soon as ho 
 gave tlio signal " all rij,dit," which was done by dtsplayiii}; a red anil white tlay 
 Bimultancously, the position of the caisson was a^^ain examined as regards tho centre 
 line of tho bridge. When the three ])oles or the cross beam oi tho caisson wore 
 brought into range with tho instrument on the centre lino of tho Bridge, and tho 
 middle pole Avas right with tho instnunent at the .south end of the base lino, tho 
 caisson was then exactly in position and w.is ready for sinkhig, which, in the case 
 of No. 1, was done partly by loading it with stone, and partly l)y letting water into it. 
 
 Tho operation of placing tho cais.son was exceedingly tedious and almost irritating, 
 AS the movement to bring it into lino M-ith one instnunent Avas apt to disturb its 
 position with the other, and it recpiired numerous trials to make it succeed. 
 
 In placing the caisson many details were introduced, some of which appear 
 too trifling to mention, but they were of material service, and answered their purpose 
 so well tliat they were rigidly adhered to during construction. For example, to 
 enable the men engaged upon the caisson to know approximately its position as 
 regards distance from the shore, a code of signals was arranged with the transit man 
 at the south end of tho base line, who had two Hag poles erected, ono with a red 
 and the other with a white flag : both flags could bo run up or ilown tho poles as 
 occasion required. 
 
 When tho red flag was at tho top of the pole, it jndicateil that the caisson was 
 a great deal too far west ; \yhcn half way down tho pole, it signified that tho caisson 
 was within 10 feet of being far enough east; and when within 3 feet above ground, 
 it meant that a movement towards the east of less than 6 inches Avas required. The 
 signals with the white flags conveyed tho .same instructions as to distances required 
 to be gone towards tho west. Both flags flying at the Ijottom of tho poles announced 
 that all was right so far as distance from shoro was concenjed. 
 
 For obtaining the positions approximately with respect to tho centre lino of tho 
 Bridge, the course pursued was very simple, being nothing more than placing two 
 flag poles on Squaw Island exactly in range with tho centre lino of the Bridge. 
 
81 
 
 Thoso poll's pnal)ln(l tlioso on thn tiij,' Itoat to lino tlio caiasons ho closoly, that signals 
 from tlui oh.s(M-vor at tlio instrument were nMiuirod for tlio fmiil Hiittiiif,' only. 
 
 Wlicn tlio tlin-o poli-s inscrtoil into tlio cfohh timber, HpiUcil to tho top of the 
 caisson 11> foot from its stern, wcro on tho axis of tho Bridge, tho lougitudhial coutro 
 lino of tho caisson was at ri;,'ht angles to this axis. 
 
 This caisson being tho first that was placed, a good deal of interest and somo 
 anxiety was felt when workin-,' it into position ; lint althongh tho operation was tedious, 
 comparatively little dillieiiUy was experienced. For tho purpose of steadying tho 
 caisson laterally, before it actually gi'onnded, hawsers were extended from it to tho 
 Canada shore. 
 
 After tlio caisson was in i)laco, a delay occurred in loading it Avith additional 
 concrete; tho consequence was that four days after it had been placed, the caisson was 
 lifted and moved HO feet east by tho water rising suddenly nearly two feet. 
 
 Tho accident, although excessively annoying as evincing a want of precaution, did 
 not cause much trouble, but it clearly and practically showed tho treacherous nature 
 of tho lliver, anil tho absolute necessity of being prepared for a sudden and unexpected 
 rise of water. 
 
 After tho caisson Avas fairly placed tho second time, two feet inoro concrete were 
 put in, making 6 feet in all. 
 
 Tho final elevation of the surface of tho concrete was 97.30. Tho masonry was 
 commenced at this level. 
 
 PIER No. 2. 
 
 The caisson for this pier was of the same general description as that for Pier 
 No. 1. Its length from stern to shoulder was 45 feet 9 inches, and from stem to stern 
 54 1 feet; its width was 17 feet 2 inches, and height 20 feet. There was no occasion 
 to frame its bottom irregularly, as tho bed rock upon which it had to stand Avas quite 
 level. Tho sides and bottom Avero sheeted Avitli plank similarly to No. 1, and the seams 
 betAveen tho planks Avero caulked. They Avere also heavily payed over with pitch, as 
 it Avas desu-able to take additional precautions against leakage. OAving to tho greater 
 depth of Avater, a regular system of internal cross-bracing was introduced to prevent 
 leaks, and resist the pressure of tho external Avater. 
 
 This caisson Avas built to tho full height on tho stocks. It consisted of two sections, 
 the lower one being H feet high, tho upper one 9 feet high, to be removed at the 
 close of the Avork. 
 
 It was launched on tho 6th August, 1870, and was loaded with concrete to a 
 depth of 7 feet before being removed from tho service ground to near the position 
 it was finally to occupy. , 
 

 II 
 
 II 
 
 32 
 
 Before attempting to take it down the River a lui^^o barge was lashed to each 
 side of it. " These barges a(Uled very much to the steadiness of the tow, while they at 
 the same time did away with all risk of the caisson being upset in the current. 
 
 Before moving the barges and caisson from the wharf, the former were loaded with 
 broken stone, sand and cement for the concrete, so that the wdrk of putting it into 
 the caisson could be pushed forward the moment it was in place. 
 
 In lashing the barges and caisson together care was taken to connect them in 
 such a way that the latter could sink iutlependently of the former. The barges 
 were about 40 feet longer than tho caiss(ju ; they we.'e allowed to project beyond it at 
 each end, and were connected by chains stretched across each end of the caisson. 
 
 In this way the caisson was embraced between the barges without being actually 
 connected, and could consi'quently bo simk without them. Before describing tho mode 
 in which tho caisson was taken do^vn the River, and the method adapted for determining 
 tho position of the point at which its anchor was to be let go, it may not bo out of 
 place to remark that precisely tho same course was followed for taking down and 
 anchoring all tho caissons subsequently placed as was piusued for this one. No other 
 plan, possessing greater advantages, suggested itself during the progi-ess of the work. 
 
 These observations will save a good deal of repetition when describing the 
 foundations of the other piers. 
 
 On the 1st September, 1870, tho caisson was floated down tho River, guided by 
 two tugs, each attiiched by hawsers to the two jjosts of the caisson. Working the 
 engines of the tugs sulliciently to control their movement in tho current, gave tho 
 required direction to the caisson, and allowed it to descend the River with a velocity 
 somewhat less than the current. Tho anchor was dropjiod when 600 foot above the 
 Bridge, and tho caisson itself was io'.'ered very gradually down tho River by letting 
 out the cable, as was done in No. . 
 
 As it neared the point at which tho anchor was to bo dropped, tho engines of 
 the tugs by degrees worked up to such a speed that tho caisson was held nearly, if 
 not quite, stationary. 
 
 This wao necessary, as the point at which tho anchor had to bo lot go had to 
 be determined instrumentally from tho shore. 
 
 The way of doing this was to put up two flag poles on shore in a lino parallel 
 to and 600 feet distant from tho axis of tho Bridge. The bow of the caisson 
 was brought into this line, and was then moved east or west in accordance with 
 signals given by the observer stationed at tho south end of the base, who had tiu-ned 
 off such an angle that tho lino of sight through his instrument intersected the lino in 
 which tho two poles were placed at the point in which it would •also be intersected by 
 tho longitudinal centre line of the pier produced u]) stream. 
 
 : I 
 
33 
 
 The anchor was dropped from the bow of the caisson directly the signal was given 
 that it was right, and it was then very gradually and slowly lowered down stream by 
 letting out the cable. 
 
 When the stern of the caisson was about 40 feet above the centre lino of tho 
 Bridge, and nftoi it had been furtlier loaded with concrete to within a foot of the 
 bottom of tho Eiver, a diver was sent down to examine tho rock. lie was able to 
 do this without any difliculty in tho slack water behind tho caisson. After having 
 examined the bed rock tho full width of the caisson, and for a distance of 6 or 8 
 feet down stream, and reported, tho caisson was allowed to go down stream 5 feet 
 more, when ho again examined tho bottom in advance of it. 
 
 These operations, of letting down tho caisson and inspecting tho bed of the 
 River, were repeated until tho caisson was immediately over tho permanent site for 
 Tier No. 2. 
 
 Tlie bottom was found to bo of good character, requiring only tho removal of a 
 few boulders. 
 
 Three anchors were used for holding and for bringing tho caisson into place, 
 ono leading up stream directly from the bow, to which rofereneo has already been 
 made, and one at each side of the bow, nearly at right angles with the first, bearing 
 a little up stream. In jilacing the caisson upon tho rock, tho same course Avas 
 followed as in No. 1. The operation, however, proved to bo nuich more tedious and 
 troublesome, owing to the additional depth of water ajid iucrea.sed current. Tho 
 greater part of three days was ecmsumed by it. The caisson was finally placed on 
 the 7tli September, ls70. Tho concrete was brought to tho full height, and levelled 
 three days later, when the first stone was laid. The elevation of the bed rock 
 under the pier was 84(M>, and of tiio finished surface of concrete upon which the 
 masonry was founded was JH]G4. 
 
 No "riprap" was put around either this caisson or No. 1, as tliero was no possibility 
 of any scour. 
 
 PIER No. 3. 
 
 Tho caisson for this pier was not built to tho full heiglit on tho stocks, but 
 was launched on tho Gth Sci)teml)(>r, 1S70, when only 20 feet high. It was 
 considered unadvisablo to put in all tho side timl)ers before it was in tho water 
 and partly ballasted with concrete, as it would have been top-heavy, with a tendency 
 to upset. 
 
 When it had been loaded with a few feet of concrete, additional timbers wore 
 built on until a height of 20 feet was attained. Sufficient concrete was then put in 
 
1 1 
 
 34 
 
 to sink it to the deptli of IX foot, hoiii*,' within one foot of the dcptii of water on a 
 reef extending across tlie Itivcr at tlic ujuxm- end of S(jiui\v Island. On tlio 8tli 
 October, 1870, the caisson was Hoatcd to within a short distauci> of the Bridgo sites. 
 Four powerful tugs wore re(|nirod for this service. Tiie side liar|j;es that wero 
 considered useful in phicinj; 2*.'o. l' wero deemed absolutely essential to the .safety 
 of No. 3. 
 
 The depth of water and strenf,'th of current at the site of this pier beinj,' very 
 much greater, it was thought advisal>le not to lower the caisson within 40 or yO 
 feet of the position its bow would ultimately occupy belore it was almost ready for 
 sinking, as it was feared that the great strain that would bo thrown upon tho 
 anchors might cause them to drag a little, and whether the anchors dragged or not, 
 tho caisson would certainly, while bi-ing loaded, descend the stream a few feet by 
 tho straightening out and tightening of the rallies. 
 
 After it was anchored, the work of putting on the timber rccpiired to bring it 
 to tho height of liO feet, and of loading it with concrete, proceeded satisfactorily 
 until tho evening of the 17th October, when a violent south-west winil began to blow. 
 
 IJuring tho night its force increased so much that the anchors dragged, and tho 
 caisson v.as carried about half-a-mile down the River, where it grounded. 
 
 During the gale the water rose ui»wanls of thnse feet above its usual level, and 
 continued at tlii:, height until the storm aiiated. The caisson was in consequence 
 carried much further on the bank than it would have been had the Kiver been in 
 its normal state when the anchors gave way, and added greatly to tho dillicidty of 
 moving it, as it became imbedded in tho giavel when the water .subsided to its usual 
 level. The season was getting late ; there was therefore no time to be lost in adopting 
 vigorous measures to bring the caisson back to its i)lace. A considerable quantity 
 of the concrete was immediately throv.;i ')ut, large holes were cut through each side 
 of tho caisson opposite each other. Just above the level of tho decks of barge.s, which 
 were placed one on each si<le. Through these !.>oIes heavy scpiaro timbers were inserted 
 long enough to reach across the caisson and barge.s. The cais.son was then raised by 
 means of lifting screws. The operation of lifting ,>-o large a mass was a .slow one. 
 
 On the morning of tho 24th Octol)er tho caisson was afloat again, and by means 
 of seven of the most powerful tugs that could be obtaine<l in IJuflixlo was brought 
 back to tho place from wheuco it had drifted, and where it was once more anclujred 
 with three anchors. No further accident happened to it, and it was placed on position 
 on the 2nd November, 1H70. 
 
 Fortunately, although tho rock at tho site of this pier was not level it was free 
 from any twist, and the caisson consequently was not distorted by the weight of tho 
 
3.') 
 
 concrcto and masonry, or aflected in its position. The inclination of the bed rock 
 towards tho cast, in the width of the caisison, was 6 inches; towards the south, or 
 up stream, it was 3 feet in tho len{]jth of tho caisson. 
 
 A .serions dillienhy was narrowly escaped on the location of this caisson, as but 
 ji few feet soutli of its bow a lodge of rock, presenting a vortical face of 4 feet 
 in heigltt towards tlie nortii, extended some distance east and west. 
 
 The average deptli of water at this pier was 28 foot, tho elevation of the surface 
 of concrete was s7;!((. At tiiis level tht^ ma.sotiry was begim, and when the pier was 
 fuiished the upper portion of the c^iisson was removed to concn.'te level. 
 
 Tiiis eai.sson was built in two sections, simihirly t<) those fcH' Piers Nos. 1 and 2, 
 and no material change was made iu its general form and constiiiction. Tho most 
 important alteration consisted iu the sheeting bi>ing dispeu.sed with. 
 
 It was found in (,'aissons 1 and '2 that the planking formed a skin much too 
 v.i.^.;, injured by the rough u.sage to which it was occasionally exposed. A blow 
 from a barge or a tng, particularly when it wius struck near the corners, was apt 
 to start the jjlanks and cause a leak. It was tliereforo considered much better, when 
 buiUling Caisson No. 3, to leave off the planking, and to caulk between the solid 
 timbers from tho outiiido. 
 
 Before it was launched its bottom was caulked from below. Each joint or seam 
 was caulked witli two "threads" of oakum; it was then " hawsered," and afterwards 
 received another "thread." In this way tho oakum was forced about four inches 
 between the timbers. All the scams were thoroughly pitche<l with wood tar. It was 
 found that this mode of caulking between the side timbers was much better tlian the 
 plan first adopteil of slieeting and caulking Itetwecn the planks, and was consequently 
 adopted for all the caissons built subsequently to No. 2. 
 
 PIEll No. 4. 
 
 From tho very beginning of the work it was anticipated that the most difficult 
 part of tho whole undertaking woidil bo fouuil at Piers No. 4, 5 and 0, as they 
 would stand in tho deepest water and be exposed to the most violent current. 
 
 As the work advanced during 1870, the formidaV)le nature of the task was clearly 
 realized. Tho ordinary current in tho middle of the River, when taken iu connection 
 with a depth of over 40 feet of water, was quite suHicient to make the operation of 
 sinking a caisson there one of a most serious character. And it was not reassuring 
 to know that the Mater was hablo to be raised by a south-west gale, in the course 
 of a few hours, 4 feet above its usual level, and tho current to be increased to twice 
 its ordinary velocity. 
 

 U' 
 
 I ' 
 
 When taking into consideration this last-mentioned condition, it must bo recollected 
 '[ that the destructive power of ninning water is not represented simply by the numbers 
 
 ' which indicate the proportion betw^cen the normal and the accelerated velocities. 
 
 ^ For, while the rate of movement is only doubled, the force of the water is increased 
 
 I accoi-ding to the sixth power of its velocity. As these south-AVCst gales, that causo 
 
 the rise in the Eiver, come up suddenly and without warning, it was essential, in 
 providing apphances, to be prepared for the worst that could occur. 
 
 Two additional anchors of the largest dimensions, with a full complement of 
 cable, were therefore provided. Each of these anchors weighed 4 tons. They were 
 such as arc used by the largest ships of war in the American Na^'y. Although the 
 magnitude of the task of placing the deep-water caissons was fully realized, no 
 apprehensions as to its success were entertained. 
 I While Piers Nos. 1, 2 and 3 were being built, nothing had occurred to produce 
 
 an impression that the mode of putting in the foundations, which in their case had 
 
 been so successful, would be found unsuitable when apphed to Piers Nos. 4 and 5. 
 
 i It was i\ot therefore thought necessary to make any changes in the plan of caissons 
 
 I further than to give them additional strength to meet the increased strains to which 
 
 i ' they would be exposed in consequence of increased depth of water and force of 
 
 > current. 
 
 I On the 20th September, 1870, a caisson was launched, which it was intended to 
 
 "" use early in the following year for Pier No. 4. 
 
 On the 5th May, 1871, it w.as floated to near the site of the Bridge, and 
 
 moored by five anchors ; the front one, or one directly up the River, being a 
 
 I ■ "Trotman," weighing 3^ tons. The other four were also of the largest size, and 
 
 were ranged two on each side, loading diagonally up stream. Before making the 
 .. final examination of the bed of the Kiver, and prior to floating the caisson directly 
 
 .over the site to be occupied by it, 11 feet more timber were added to it, making a 
 total height of 41 feet. It was then loaded with concrete till a draught of about 38 
 feet was obtained. An attempt was then made on tha 27th May to place it in 
 position. Everything went on without any trouble luitil the signal "all right" wa« 
 given, and the caisson had actually touched bottom at one point, when one of the 
 side cables, although formed of IJ inch iron, parted, and threw so sudden a strain 
 upon the remaining cables, that the anchors began to tlrag and the caisson to swing 
 violently from side to side in the current. After oscillating in this way for perhaps 
 nearly a minute, it grounded nearly 60 feet below the line of the Bridge. 
 
 About a week after, and before it was practicable to procure proper appliances 
 for raising it, a violent gale removed all that portion of the caisson above the 
 
37 
 
 concrete, about 12 feet tleep, and carrieil it down the lliver. No further attempt 
 was made to obtain a foundation for this pier duriny 1871. 
 
 Meanwhile, when endea^'()urinf,' to place a caisson for Pier No. 5, the unwelcome 
 discovery was made that what liad always been supposed to be hard rock at the 
 sites for Piers Nos. 4 and .'), was in reality boulders, with the interstices between 
 them filled with gravel. 
 
 As soon as this was known it became apparent that another plan for foundations 
 would have to bo devised, as all the loose material ovcrlyiny the rock would have to 
 be removed. 
 
 Mr. Hannaford, the Chief Engineer of the Company, having given the matter 
 his most careful consideration during the autumn of 1871, dctcnnined to use bottomless 
 caissons, which were to enclose water-tight caissons similar to those previously used. 
 
 Although the general idea of a bottomless caisson was approved and adopted, it 
 was considered of gix>at importance, before deciding upon its exact form and size, to 
 make a number of experiments with models of various .shapes and dimensions. 
 
 The plan of the caissons ultimately ailoptcd and used for Piers Nos. 4, 5 and Q 
 is shewn in Plate No. IV. Their extreme length, exclusive of the fin at the stem, 
 is 97 feet; their width, from out to out, 31 feet. The bow of the caisson pointed, 
 being formed of two short sides containing an angle of 90°. The stem is also pointed, 
 but much more sharply, forming an angle of only 60". 
 
 The experiments made with the models shewed conclusively that their steadiness, 
 M'hen lying in a swift current, was more affected by the eddy at the stern than by 
 the pressure of the stream at the bow. 
 
 Deducting the pointed portions at l)ow and stern of the caisson, the rectangular 
 part was only 54^ feet long. The walls or sides were solid for about 6 or 8 feet 
 from the bottom ; above this height they consisted of two " skins," with a clear space 
 between them of 2 feet. The bottom of the sides or walls is V shaped, shod with 
 a cast-iron shoe to protect the timber from abrasion, and to form an edge to penetrate 
 gravel or clay. This solid i»art was composed of three courses of vertical timbers 
 12" X 12", set close together and spiked with |-inch rag bolts between 2 and 3 feet 
 long. The outside of the outer row of timber immediately above the cast-iron shoe 
 is dressed down 2 inch(>s, so that a course of 2-inch planking, spiked horizontally to 
 the outside of the first course of vertical timbers, is flush with the face of the shoe. 
 In the inside of the caisson, horizontal timbers 12" x 12" are bolted to the inner 
 or third row of vertical pieces. 
 
 The object of the longitudinal planking on the outside and of the 12" x 12" pieces 
 on the inside of the vertical timbers is to tie them thoroughly together. The bottom 
 
' ! K. 
 
 • 1!, 
 
 p 
 
 ^ 
 
 1 ':' 
 
 of these vertical timbers, ami so much as was rccjuisitc of tlio inn(>r horizontal tiniiiors 
 spiked to them, wero l)cvcllc(l to present a ciiisfl imI^'c with lln> slofjo on the iiisido 
 of the caisson. Tlie outside of the caisson [jresciiti'd u vertical face from the edj,'o 
 of the shoo all the way to the top. As it was expected that the depth of f,navel 
 or clay into which it would be neces.sary for the caisson to penetrate wcmid be .small, 
 it was not considered worth while to make the outside of the walls with a batter to 
 prevent it from binding in the material tluDUgh whiih it had to pass. 
 
 From the preceding description it will ajtpear that the walls above the bevelled 
 portion at the bottom were 4 feet thick, made up, counting from the ontsith>, of 3 
 vertical timbers and 1 horizontal, .\bove this solid part they consisted, as already 
 stated, of two skins, with an interval of '2 I'ct between them. To ccmnect these 
 skins, vertical timbers, forming the inner or central part of the solid })ortion of the 
 walls at the bottom, were carried up in i)airs at intervals of about (5 feet all tho 
 way round tho caisson. These vertical timbers served a double jiurpose — to tie tho 
 skins together and to keep them at a uniform distance aj>art ; they also formed a 
 very strong connection between these skins and the solid section of tiie walls. 
 
 For the purpose of giving adilitional strength at the angles of the cai.sson, tho 
 timbers forming the inner skin, at vertical intervals of a k'w feet, were increased in 
 length, so that they might l)e extended across the space between the skins, and 
 dovetailed into the outer skin. The timbers of the inner skins, thus produced, were 
 halved into each other where they crossed. 
 
 To give stiffness laterally to the whole caisson 48 cro.ss ties were inserted. These 
 cross ties extended from side to side of the structure, and were dovetailed into 
 the wall timbers. Four oak snuljbing posts, or " bits," 18" square, were built in near 
 the bow, these were placed between beams, extending across the caisson, and at the 
 same time, to give additional strength, horizontal braces were carried frt)ni these beams, 
 extending across the caisson ; for tho same puqiose, horizontal braces were carried 
 from these beams forward to tho walls of the bow, these walls being made solid 
 where tho bearing of the braces came. 
 
 In short, wherever additional and exceptional strains were expected to occur, 
 extra resisting power was provided. Beyond the stem a fin or innnoval)le rudiler 
 (if such a term does not involve a contradiction) was carried out 2;') feet into the 
 stream to the depth of 24 feet oidy. 
 
 The caisson, before being launched, was built to a height of aWut 14 feet. 
 Additional timbers were then put on, and when a draught of about 18 feet was 
 attained, it was floated to the vicinity of tho Bridge. Before floating the cai.s.sou 
 down the River, which was done on the 12th June, 1873, a large can buoy wa.s 
 
nnclioroil in line of tlic sito of tlic ]>icr, nnd aliout HK» foot down stream, as a f,'iiidinf» 
 jioiiit for tloatin,!;' the caisson in tlio iijj;lit (iiroction, it lu-ini,' dosiniltlo, wlion anclioiinj; 
 il, thai it slioulil lio so locatoii as to avoiil tlio noocssity of niovinj,' such an unwicldly 
 muss as it prosontod with the liariics at its si(h' oilhor to tlio oast or wost. 
 
 When it was at tho spot for h'ttiiiL; i,'o the anchors, six powerful tnys, working,' 
 two and two al)roast, wore ro<|uirod to iiold tiio caisson in position. Hofore leaving 
 tho wharf tlio calilos woro all attached to the caisson, and tho anchors wore loaded 
 on tho .side barj;(>s, and wore so arranj^cd that they could ho dropped <jr removed 
 withmit their caldes foulinj,' with each other. Tho 2>hvn of anchorajie is shewn on 
 Plate No. VI. Anchors A, 15 anil (r were loaded on naryo Xo. "J, the two la.st 
 named bcinj,' deposited at the jioint //. Tho Anchors 1), ]•] and I'' were loaded tni 
 bargo No. 1, tho first named being at the point ,/•. As soon as tho bow of the 
 caisson had been brought into proper positiim, <iO(t foot above tho site for the i)ier, 
 tho Anchors (',■ G and 1) woro throwii oviM-board, ami tlie full strain was i>eiiuitted 
 to como on to them viry gradually by slowly rodiu-ing tho working of tho tugs. 
 Tho caisson was then allowed to descend the stream until it was about 140 feet 
 above its final position. The object in keeping it so far above its true jdaco was 
 to allow for the straightening out of the cables when tho full strain Avas upon 
 them, and for tho inevitable descent when the caliles were lifted, Avhich had to bo 
 done as each rise of five feet of timber was added t<} tho height of the caisson. As 
 .soon as tho caisson became stationary, at a distance of 140 feet up stream, tho 
 Anchors A, 15, E and F woro carried out aud dropped into positions shovra on 
 the plan. When these side anchors w(>re in place their cables were drawn as "taut" 
 as practicable, so as to keep as nearly as pos.siblo tho bow of tho cai.sson immovable. 
 Tho anchors 11 and I wore then carried tmt from the stern and the cal)lcs were 
 laid in festoon form. Theses anchors and cables were not intended to hold the stern 
 rigidly in place, but to steady it and coimtoract any tendency to sheer. In .short, they 
 were designed to act like springs or elastic bands in chocking and controlling lateral 
 motion in tho caisson. 
 
 Tho guidhig priuci[)lo in anchoring the caisson was to attach the cables as 
 ch)sely as possible to tho bow for tho purposo of holding it .stationary, as, if tho bow 
 could be kept immovable, it was not anticipated that there would bo any trouble 
 with tho stern, and in practice this was found tt^ be the case. When tho anchors 
 were all out the work of building up tho caisson was resumed. An additional height 
 of 5 feet was put on, and then it becanu> necos.sary to raise the cables to tho top of 
 this lift as they were becoming submerged by the sinking of tho caisson. This 
 work required gi-eat care. Each cable, with tho cast-iron chaulk through which 
 
r 
 
 40 
 
 it passed, was raised separately, and projjerly secured helbre another oiio was touched. 
 Two days were reciuireil for raising 8 cables the height of ;"> feet to top of caisson. 
 
 Notwithstanding all the care which was exercised in raising the cables, it was 
 found that the caisson went down the stream from 8 to 1(» feet each time the 
 operation was repeated, for which movement, however, provision had been made. 
 Each time the cables were raised the position of the bow of the caisson was taken 
 trigonometrically, and if it was found to have deviated from the longitudinal centre 
 lino of the Pier produced up stream, the error was at once corrected by cables 
 attached to anchors A, B, E and V. These repeated trials of position were of 
 the most satisfactory and reassuring character. It was fomul that the system of 
 anchorage was so nearly perfect that the oscillations of the bow wore confined to 
 2 or a inches. As the caisson was being built up by adding on the side timbers, 
 it became necessary to sink it more rapidly than by the weight of only the superimposed 
 material used in construction. This was done by partially filling the space between 
 the skins with stone and gravel. The plan of loading the caissons till they nearly 
 touched the bottom, and of adding more weight when they were exactly in position, 
 as done with those for Piers Nos. 1, 2 and '3, was found to bo defective. The extra 
 weight could not bo added instantaneously, and in the meantime there was great 
 danger of tho caisson changing its position. It was therefore determined to follow 
 a different course in sinking tho largo bottomless caissons by loading them before 
 attempting to put them into position, with sutticient weight to make them bear firmly 
 upon tho bottom, l»ut at the same time to give them sufficient buoyancy by some 
 temporary and easily removed attachments, keeping them afloat several inches above 
 the bed of the liiver until they were brought exactly in position, then to sink them 
 by the removal of the temporary flotation power. 
 
 Tho plan devised for that purpose was to lash together from 130 to 150 empty 
 
 coal oil barrels in such a Avay that by tho cutting of a single rope the barrels were 
 
 detached from the caisson, which immediately sank to the bottom of tho lliver. Each 
 
 !' barrel had a buoyancy of nearly 400 lbs., so that in the aggregate they represented 
 
 * a sustaining force of from 20 to 30 tons of 2,000 lbs. each. 
 
 Knowing the buoyancy of the 1)arrels and the size and weight of the caisson, it 
 became a matter of very simple calculation to determine how far from tho bed of 
 the River the caisson could safely be kept floating while being Avorkcd into position. 
 
 j ill J To give further security against any displacement of tho caisson, six iron bars, — 16 ft. 
 
 {;■ J, long by 4 inches in diameter, and sharp pointed, three on each side,— were dropped 
 
 I ';', through openings in the sides of the caisson at the same moment that tho lashing 
 
 I ji of the barrels was cut. Plate IV. represents some of the openings and iron bars. 
 
 r . ' 
 
 i1 : 
 
 I ill 
 

 41 
 
 These bars woro arrangod to have a clear fall of fully UO foot. On the 
 7th July, 1873, thi.s caisson was successfully placcil on the liottora of the Ilivcr. 
 The courso pursued in giving its position was substantially the same as that followed 
 in placing Piers Nos. 1, 2 and 3. 
 
 As soon as the barrels could bo removed from the interior, divers were sent 
 down to examine the bottom of tho lliver. Their report was looked for with much 
 anxiety, us there were diflercnt opinions as to what it would be ; but the prevailing 
 impression was that tho bed of the Kivcr was rock, Avith a very thin covering of gravel. 
 
 Tho divers reported that about half way along the caisson a gravel baml extended 
 transversely, upon wliich tho caisson rested, but that it was not bearing at either end, and 
 that at each end tho bottom of tho lliver was rock. This intelligenco was satisfactory, 
 as no difficulty was anticipated in removing tho small quantity of gravel which was 
 reported to overlie the rock near tho middle of tho caisson. Hand-bags were lowered, 
 and placed by tho divers to prevent tho strong current from rushing in through tho 
 opening below the shoo of the caisson near the Ijow. One of Morris and Cumming's 
 dredges was then set to work to take out tho loose niaterial from tho interior of tho 
 caisson. Tho material dredged up apparently confirmed the report of the divers, as 
 it consisted principally of loose shale, such as is frecjuently found overlying rock. 
 As it was determined to remove tho whole of this loose material, tho dredge was 
 kept steadily at work for several days ; but to tho great surprise and disappointment 
 of all concerned, it suddenly broke tlirough the hard crust into soft material. A few 
 more hours' work unmistakably revealed the fact that the bed of tho River at this 
 point coiiS!i:t»d of a hard shell of indurated or compacted gravel, intermixed with 
 flat stones, overlying 9 feet or more of coarse sand and crushed shale, under which 
 the rock was found, at a depth of 48 feet lielow the siu-face of tlie Kivcr. The depth 
 of water where tho caisson stood was 38 feet before any dredging was done. A 
 most arduous undertaking was before us, — to remove a tlcpth of nearly 10 feet of 
 this loose material from tho whole area of tho caisson. Tho most difficult and slowest 
 portion of tho dredging was to break tin-ough tho hard surface. Tho course pursued 
 in Avorking tho dredge was to take out longitudinal trenches on each side, close to 
 the caisson. Tho divers then removed tho material from under tho shoes, and pulled 
 it into these trenches, from where it was taken up by tho dredge. Tho whole process 
 proved to be both costly and tedious, as tho hard crust had to bo taken out froni 
 under the shoes in small pieces by divers working in absolute darkness, and whoso 
 only guide was tho sense of feeling. Weeks of patient labour were spent before a 
 satisfactory settlement of the caisson took place. At length the difficulties were 
 surmounted : tho whole of the rock within tho caisson was cleared of gravel, and 
 
42 
 
 tho eniaflon itself sottlotl alninat to tlio rock. Tlic orosH tics wore at onco cut out, 
 and the inner caisson was Moated in on the sUi of Anj^ust. |s7;i, 
 
 This insido caisson was of tlie same {,'eneral form as those used for I'iers 
 No9. 1, 2 and 3. Its len^jtli was the same, hut its width was somewliat >,'reater, 
 heinj; IJ) feet. It differed chiefly from the otliers in the moih" of hracinj,' and in the 
 thickness of the bottom. Tlie (h'pth of water at fiiis pier was .so K''''iit, that it was 
 con.siih'nMl essential to use a stron;,fer system of liracin;.; than had yet been employed. 
 This consisted in holtinj,' vertical timlu'rs in pairs to tiie inside of the walls of the 
 cai.s.son. These timlter.s were H inches by 1^ inches, and were liolted with the wide 
 side n^ninst tho cais.son. The ilistaiice from centre to centre of each i)air of tind)crs 
 was about «) feet 4 inches. 
 
 The di.stunce between tho individual timbers of each pair was about 7 or H inches. 
 The twin timbers on one side of the caisson were exactly opposite to corresponding,' 
 timbers on the other. t'ross ties, .s\ich as were used on tho other cai.ssons, were 
 framed and dovetailed into the side timlicrs and between the alnive described twin 
 vertical tinilft'rs, and shouldered on both sides from '_' to '2h inches. Tho bow and 
 .stern were .supported in a similar niamier by loiij^itudiiial timbers e.vtended from 
 end to end of the caisson. This plan of bracinj,' answered admirably. Tho bottom 
 of the cai.s.son, instead of bein;,' composed of only one or two thicknesses of 12'xl2" 
 timber, was formeil of s courses of 12 x li' pieces, laid alternately longitudinally 
 and transversely. Tlie timbers in each course, excejit the botton one, which was 
 laid doso and was caulked and pitched, were jjlaced about an incii apart, and tho 
 interstices were filled with a grout of ei[nal parts of cement and .sand. Tho tindjors 
 in each course were .securely spiked by ;-incii sipiare drift bolts to tho course 
 below. A bottom formetl in this way was sullicicntly strong to bridge over any 
 ociuality or depression in the rock, and |)revent the danger of tho masonry being 
 fractured by any inieiinal settlement. Over this solitl timber bottom feet of 
 concrete were placed and the ma.sonry built ujion it. 
 
 riEIl No. -.. 
 
 On the Isth May, 1h71, nine days before an attempt was made to place Caisson 
 No. 4, another of the .sanu> description was launched for I'ier No. T). It was floated 
 to tho vicinity of the JJridgo site on the 21st day of Juno following. Although in 
 tho meantime the attempt to place No. 4 proved unsuccessful, it was considered that 
 by using larger anchors and more of them success might reasonably be looked for. 
 
 No misgivings had- yet been entertained respecting tho nature of tho bottom 
 of the River, or tho applicabiUty of tho plans that had answered so well m tho 
 esirlv stages of the work. 
 
4:5 
 
 III atlilition to tlio iinmon.so power roquirod to hold this caisson in place, in 
 t'on.s('i(ii(>nc« of its bciny in tlio tlcopost part of tho Kivcr and exposed to the 
 maxiiuiuii forco of current, provinioii iiad to bo made for strains under circumstances 
 whieii were of u wholly exeeplional and unexpected character, and from which 
 Cai.s.sons 1, '2, y and 4 had been free. These were, tho liability of being struck 
 liy rafts, Caisson Xo. f) lying in mid-channel for raft navigation. 
 
 It was tliiM-el'oro dt^terniined to use such a number of ancliors and strong cables 
 tliat there should bo no danger of their being broken by any force that would likely 
 bo applied liy rafts coming against them. An opportunity soon occurred for testing 
 tho strength of tho cables and tho holding power of anchors. Incidents connected 
 with it aro worth relating. 
 
 Three days after tho caisson had been iioatod to tho neighbourhood of tho Bridge 
 site, a raft of unusual dimensions canio down tho lliver. It was over 3,000 feet in 
 length and of about HO feet in width ; the timbers of which it was composed woro 
 large, and most of them over 00 feet long. 
 
 Immediately opposite Fort Porter (Bullalo) tho water rushes by at tho rate of 
 nearly nine miles an hour, while directly below tho velocity is reduced to a very 
 littlo over seven. The effect of this is, that unless tho tug towing tho raft has 
 sullicient power to maintain the head of the raft when it gets into tho slacker water 
 at tho speed accpiired in tho rapids, tho tail of the long raft, which still remains 
 in swift water, curv(;s rapidly down stream until tho rear part of tho raft assumes 
 tho form of an immense hor.sc-shoo. The raft in this form struck, and, it may be 
 said, embraced tho caisson ami tho bargos, exposing the cables not only to the 
 strain of tho full weight of tho raft, but to the hauling by tho tug steamer, which 
 worked to its full power endeavouring to straighten the raft. 
 
 In a very short time, perhaps not exceeding one or two minutes, tho sound of 
 crashing timber was heard and huge logs were seen to assume all sorts of irregular 
 positions. Meanwhile tho back end of tho raft had swung fully and fairly into the 
 stream, and the cables holding the caisson and scows were exposed to the tremendous 
 St lain of this huge raft and tug with a vessel attached to it. For a few moments 
 the whole confused mass remained stationary, then it began to move slowly down 
 stream, dragging tho eight largo anchors by which tho caisson was held. It grounded 
 near the lower end of .S(piaw Island, about 2,000 feet below tho Bridge site, in about 
 27 feet of water. 
 
 This accitlent was of a grave character, involving, as it did, a serious loss of time 
 and tho expenditure of many thousand dollars. It was all tho more annoying from the 
 reflection that it might easily have been avoided had those in charge of the raft 
 displayed oven ordinary prudence. 
 
'11 
 
 ■ I 
 
 Mi 
 
 44 
 
 After tho ftocidont, tlioro was no othor course to adopt Imt to tow the cnisson 
 Imck to tlu> (loik at Fori Kric^ and prcnarc it a^jain for licinf,' ant'liorcd a second tinio; 
 this was done on the I'ilth .Tune. Six powerful isteani t\i;,'s were re(iuired for that service. 
 
 IJy the 7tli .Tuly following', all the ei{,dit anchors l)y wliich the caisson had been 
 held wore taken up and re attached to it, and everything was in readiness for af,'ain 
 nnchoriuf,' it near the Jh-id'^'e site. On the followin;.,' day it was floated the second 
 tinio dowr. the Hiver, and setnred once more in the position it formerly occupied, By 
 the 12th August the caisson had been built to the full hei<rlit of 40 feet, and Hulllcient 
 concrete lunl been lilled in to sink it almost to the bottom. An attempt was then 
 made to place it, Imt, as was the case in No. 4, the numient the eai.s.son touched bottom 
 it bceame wild and unmanageable, and (!ra^',i,'e(I the anclior.s. It at lenj,'th j,'roundcd 
 not very far from its true ixisition. A few hours after, it was found to have heeled 
 over almost a foot towards the Canada shore. Next morning its west side had settled 
 three feet. 
 
 A diver was then sent (hnvn t<i examine the bottom, and after (several visits, reported 
 rock under the north-west comer of the caisson, with a covering of seven feet of gi-avel 
 over it. 
 
 As soon as tho fact was clearly establi.shed that the bottom of tlio Eiver was 
 covered by ^n-avel, it n'as decidoil to pump out tho caisson, ami to throw out of it 
 suHicient concrete to admit of its being towed back to tho dock. 
 
 It also Ijccamo at once apparent that it would bt lecessary to modify tho plans 
 for tho foundation of this pier s(j as to meet tho luiexpected dilReulty of a gravel 
 bottom, as it was essential that the pier should be founded upon rock. Owing to 
 tho season being far advanced, and to tho time that would bo recpiired to mature 
 plans to meet the exigencies of tlio case, it was decided to suspend all operations relating 
 to foundations luitil tho following y(!ar. Diu'ing tho autunui and winter tho bottomless 
 caissons, and general plans for fwunding Nos. 4, .') and G were designed. A full 
 description of these has already been given in the account of the foundation for Pier No. 4. 
 
 It may not bo out of place to remark that although all uncertainty as to the nature 
 of tho bed of tho Kiver under Pier No. 5 was flispelled, the same relia])lo information 
 had not been obtained by that time respecting tho site for I'ier No. 4 ; but to prevent 
 disappointment from want of that knowledge, it was considered advisable to use a 
 bottomless caisson for No. 4 Pier also. If tho bottom proved to bo rock no harm 
 was done, while if gravel was foiuid, it couhl be removed without difficulty. 
 
 The caissons for Pier No. 5 lieing similar in every respect to those for Pier No. 4, 
 no description is needed. The same applies to the anchoring and sinking; they wero 
 identicially the same for both piers. 
 
46 
 
 Oil tho l'»tli of Juno tho bottomloHM caisHOii tor tliis pior was launched ; on the 
 22'1'J of Auf,ni.st it was towod to tlio vicinity of tiio piaco whcro it was to bo sunk and 
 was thcro imchorod; and after hmv^ liuilt up to tho proper height, and prepared iu 
 all respects for sinking as was dono at I'ier No. 4, was placed iu position on tho 
 20thj Septcm)x«r, 1M72. 
 
 A great deal of trouble was experienced, whilst dredging, from somo old timber 
 which was found indiedded in tho gravel and oxteuding under tho sides of it; 
 also from several largo boulilers, soino of wliicli were also under tho sides and 
 prevented tho caisson from settling properly. With great dillieulty these were removed 
 by tho divers. A largo pino stump was also discovered and brought up. At length 
 tho rock was laid bare. It was foun<l to bo irregular, and of the form shewn 
 on Plato No. IX. Tho position of tho caisson was somewhat altered l)y tho 
 removal of tho" material from its interior. This, however, made no practical differonco, 
 as tho outer caisson carried no part of tho weight of tho pier; it was merely placed 
 to enclose a space of still water, to admit of tho rock being laid baro and prepared 
 for tho reception of a water-tight caisson. Those purposes it served ofliciently, 
 notwithstanding a littlo irregularity in its ultiraato form. 
 
 Tho next stop, after stripping tho rock, Avas to bring it to a level by filling up 
 tho low parts with stono. This was dono in a very efficient manner by tho diverss 
 The cross tics were then cut out and tho inner caisson floated in, built up and sunk 
 hi tho same way as was dono at Pier No. 4. Tho spaces between tho two caisson, 
 were then filled with stone throwai in at random, and tho outside of the bottomless 
 caisson was surrounded by " riprap," as shown on Plato No. IX. 
 
 PIER No. 6. 
 
 Tho outside or bottomless caisson used in founding this pier was essentially the 
 same as those employed for Piers Nos. 4 and 5. There were a few changes in 
 tho details, but they are not worth mentioning. 
 
 It was launched on the 27th May, 1872. On the 22nd Juno foUoAving it was 
 floated to the vicinity of tho place it was intended finally to occupy, and on tho 
 13th July it was successfully placed in position. 
 
 It was originally intended to carry this foundation to tho rock, but after dredging 
 about 6 feet in depth in tho interior of tho caisson, it was foimd to be impracticable to 
 go any lower, as tho material at that depth proved to be clay, upon which the dredge 
 made no impression. It was therefore detennincd to drive piles within the caisson, 
 and cut them oflF close to the bottom. Even this, although the simplest method that 
 
4« 
 
 could be adopted, was a work of very considorahlo difTlcuIfy. A trial pile was first 
 driven to ascertain tlio consistency of tlie l)ott(ini and depth to tlio rock. As the 
 clay was found to bo 15 feet thick, and the depth of water over ;{() feet, pih\s nearly 
 50 feet long were required. Tlic piles in this foun(hiti)n were not shod with iron, as it 
 •was deemed better to drive them to the rock and l)ruis(* tiie points a little by two 
 or three subsequent blows of the hammer, the weij^lit of which was 2,"2(>() lbs., with 
 a fall of 35 feet. Tlio whole space enclosed by the caisson was piled, the piles being 
 driven 3 feet from centre to centre. 
 
 Some doubt was entertained about the practicability of cutting off piles by 
 machinery 30 feet under water. The atteni])t was at the time looked ujion as an 
 experiment believed to bo wholly une.Kanii)led. The givat dilliculty consisted in 
 giving stiffness to tho shaft carrying the circular saw. The depth of water, as mentioned, 
 was 30 feet, and tho nearest immovable bearing of the .shaft was feet above water. 
 Tho saw was therefore working at tho end of a lever 30 feet long. When stillicient 
 pressure s brought upon tho saw to cause it to work into the pile, tho shaft had 
 a tendency to bend. 
 
 Another difficulty was that tho i)ile3 had to be driven and cut of!" before the cross 
 ties, binding together tho ends of the caisson, could be removed ; therefore, after cutting 
 oflf all piles at one side of a cross tie, the saw had to be lifted to the surface of tlio 
 water and moved over to tho other side. This involved tho raising vertically of tho 
 long shaft to which tho saw was attached, to a height of 30 feet — a work of great 
 trouble, and requiring gi-eat care, at the .same time of some risk to the men engagtMl 
 in it. 
 
 The drawings of the saw usod for cutting off the piles arc .shewn on Plate No. XX. 
 It answered its purpo.so very well indeed, and had very little tendency to get out of 
 order. 
 
 In water not exceeding 10 or 12 feet deep, 1")0 piles could be cut oft" by it in 
 ten hours, after it was got fairly into working order. 
 
 At Pier No. 6, in consequence of the extreme care which had to be exercised 
 to prevent tho shaft from being bent by feeding tho saw too rapidly, and of tho 
 trouble of raising it over tho cross ties of iIjo outer caisson and resetting it, not 
 moro than 20 piles were cut in tho same time. 
 
 Wlien all tho piles had been cut off, .stono was firmly rammed into the clay 
 between them by the divers. In this way a uniform paving, exactly level with tho 
 tops of tho piles, was prepared for the rccepticm of the inner water-tight caisson. 
 
 Tho cross ties of the outer caisson were then sawn off close to the sides. This 
 work waa likewise performed by divers. The inner cui»»on was Ouated iu on tho 
 
47 
 
 30th Aufjnst, 1872; by tlin 2(5tli Soptpnibor 5 feet of concrete had been phiccd in 
 it, and the first stone of the nia.sonry was hiid. 
 
 The inside caisson of this pier was exactly the same as to size and shape as 
 
 those used for Piers Nos. 4 and 5, exc;ept that the bottom was only 2 feet thick. 
 
 I'lEKS Nos. 7, 8, 9, 10 & llEST TIERS. 
 
 The foundations of all these piers were identically the same in principle. Piles 
 were driven in cai'li three feet from centic to centre, and Avcre then cut off at a uniform 
 heijiht close to the bed of the River. When this was not (piito level at the site of 
 the piei', as was the case iit \o. 7 and the rest pier, stone was rammed in between 
 the ])iK's and biouifht u]) to the level nf their tops. Water tight caissons were then 
 sunk on the piles with concrete. 
 
 The caisson for Piers Nos. 7 and J), beinj^' pivot piers, was octagonal in form, 
 40 feet in dianu-ter when measured at right angles to the sides. A caisson of tho 
 ordinary shape, rectangular at each end, was used for I'iers Xos.' 8 and 10, Avhero 
 there was no current. 
 
 For the rest pier — intended to support the upper end of main draw girder when 
 open — a caisson .")."> i'eet long and 1!) feet wide was constructed. The stern of this 
 was rectangular ; its bow was pointed, l)eing formed of two short sides including a right 
 angle, and was niaiK; for a height of about 12 feet, with an inclination or slope of 
 1 'o 1 ; above this its slope was ^ to 1. The face and shoulder of this ico breaker 
 were sheeted with boiler plate to high water mark. Tho sides of this wooden rest 
 pier were tied togetlier by iron rods, and the interior was filled with stone. 
 
 The rest pier for tho sui)port of the ui)pcr end of the draw span in tho Harbour 
 was a rectangular caisson, 12 feet by 20 feet; its longest side being parallel to tho 
 centre lino of the Ihidge. 
 
 This caissou renuired no ice-breaker, as there was scarcely any current in Black 
 Rock lIarl)our. To protect it, however, from being struck by vessels, a cluster of largo 
 piles was driven near its south-west and south-east corners. The interior of tho caisson 
 was iilleil with stone. 
 
 liounil each of these ])iers a large cpiantity of stone was thrown, to protect them 
 from the action of the current in the Itiver and from dredging operations in the Harbour. 
 
 These stones varied in size from about a cubic yard downwards. They havo 
 been found to form an ellicient safeguard in tho Iviver, not only against the scorning 
 action of tho water but also against tho ice. 
 

 48 
 
 FOLrXDATIOXS OF AliuiMh.MS. 
 
 There was very little difficulty experienced in founding the abutments. Abutment 
 No. 1 stands on the rock. 
 
 For Abutments Nos. 2 and 3, jiiles were driven, and were cut oft' 3 feet under low 
 water. These piles were driven in regular rows, 8 feet from centre to centre. On 
 the tops of these, caps 12 inciies s«iuaro were spiked, and transversely to these a 
 close floonng of 12 inch sipiare timbers was laid for the reception of masonry. 
 
 In AbutnuMit No. 3 concrete Avas tilled in and carefully levelled between tho 
 tops of the piles and the caps spiked on to tliem ; and between the joints of tho floor 
 upon which the masonry was founded, thin cement gi-out was poured. 
 
 The breast wall of Abutment No. 4 was piled, concreted, and prei)are(l for building 
 upon in tlie manner dcscriDed for Xo. 3. The wing walls were built directly from 
 the clay, which was hard and unyielding. 
 
CHAPTER V. 
 
 MASONRY. 
 
 In designing the snbstructnro of the International Bridge, the problem that 
 presented itself for solntion was to devise a plan of foundation whicli could bo 
 carried out -without the aid of fixed coffer-dams, and a ftjrni of i)ier that would 
 effectually resist the thrust of the largo ico fields which descend the Niagara River 
 during the ^nnter and spring of each year. The mode of setting in the foundations 
 has already been exphiined. 
 
 The pier that was supposed to meet the requirements of the case most fully was 
 one with an ice-breaker triangular in plan, and with the cutting edge retreating six 
 inches for each foot in height, the angle of the point formed by the two sides of the base 
 of the ice-breaker being 90°. This ice-breaker, in Piers Nos. 1, 2, 3 and 8, commences 
 at the smfacc of the concrete, and is carried up to an elevation of 11110, where it 
 is surmoinited 1)y a pp-amidal hood or cope-stone; in Tiers Nos. 4, 5 and 6 the 
 ice-breaker, as abovo described, Itegins at an elevation of 90, being 10 feet imder 
 water ; from this down to the top of the concrete it is still triangidar in plan, but its 
 up stream or cutting edge only recedes from the peri)endicular by an amount due to 
 the intersection of two planes battering 1 in 24. The reason for not carrying tho 
 ice-breaker all the way down to tho concrete on the same slope as the upper part 
 is, that tho length of the base of the pier would have been hicreased without 
 commensurate advantage. Ice fields never strike tho piers more than two or three 
 feet below the .surface of the water. What comes in contact with the ice-breaker below 
 this are masses of ice locally termed " Ciami)ers," and pieces broken off" the ice fields. 
 
 The former are generally so deeply inunersed in tho water, that their tendency is 
 not to rise upon the inclined .surface but to turn off" either to the right or to the left. 
 So far as they arc concerned, a vertical cutting edge is theref(n-e as good as a sloping 
 one ; with regard to the latter, they cannot climb the ice-breaker, as they arc portions 
 of tho field that are forced under when it is broken up by coming in contact with 
 tho pier, and, as a matter of fact, they do not strike the nose of tho ice-breaker when 
 driven down below water in this way, but impinge on the shoulders, and are immediately 
 swept past the side of the pier by the current ; consequently, in their case also, nothing 
 would be gained by lengthening the slopes of tho cutwater. 
 
 When a field of ice is broken up by striking a pier, the general tendency of 
 those portions of it which come directly in contact with the ice-breaker is to rise 
 
50 
 
 ujjon its sloping faces, and then fall oft" on each side ; and it will lie ohvions that 
 tho less the inclination of these faces, tlie greater will hv tlie probaliiiity of the ico 
 running a long way up them licfoii' falling off. Tiic tliorungli laiowlodgo of this 
 action of the ice which Mr. llaiuiaford had a(((iiired from many years' observation 
 on tho Victoria Ikidge at oSIontrcal, convinced him that the slope given to tiio 
 ice-breakers at that Ihidge— oms to one — would not answer at the International JWidgo 
 by reason of tho superstrneture of tlie latter being oidy •-'(• feet above low water; 
 if a slope of one to one had been adojited, tlie danger of ice running up tho 
 cutwaters and striking tlie trusses would hav(> been vi-ry great. 
 
 These considerations led to tlie ice-breakers being di'signeil with a slope of 
 inches horizontal to 1 foot vertical. Tho experience of three winters has clearly 
 demonstrated tho correctness of the oi)inion entertained in reh'reiiee to this matter. 
 The sliipc of the ice breakers has been fouml to be anqily sullicient to divide tho 
 ice easily, and at the same time not to be so great as to create any danger of its 
 coming in contact with the superstructure. 
 
 Piers Nos. 7 and 9 are pivot piers for supporting tho draw girders. They aro 
 built without ice-breakers, and are oetagcjual in plan ; they are 0-1 feet in diameter 
 under the coping when nu>asured at right angles to their sides. Piers Nos. 7 and 9 
 are biu.ked partly with concrete. They consist of an outsidi; ring of ma.sonry, 4 feet 
 thick under the cojiing, tied together by two cross wads which are likewise 4 foot 
 in thickness. The open spaces between tli'' niasoniy are filled with concrete, which, 
 during the work, was kept at a uniform lext-l with the stonework. It was not 
 considered necessary to attach ice-breakers to these piers. No. 9 stands in Black 
 Kock Harbour, where there is no ai)pri'eiable eiirrent ; No. 7 is exposed to ice runs, 
 but is snilieiently protected by the rest i)ier built up stream to support tho end of 
 tho draw girder when open, and by the crib-work exlending between this rest and 
 tho pier itself 
 
 Pier No. 10 is semi-circular, or bull-m)sed, up stream. 
 
 Tiie sides and ends of all tho piers, excepting I lie ice breakers, are built with 
 a batter of 1 in L'4. In Piers Nos. 4, ."> and (i, an olf-^et was made in tho masonry, 
 at an elevation of 90, or, in other words, at the bottom of tho ice-breakers. On 
 each side of all (pioins or angles a li-ineh margin draft is cut. 
 
 Piers Nos. 0, H and 10, upon which the ends of tlio draw girdei's rest, aro built 
 with a recess in width eipial to half tho breadth of tho pier, and ;] feet 2 inches 
 deep for their rece])tion. All the piers in lH)th I'.iidges, except tho pivot piers, aro 
 finished with coping Is inches thick, ami projecting ',) inches all round. In Piers 
 Nos. 7 and 9 the copuig is 18 inches thick on the outside, and 22]^ inches thick in 
 
.■)1 
 
 tlio r(>ntrr. Kor aliunt '.', feet Imck trmn tlio ontsidc" it is of a uniform thirkncss of 
 li-i iuclics, s(i lis Id atlnnl a Icvrl Im'iI lur llic lulh c plate; at tlic ccDtrc tlicro is also 
 ii level space, lieiii^' a circle ."> feet in diameter lur llie ])iv(it caslinj,' of the tnrn-tablo 
 to stainl upon. The copini:; of the pi\ot piets alMi projects i! inches. 
 
 The laces of ice lireaki'rs, surface of i npiiius. and bottoms and back walls of 
 recesses lor ends of draw }.;irdcis are linel}' hush liannncrcMl ; all the rest of the 
 masonry is rock or ()narr\d'aced ashlar. 
 
 .\11 ihe piers, except the ])i\iits, are linisiied at an elevation of ^'2^)^U^2. The 
 hi'd of the centre casting- on pivots is at an elevation of lltJtiO. 
 
 J'iers Nos. 1, i' and :> are '2^\ feet Iohl; ami 7 feet wide under co])in,fj ; Piers 
 iS'os. 4, ii, () and >< are :i>*,', feet loni; and 11 feet wide, at .same level; and I'ier No. 10 
 is iN', feet Ion;;- and s feet wide. 
 
 The ]ihiii of J'ier No. '_', as shown in I'late N'lll.. may lie taken as Ihe type of 
 Xos. 1, :! and S, in which the ice lireakers start inimedialely from the comrete. 
 
 I'lale Nil. iX., represent inn' ilelails of i'iei' Ni>. .">, represents also the p;eneral 
 form cpf I'iers I and ti. The octagon piers, Mos. 7 and 1>, are shown in I'late XI. 
 
 The form of reces.s foi' the ends of ihe swin;^ uirders may lie sei-n liy reference 
 to plan of I'ier Xn. (> in i'late X. 
 
 The alintmcnts are rectanL^ular in plaiij Ii(>in!f ')() feet wide and 40 feet lonj,' at 
 Iirid-^-e seat level, nr at an elevation of I'JO!':.'. At this level the hreast walls are 
 feel <! inches thick, and the wiii^ wails are '2!, feiil thick: these latter aro each 
 supported l>y two counterforts 4 feel liy '2\ feel. 
 
 .\l the hack nf thi- l>rid;;e seal, which is Is inches thick and projects ;} inches 
 lieyond the face of the al>ntmenl, a hallasl or rclaiiun,!.v wall. '2 feet lii.nh, is linilt. 
 The wini;- walls alMi\e the Mridyc seat are surmounteil liy parapets :J,^ feet high, 
 exclusive <if copinu, and •_' feel tiiick. The c<ipiii,y' is lieveled and is inches thick 
 in the middle; it projects ;' inches on each .side ol' Ihe jiarapet.s. 
 
 The plan of Alaitment No. •_' is shown on I'late \'II. 
 
 Aliiilments No.s. 1, "j .;nd 4 are counterparts of each other, except in the height. 
 The ^('lU'ial plan had to Ik- modilied a little to suit Ahnlment X'o. JJ, owin^' to the 
 eml of the draw ;.;irder re.>lin,i; upon it. It is re|iresenti'd in I'lale XII. ^Vll the 
 masonry in tlu" alinlmculs is (piarry or rock faced, except the tops of the copings, 
 the upper sidi's of the I'.iidge seals, and the front and top of lhi> liallast walls, which 
 are linely linsh-liannnered. The angles have the usual '2 inch margin draft.s to 
 pluuil) liy. 
 
 A portion of the stone used for the .sul)a<pieous masonry Ma.s obtained from a 
 cpiarry near the village of Dertie, about seven miles from the Bridge. It i.s a hard, 
 
52 
 
 cotnimct Muo liinostoiip, vory hoavy, ami cxcccilinoly diHicnlt fo worU. I'oitiinatcly nn 
 divssin^ was nvniirod i'or the lu-ils, as tin* strata were inTl'iM'tly |iaiMlIt'l ami witliuiit 
 
 1 
 
 J twist or distort ion. Tlio stoiu" was (|uarrii'(l with jiluLr ami fcatlicr. ami tlicrct'oro, with 
 
 j proper caro coiilil be takiMi out almost exactly ol' llic shape ami (liiuensious iieeiletl. 
 
 The courses vary from 14 inelies to :l icei in thickness. 
 
 For the masonry aliove watei- iieaily all the stone was hron.nht IVuni (icoi^ctown 
 on the line of the (Jraiul Trunk Kailway, L'it miles west of Toronto and 174 miles linni 
 the Bridf^e. It is a elose grained, solid freestone. Ii;;ht in colour, with occasionally 
 dark lines running,' through it, indicatini;- the luesenee of iroii. This stone has heen 
 largely used on some parts of tli(> (irand Trunk Kailway, and has been found to he 
 '} a most desirable and durable niateiial. The Credit ^■iadu(•t. the most imi)ortant 
 
 structure on the Western Division of the Uoad, was built of it, and after '•taudinu- 
 for nearly 20 years, the material manifests no symptoms of disintci^ration. in fact 
 it seems to have hardened and improved with a^e. Courses from 14 to 'M inches 
 in thickness were obtained from the (ieorj^etown (|uarries. 
 
 A small quantity of stone was got about ."> miles from Acton (a station H miles 
 west of Georgetown). This was of exactly the saiiu' (|uality as the (ieorgetown stone, 
 but was free from discoloiuatiou by iron. 
 
 A few lumdred yards of stone were alsf) brought from the lleii'a i|uarries, near 
 
 Cleveland, Ohio. This stone harmonized in colour and composition with that which 
 
 was procured at Georgetown and Acton. 
 
 . By the specifications the courses were allowed to range in thickness from 112 to 24 
 
 ' I inches, but as it was found when the (piarries were proju'rly opened up that very laign 
 
 .1 i material could be procured, the bottom courses weic made in several instances nearly 
 
 I ^ 3 feet thick, and no course less than 14 inches in thickness was used, for the 
 
 I ' sake of appearance, the thinner courses \\er(> always kept near the top. The top and 
 
 bottom .surface of every face .stone are dressed tin- full size of the stone and the 
 
 If heading points were cut back .s(iuare 2 feet from the face. The backing consists of 
 
 ii ■! heavy uncut stone, scob))led so as to lit as ncailv as i)racticable the ])laces intended 
 
 ♦I' li!' ■ • ■ . . , 
 
 il' for them. All interstices were carefully packed. Kvery stone was hiiil in a full bed of 
 
 I i;j| : mortar, and each course is thoroughly grouted. 
 
 In building the piers all the .stones compo.sing the ice-breakers, and idso the 
 quoins at the back ends of the piers, are clamped and doweleil together. The mode 
 of doing this is shewn in detail on Plate No. X. 
 
 It was originally intended to build the masoniy up to high water with cement, 
 and above that with cfunmon lime, but shortly after the work was begun it was 
 dctermiucd to use cumeiit throuyliuut. The (piuntilies of cement and sand were one 
 
 ll!' 
 
53 
 
 part of tlio f'oniK-r iiml Iwu of tlic latlrr. It, was fnuml that tljoso proportions 
 |.1(mIiic(m1 a iiK.rliir lliat M-t as Imnl as the .stunc itself. Tho oi'iiiont was ol)taimMl 
 at Akron, near liiiiralci. ll was inndc im|icrativc tliat it slioiiM alway.s bo broufjht 
 to 111!' woik ill liairi'ls ami iimI in l.iiik, as, if stnrcd in tiir latter form, it deteriorated 
 in i|iiaiity. 
 
 For tlic concrete a niiicli larger inujiortion of ccinent was u.scd, as it was mo.st 
 dcsiraMe that it slumld set (|iiirki_v. I'.y tlie s|)ecification, wliicli wa.s clo.sely followed, 
 the e(iiiciele was to consist of 1 cnliie yard of lime or sandstone Itrokon to go 
 throu-ili a L",-ineli rin^ and screened. 1 ,; barrels of cement, and an equal (piantity of 
 clear sliarp .sand. The stone was liroken by a JMake Stone-Crusher, worked by steam 
 power. 
 
 All the iiuiteiials for the concrete were loaded in proper proportions, but unmixed, 
 on to a scow, and were taken down to the I'ier. 
 
 The mode of nii\in-4 was to cover a space carefully mea.sured out on the bottom 
 of the scow, to a depth of <» inches, with broken stone. A convenient size was 9 feet 
 )iy <! fe(>t, as this area, covered with (> inches of stone, contained exactly a yard. Tho 
 proj)er (piantity of cement and sand were th(>n mi.xed and .spread evenly over tho 
 broken material ; water was then thrown on, and tho whole U)ai3.s turned over as 
 rajiidly as possible with shovels until the niateriaks were properly incorporated and 
 wheeled into the caisson. 
 
 As no scaifoldinj,' oi- false works of any kind could be erected in the Eiver, by 
 reason of tin; L^rcat di>])th of water and force of ciuTent, all the materials for the 
 nuLsonry had to l)e delivered in bar.Ltes laiil alongside the pier.s. The two largest 
 of these barj,'es were providccl with horse derricks capable of lifting with safety 5 
 tons each. These were used for hoisting: the stone into the caissons while they were 
 afloat. After the caisson was fairly grounded, a traveller — the plans of which are 
 shown in Plate XIX. was erected upon it, by means of which all the subsequent 
 hoisting and setting were done. 
 
 The icebreakers of I'i-is Xos. 2, I!, 4, f), (» and 8 are covered from the bottom 
 to a height of 4 feel above low wati'r liiu^ with wrought iron plating half-an-inch 
 thick. This covi-ring is fastened to the masonry by fixed bolts with countersunk heads. 
 The nose of the ice breaker above the armour is protected by a 4' x 4' x ^" angle iron. 
 
 Tho first stone of the IJridge was laid on the lUtli August, 1870, in Pier No. 1, 
 and tho last was laid in Pier Xo. 4 on the 4th October, 1873. 
 
ClIArTEH VI. 
 
 srricRSTia'CTi-iu;, and mhui: ci- K.\tsi\<i n 
 
 The truss chosoii for tlu* suiii'rstnicturc of llic Iiitcnuiiioiial I'riil^o wiis (lie 
 Liiivillc or I'ratt. wliolly fdiistriuti'tl ot' inm. Tin- i(iii,-.i(ltiali(iiis wliii-li led to iis 
 seU'c'tion \\\'\\' llio loiicct tlu'oiflical iiriiiciplrs iii\<i|\iMl in tin- anaiij^ciiu'iit.s u!' its 
 parts, and the I'ai t that in iiiacticc it liad ln'i'U I'mind to coiHliiiic all the desiderata 
 (if eeonoiiiy in cnnsiruclioM as \\<'ll as ol' d-.traiiiiity. There are, of eonrsi', many 
 othi'f _t;o(id forms ol' Irn-.^ in use each of which \\n-> its advocates ; Imt |ierha|(s, on 
 the whole, there is n.me whii !i has ^iven more L;i'ni'ral salisfaclion than tlu' " I'ratt,'' 
 jiarticnlarly >iiiee liu' inxcntion ol' the I'lioiiix \vron,L;ht iron eoinmn has |ilaced 
 wilhin the reach tif the l'ai;;ineer a eomliinalion of iron [lossessinj;- ;;reat strenj^th to 
 resist a strain uf eoniitression with the least e\|K'nililn"e of mateiial. The theori'tiea! 
 merits of the truss are —1st. The liiK's of .-trains are so cKarl_\ defined and easily 
 traced that each memlier can lie acimately iiro|portioned to lln' duly it has to 
 perforin. "Jnd, 'l"he strains of eominesiion and tension are so arranged tiiat the 
 former art' always either vertical or hori/onlal, with the exct'ption of the end posts. 
 :h(l. The height of the truss, ami the donlile >ysten\ of Irian.nnlation of \\hi(h it 
 consists, enalile a very liL;iit weh like arrangement to he adopted, while the yreat 
 height Ol' tlie truss rednces the thrust <in the toji ihord and the tension on the 
 lower (jue, wheichy a smaller t[uantity of iron is reijuired for their construction. ,V 
 very orroiH'ous opinion is lield by many wlio are unaci|uainled with tlu- princijiles 
 of liridge building', that a liyht tiii.-s is necessarily a weak one and that a lu'avy 
 one must be stroni;. This arises from overlooking the fact that it is only the 
 material which actually iloe.-, the work that .skives strenj;tli to the strncturi-, and that 
 all superfluous nu'tal is dead weight, and consei[nenlly a sonrce of weakness. Mot 
 only is the I'ratt truss corre<t in iiiinciple, bnt its jiiactical construction, as carried 
 out by the l'h(eni.\ville ('ompany, si-cnres tin- t;reatest possible i-conomy consistent 
 with thorough ellieieney ami dural)ility. The details have been simplified and 
 improved. The {general airaiiirenient of the jiarts of the I'ratt truss beinj^- familiar 
 to Engineers and to others who take an intei'est in iron bridges, tlu( description of 
 the suj)er,strueture of the International Bridge will be brief, and ju'iiu'ipally eonlini'd 
 to those iletails in which it diffi is somewhat from bridges of the same type. .Viid 
 as the (k'tails and eoimcetious of the vaiions parts of the fixed spairs are alike in 
 design and differ only in their dimensions, a description of the longest fixed span 
 of 124S feet will be suilicient. 
 
;i.i 
 
 Tiio tnisHos arc divided into iiinctecMi panda: their liei^lit is 20 tefit, which 
 hcif,dit, for tho sake of iiiiirnniiity, is luaintaincd in all tlio other sj)ans, whether 
 fixed or niovalile, except in the main swinf,', where it is increased to ',W feet in the 
 centre. Tlic ti'i> clionls and Ixitli end ami interior posts consist of J'lioMiix wronjjlit 
 iron colniniis. 'i'lu! Inj> riiot-d piccivs and end posts are composed of eij^ht sections, 
 tlic interior colinnii of fmir mdv. 'J'lie cml colnnins have a rake or inclination 
 towards the centre of the trn-<s e(|nal to the width of one i)anel. Tiicy therefore 
 slope at an an;;ie of al)oin (j:; : the top chord is made up of 17 hmi,'ths, that is to 
 siiy, I for each panel hetween the inelineil end posts. 'I'he seijinents or lenj^ths aro 
 conni'cteil Ity means of short castinL,'s with circular tenons Httinj^ accurately into tho 
 interior (hollow) of the chords. The top chord increases in weight froni the end.** 
 towards the centre of the truss. The interior diameter of each length is the ,sanu», 
 hut the se;.;nienls c( imposing; tliem vary in thickness. The lower chords are niado 
 up of links. A\ the end of earli tmiss only two links an^ used ; in the middle of 
 the s|)an there are eiiiht. These links are equal in h nj,'th to the panel width.s- 
 Tiie main lensinn rods and the counter liraces have a run of two panels, and are 
 conse(iueiUly inelineil at an an^de of 4.") , which, takin;n the truss alto^,'ethcr, is the 
 nio.st fav(nn'alile slope, as the maxinuun of stren,i;th is olitaineil with the mininnim 
 of mati'iial. The former, that is to say, the main tension hars are not adjnstalile; 
 tho hitter, the ccnniter liraces, can he re;;nlated as to leiinth hy union sci'cws, by 
 means of which any desiiahle strain may \w thi'own on the truss, and the viliratioii 
 caused l>y rolling' loads reduced. All the connections of the vertical trusses arc 
 made by means of pins. The tloor lieams are in pairs; they are 1.") im-hes deep, 
 with top and bottom tlan.u'es ."> inches wide, i;iviii,<;- a breadth of 10 inches for tho 
 support of tho hnigitudinal stringers. Th(>se tloor beams are .suspeniled«4i-om tho 
 trus.ses by 4 wrouirht iron loops —2 at each end of the beams. The horizontal 
 hitoral braces, i-equired to ^'iv(> rigidity to the tloor of the I>rid,!j:e, are placvl 
 between and are secured to the tloor beams. At the top the trusses an; kept 
 apart by lii^dit I'luenix cohunns cxtendinL!: horizinitally between the corresponding 
 joint boxes coinicctinj,' the hi>,i,'ths of the top chonls, and lateral bracinix is also 
 uiscrteil b(>tween them to nniintain the to]) in position. These braces are connected 
 with th(> top chords by means of wroiinht iron loops or stirrups. All the horizontal 
 braces aro secured to their attachments at the ends with screw connections, so a.s to 
 bo adjustable; tho uiiri.<;ht trusses are kept in a vertical position by anj,de braces at 
 the top, conneeteil with the perpendicular jjosts of tho sido trusses and tho horizontal 
 straininj,' tubes, which aro usimI to keep the top chords of the two trusses apart. 
 From tho above description, it will bo seeu that each span consists of 4 trusses — 
 
66 
 
 ■jl 
 
 , , , two vortical to nirry the whole static wcij^'lil of tlic I'lidp' tii;;('tlicr witii the rolliiijj 
 
 load, ami two liori/oiital to resist the I'urtc ol' winds and to iircvcnt oscillation or 
 |i ' side motion. 'I'lu* trusses rest on cast iron lud |ilates holled to the niasoni'v; one 
 
 I' \ |; I end ol' the truss ri'sts directly on the l)ed plate and i^ iniinn\iilile. the other iiears 
 
 li !,' upon I'ollers so as to admit of thi' expansion and (untraction of the metal in the 
 
 ' ;; trusses, 
 
 'I ; 
 
 ' '! The tloorinu; of the I?iidH;e is composed of four longitudinal strinj;ers with cross 
 
 ;, ties laid on them. The nmin or permanent way striiiLjcrs consist of two pieces, each 
 
 K l»y !>< , laid side iiy side, with a space <if aliout an iiieh lietweeii them. The outside 
 y stringers are sin;;le, and are o liy l.s". The cross ties are >> hy \'2 and are laid uiie 
 
 foot apart. Outside of each rail, ami al a uniform distance of eij^ht inches from it, 
 
 an oak guard piece (>" hy <j" is holted to the floor to proteet the truss in ease of engine 
 
 ' , or car runnin-;- ort". The most impurtaut departure from the ordinary practice of 
 
 ! construction was the sulistitntion of wrou;;ht for cast iron in the fixed .spans, wherever 
 
 I I the chan;,'e could he made with advanla?;e. In a majority of the I'ratt or Linvillo 
 
 Bridges huilt prior to l><7t> ca.st iron was used for the upper chords, and in .some of 
 , ij them the jiosls were of the .same material. In the International IJridge, Thienix wrought 
 
 ' [ i iron columns have hern employed for every nu'mher in compression, cast iron lieing 
 
 : !' only u.sed for the bed plates on the masonry, for the pedt'stals of the end and vertical 
 
 j Iji' ! columns, and for the joint hlocks of the top chord. From the ali<>v(! description 
 
 : i' I and examination of the drawings, it will he apparent that the (piantity of ca.st iron 
 
 1 ; !l has been reduced to the smallest amount, ami wherever used it is in such a form as to 
 
 ' avoid even a possiliility of its failing to perform the duty ii.ssigned to it. The main 
 
 tension rods and lower chord links aic composed of Hat bars, with eyes at each I'ud 
 
 for the rece{)tion of the pins by means of which the connections are made. These 
 
 I tension rods and chord links are formed without a weld. The ends which recpiire to 
 
 I be enhirged for the eyes are upset by hydraulic [tressnre and the eye is bored out 
 
 of the .solid metal. All the pins are acciuately turned. No wrought iron bar having 
 I an error of over l-t)4th oi an inch betwtu'u the centres of the pinholes is allowed 
 
 to be used, and in no ca.se was an eiTor of over l-Ktoth of the diameter of jnn or 
 hole permitted to pass. All the screw bars had their ends enlarged to such an extent 
 that the full section was preserved when the threads were cut. The abutting joints 
 
 in the top chords, in fact ill such joints in every part of the Bridge, were accui'ately 
 
 1' ' 
 
 planed or turueil. 
 
 In the swing girders the top and bottom chords are conii)osed of plates riveted 
 
 toci'ther. The use of links in the lower chords of these girders was, of course, 
 
 inadmissible. 
 
Till" tension rcids, instead iA' liaviiiH; an eye at oaeli end, have one only at tlio lower 
 end ; tlic n|(|ii'r ends pass tlirnn^'li the Inp chord, and are I'ornied as screw bars ho 
 as to allow of the Irnss lieinj,' aeeuiately adjusted hy tiH;hleniny or loOMOuing the nuts 
 at the ends of the iiais. 
 
 The turn tallies are of a ])attcrn desij,'ned at the I'lia-nixvillo Works, and are 
 shown in detail on I'iate No. Ki. 
 
 In the ((/iistrnction of tliese tallies :i novelty is introduced in planing; the cast 
 iron lied plates, on which the friction rollers travel. 'I'lie under surface of the heavy 
 rastinfTs aliove the rolhis was also jilaned. So accurately are tliese top and liottom 
 circles fitted, that althon^di the Joints of the sej;nients coinposin<; them can lie seen, 
 they cannot lie discovered liy jiassin;,' the liand over them on the planed surfaces. The 
 turn tallies are made adjnstalile, so that the whole weij^ht of the l'>rid<;o can be thrown 
 singly either on to the centre piers or on to the friction rollers. ]5y throwing it 
 wholly on to the former the l'iridj;c can be made to turn very easily, but ntit .so .steatlily 
 as when the rollers cany a portion of the weight. The machinery ftir turning the 
 Ihidge is worked by steam power, although ]>rovision is made for turning by hand. 
 The engines used on the swings are maile by Wilbraham and Jh'os., of I'hiladelphia. 
 They are double action uiiright engines with link motion. There are two cylinders 
 8" by I'S. The boilers are upright and tubular. The engines and boiler are placed 
 on the level with the tloor of the IJridge, in a hou.se outside of one of the girders 
 and innnediately above the turn tabli- ; on the opjiosite side of the turn table, and 
 also outside of the other girder, there is a corre.si)onding house, containing coal buidvcrs 
 antl watei' tank. For supporting the ends of the swing giiders when closed, cams 
 aie >ised ; these cams are raised and lowered by the same engines that work the 
 turn table, the coimections being made by a Hue of shafting extending from the engines. 
 I*\ir the purpose of locking the Bridge when closed, the rails of the pernuuieut way 
 are extended six inches beyond the ends of the swing, and rest in strong cast iron 
 chairs '2}," deej), bolted to heavy cross timbers on the adjoining fixed spans. These 
 end rails are not spiked down, but are arranged so that the ends which rest in the 
 chairs can be raised \i^ inches, to clear the sides of the chairs when it is necessary 
 to open the Ihidge. The raising of the rails is done simultaneously with the lifting 
 of the cams and by the .same machinery. A very ingenious indicator is placed in the 
 engine room to show the engineer when the cams and rails are either raised or lowered 
 sulhcicntly. 
 
 It consists of a long vertical screw working into a scinaro nut, which is fitted 
 between two upright guides which prevent the nut from turning. While the machinery 
 is at work, this vertical screw works hi such a direction that the nut is carried upwards 
 
r ;i 
 
 68 
 
 to a cfTtiiin point, wliirli wlion reached shows that tho Hridj^o [» uidocla-tl, the cnni.s 
 and rails raised, and ready fur (i|ieiiin;{. Thu actitm of the luaehiiiery lor idosiiij^ 
 beinj,' of eoiirse in an o|)|io.sito direction from that rei|nirod for raisinj; tlio cams, tho 
 : motion of the nut is downwards to a point near the i)ottom of tho gui(h's, which 
 
 indicates that tho cams and i-ails arc down, tlio swin;; closed, and th(! iJriilgo ready 
 for the i)assaf,M< of trains. 
 
 In tho earlier swin;,' lirid<,'es of hu},'o ilimensions which were built for railway 
 tralhc, the trusses were so adjusted that, when closed ami before beinj,' locked, theii* 
 ends wenrexactly at the proper level; that is to say, that tho surlaco of tho rails at 
 the ends of the dr,iwl)rid},'e eorrespomled exactly witii tho rails at tho adjoining ends 
 of tho lixed spans. In adjustin;,' tho swing girders in this way, tho very impintant 
 i.i li fact was overlooked that when only ono half tho girder is loailed tho iletlection in 
 
 this half has tho etl'ect of throwing such a strain on tho toj» chord that tho other end 
 j, of tho girder has a tendency to rise. Tho lift in some cases amounted to nearly 
 
 I of an inch. To counteract thi.s, the expedient was ailoptetl in the international 
 
 Bridge of adjusting the ends of the swing girders in such a way that when clo.sed, 
 
 and before tho cams were lowered, they should bo aliont J' lielow the level of tho 
 
 i fixed spans. Tho lowering of the cams raised the ends of the girders to tho proper 
 
 level. This plan answered peifectly, and now no vertical movement takes phico at 
 tho emls of tho swing girders under the i)a.ssage of the heaviest trains. 
 ,; j The iron u.sed in the constructicm of the Bridge was of the tougliest and best 
 
 kind manufactrnvd, and was recpiired to come nj) fully to the following I'laeuixvillo 
 tests, viz. : — 
 
 Uhiniato .strength tensile .strain, r)y,0O(l to ()t»,()U(( H's. per .sipiare inch, with no 
 permanent .set at L'."),(MH) to ;'.(»,()(»() liis. 
 
 Reduction of area at ineaking point average, 27> i»er cent. 
 Ehingation of area at breaking point average, 15 per cent. 
 Cold bend without signs of fracture, from 1)0° to 180°. 
 
 The manufacture of th(> various members of tho Bridge was all carried on under 
 inspection of an olllcer of tho Bridge Company, residi-nt at I'lKcni-wUle.^^ 
 
 For tho main swing the static load was assumed to be 14,4;!() Iks. 
 
 Rolling load 17,^4-4 " 
 
 Total 31,7741bs. 
 
 The lengths of this truss from centre to centre of end I'iers is 3r)8 feet. 
 AVidth of panels twelve and a half feet each, except the two centre panels which 
 are only twelve feet. 
 
 • For oitlcttUtiona of •tniiw in tpana of 248 and 197 feot, refer to VUte No. XVIII. 
 
 IIM. 
 
:.}i 
 
 Height of truss, 2<l fi-i-t nt tiuli cml ami :{<» IV'ot in tlii> middle. 
 
 For tho ti'ii.silo and coini»i'e.s.sivo .stmius j)niclically the wimo I'uctor of safety was 
 U8ud as for fixed NpauM, 
 
 A conipai'iHon of tlio above nientionod workiniL,' strains with the tests which the 
 best I'ha-nixvillo iron is wjirrantcd to stand, will show very clearly that the factor 
 of .safety 'isetl in dctcrniinin'' the dimensions of the various members of the trusses 
 was certainly a hi^h <»ne. 
 
 With r(.'n,uil to th(< mode of compulinf; the strains, it has not been deemed 
 desiralile to };ive it in dolail, as it is pi-ri'i'dly familiar to every Engineer. 
 
 No serious ilitliculty was anticii)ated or experienced in raisinj.; the superstructure 
 of the Bridge over lUack U(m1v Ilarlnmr, of .Si)ans Xos. 1 and 7, nor of the swing 
 girder in the Bridge over the Niagara lliver. A common staging, resting on piles 
 or directly on the rock in the bollom of the Itiver, was used. The only danger 
 appreheniled was from the ice, wlu'n the .si)an.s of the main swing wore being l)uilt. 
 These were begim in Septend)er, 1S7J, and were not finished until the 3rd January- 
 following, On the 12th December a very hi-avy run of ice occurred, which caused 
 some luieasiness while it lasted, but i'ortuiiately no damage was done. The best 
 mode of setting up Spans Nos. 2, 3, 4, 5 and 0, was, however, a matter of anxious 
 consideration. It wa.s impossible to drive piles owing to the rocky bottom in Spans 
 Nos. ii and 3, and to the grcut drpili of water and velocity of current in Spans 
 Nos. 4, 5 and 0. Several plans were discussed and rejected as impracticable. The 
 idea t)f a floating staging was the one which seemed to promise best results. It 
 was therefore determined to test it by actual experiment in Span No. 2. The plan 
 answered beyond the exi»ectations (.f the most sanguine, and was consequently adopted 
 in the erection of all the deep water .spans. 
 
 The floating staging con.sisted of three distinct parts, viz., the pontoons for the 
 support of the staging ; the lower staging, which extended no higher than the under 
 side of the iron floor beams of the permanent superstructure ; and the upi^er staging. 
 
 The pontoons — of ^\hich five were used for the 197 feet spans and six for the 
 248 feet — wore 5."! feet long from stem to stern, 17 feet wide, and 10 feet high. 
 They were rectangular at the back end and pointed at the bow, being of the same 
 general form as the water-tight caissons used for the piers. 
 
 Each pontoon was divided into two parts by a partition running transversely, 
 so that water could be let into one end only. At the bottom of this partition a 
 common hinged valve was placed to allow the water to run from one compartment 
 to the other when necessary. Each pontoon was also provided \vith two hydiunts 
 near the bottom — one at each end communicating with the water outside. 
 
'' 
 
 .'''!■ I 
 
 no 
 
 : 'I. 
 
 By means of tlicso the water could l)e lot in at iiicii-iUrc. Tliesi- pontoons w(>n' 
 placed eqniilistaiit from cadi other, and ihc spaces lictwccn tlicni and the piers were 
 one-half of the width of openin;jf between any two pontoons. ]'>etwcen tJic eml 
 pontoons and the piers, rafts were placed lo steady and prevent tlieni from sheering;. 
 Each pontoon was provideii with a t.iw post and loiu' >iiidiliin,u' posts two on 
 each side; the use of tlie latter was to ati'ord a l>earin,y' at tlie liaik of the sills ol' 
 the lower sta^:ing and to prevent the pontoon lieini;- drawn from under it. 
 
 Each pontoon was Iiidd liy one calde. All tlu' caMes were Ljatliered together 
 about 5(»0 feet above the i5ridj,'e. and were madi' fast to a single ])ontoon- a camel, 
 which was kept in place by three heavy anchors dropped about .")(»(» feet up the Hiver. 
 The staj,dnys were of a simjile but very strong character, and w(-r(> of the form 
 sho\vti on riate No. XVII. They consisted of two .systems of IVamin^', wholly 
 separate and distinct from each other, tla^ uj)pcr one merely restin;^ on the lower 
 one, but not fastened to it. On the top of the upper stajiin^' common railway bars 
 were laid to form a track to carry a powerful traveller used for hoisting- the various 
 parts of the iron srperstructure. This traveller is shown in the drawings. In 
 building the staging for yjian Xo. 2, the pontoons were Hoated singly between Piers 
 2 and 0, and the upper works were then erected. While the iron sujierstrueture 
 was being jmt uj), the whole staging was ke])t about 8 or 10 feet up stream, so as 
 to make provision against the anchors dragging during a severe storm. 
 
 The top of the lower staging was kept about a foot above the tO]).' of the piers, 
 to avoid tLo danger of the superstructure landing in an mifinislicd state on the 
 masonry l)y a fall of water hi the Kivcr. The determination of a safe height for 
 the staging was nearly a matter of certainly with the data furnished In the daily 
 observations of the rise and full (ji the River, taken n\cr a long period. 
 
 In building the iron work it was neces.sary to support the jiedestals or foot 
 blocks of the sloping end columns. This was done by lilocking up between the 
 under side of the first i)air of lower chord links, and the wooden cross lieam or 
 sill at the bottom of first, bent at each end of the top staging. IJetween the 
 pedestals at each end a straining piece was inserted of such a length that they 
 were kept exactly 20 feet apart from centre to centre. The pedestals were also 
 bound together firmly so that they could not separate more than :i(» feet. When 
 the iron superstructure was ready for being placed on the masonry, the pontoons 
 were lowered down stream to the jiroper position. IJlocks and tackle were then 
 fastened to each of the top corners of the lower staging. These blocks upon the 
 down stream corners were connected with the up stream ends of the piers, while 
 those on the upper corner were connected with the lower ends of tlie piers. 
 
(11 
 
 'I'liis tiickliiif? was used to stiNidy tlio cuds of Mic sta^'ing and to bring the 
 pedi'slals exactly over tlu; lu-d jjlatcs. 
 
 IJcforc sinkiii;^- tlic iMiutooiis. tlio ujukt staj;iii^' was secured to the inm work in 
 siH'h a way tliai it wdiild icinaiii siisix.'udcd when the pontoons were lowered 
 sullicieiitly to admit of the ImiHoip statin;; heiu;,' iloated away from under tlie iron 
 siipeistni Mile. 'I'his was done to avoid thc^ <hingcr of lifting the iron work by tho 
 lise of water al)o\c tlie niasoiiry. As soon as Span No. 2 was in position, the 
 pontoons, with tlie hottoni staj^in;^ remaining on them undisturbed, were lowered 
 (h)wn stream al)out 1(K» feet. 
 
 Four large tugs were tlien attached to tlic camel pontoon, to which the cables 
 of the ordinary pontoons were fastened, and tho wliole system was moved down stream 
 ronml tlie east side of I'ier No. ;! and back into the space between Piers Nos, 2 and 3 
 to receive the upper staging, which was meanwhile being taken down from Span No. 2. 
 As Spans \os. 4, .") and li could not be proeei'ded with when Span No. 3 was tini.sbed, 
 both stagings were taken down, and, together with the pontoons, were stored away 
 for lutiire use. 
 
 The first span for which it was afterwards required was No. 6. In the erection 
 of tho siipeistiucture of this span, the same course was followed as in Nos. 2 and 3. 
 When tiie iron work was in place, the pontoons, with tho lower scaffold, were towed 
 round IMer No. ."> and u}) the stream to a position above Span No. 3, where they 
 were allowed to remain until Tier No. 4 was completed. Seven powerful tugs were 
 re(|uired for this service, owing to the greater length of tho span and the additional 
 force of the current in the middle of the river. 
 
 When the masomy was finished, the staging was moved into placo between Piers 
 N ;. 3 and 4. The operation of moving a structure 240 feet long and 40 feet high 
 exactly into position was one reipiiring nuich care. 
 
 The method adopted was to jilace a large anchor directly above tho centi-c Span 
 No. 4, 1,200 feet up stream. The ealile attached to this anchor was then carried 
 over and connected with tiie camel pontoon. The cables of tho other two anchors holding 
 this pontoon were then gradually .slackened, ami the .strain allowed to comc on to 
 the cable first iilaced aluive the centre of Span No. 4. In this way the staging was 
 brcnight directly above the [tlace intended for it, and all that was then reipured to 
 be done was to slacken the cables connecting the pontoons supporting the scaffold 
 with the camel. When Span No. 4 was coiepleted, the mode of transferring 
 tho pontoons to Span No. o was changed. In.stead of lowering and hauling them 
 rouii I, they were drawn up stream about 3()(» feet aliove the Ih'idge, and were then 
 moved iulo place in tho same way as they were from their position above Span No. 3 
 

 ii> 
 
 ' I. V: 
 
 ' I ' . ' ' 
 
 to Span No. 4. Tho operation of drawini,' the pontoons np from S])an No. 4 was 
 laborious ami tedious, pai'tieul;iily ill its early sta^e, wlieii tiie pcnitooiis were weiffhtcd 
 down with water, which eould not he pumped out till the stauini; was (piite clear 
 of tho iron suporstnicture. Two tuijs were eniployeci in hauliiii;- the pontoons up 
 stream on their o>vn cables. Two days were eoiisuiii(>d in aeeoitiplisiiin;; tliis. 
 
 When the six pontoons used in the erection of the 'J4ii feet spaivs were fully 
 loaded with all the false works ami the iron superstructure, their inunersion was four 
 feet while that of the camel was about five feet. Tiie suugestion to use a floating 
 scaffold for buihlin.u' the iron work was \iewe(l with considerable (hmbt. A tloatiiifj; 
 stapin<^ for tho erection of a rit^'iil structure, Avliich rei|nired to be phiced with (>xtremo 
 ^i accuracy, was a novelty: but as no other plan seemed to otfcr such yootl chances 
 
 of success, it was decided to try the ex])eriment. 
 
 As already stated, it an.swered the ])urpose admirably. 
 
 In some respects it was decidedly better than an ordinary scaffohi built on tho 
 bottom. Any irre;,'u!arity of shape in th(> stai^iny- when alloat was more easily rectified 
 by filling in and immping out water than it einild have been on a fixed one. 
 
 The operation of sinking the jumtoons to let down the iron work on the mas(mry 
 was exceedingly simple and thoroughly under control. 
 
 The inflow of the water could also l>e regnlatiMl Mith great ease and exactness^, 
 * and tho iron work lowered at any desired rate. 
 
 Tlie time taken from the opening of tin- hydrants till the iron superstructure was 
 re.sting .safely on the piers was from half to three !|uarters of an hour. 'I'lie first 
 piece of iron for tin; .superstructure was raised on the 17th .Fniie, Is71, and the hist 
 span, No. 5, was lowered into place on the -iinh October, l><7o. 
 
 The Bridge was opened for the passage of trains Ity Mr. Ifichard Totter, 
 President of the Grand Trunk Railway, and by Mr. C. -T. IJrydges, I'resident of the 
 International Bridge Company, on the third day of November, 187:!. 
 
CIIArTER VII. 
 
 I c i; . 
 
 Rof(>ronco lias aliunidy I toon mailo to the large (luantitios of ice which pass down 
 the Xiayai'ji Rivci', ami to predictions as to the destructive force it wovdd exert on 
 the piers. 
 
 The desi.uiiers of the structure had full coufidenco in the stability of the masonry 
 in the piers ; hut, as a matter of interest, and by way of further investigatini,' the 
 rpiestion of the force of moving masses of ice, it was determined to make a series 
 of exi)erim(>nts upon the crushing strain of ice, and to deduce from them, by calculation, 
 the forces which the masonry would have to withstand. Im'oiu a number of carefully 
 conducted trials, made at the Toronto IJoUing Mills during the month of February, 
 1S71, it was foinid that the eiushing strain of ice is 2()8':J:J lbs. i)er .scpiare inch. The 
 experiments wen- made with blocks containing exactly a cubic foot each, and were 
 sulliciently numerous for a thoroughly trustworthy inference I)eiug drawn from them. 
 
 However much oi)inions may ditt'er as to the action of ice against an inunovablo 
 body, there is one fact that nuist be acknowledged by all, which is, that the force 
 exerted cannot be greater than is sullicient to crush or disintegi'ate the ice which 
 comes in contact with that body. 
 
 Assuming this to lie correct, we have the following data from which to calculate 
 the .strains to which the piers will be exposed from ice : — 
 
 1. The thickness of the ice. 
 
 2. Tlie force recpiired to crush it jjcr square inch. 
 :). The area of masonry exposed to its acti(m. 
 
 4. The velocity of the current. 
 
 As Piers Nos. 1, '2 and ',] are uuich smaller than the others, and consequently 
 less able to resist a strain, the results of the t-alculatious made for them only will 
 bo given. 
 
 PIER No. 1. 
 
 Thickness of ice, '3 feet. 
 
 Area exposed, '30^2 square feet. 
 
 Current, 4 miles an hour; in reality, it is only 2^ miles. 
 
 The hori/ontal pressure necessary to set this pier in motion 
 
 down stream bodily is 1,222,500 lbs. 
 
64 
 
 The horizontal prcssuro uocessary to snt the piiT in motion >iili-\viiy.s hoilily is— 
 
 Towards the iiiiddlo of tiic strciiiii I»:{7,()0(» ilis. 
 
 Towards •' 9 .shore 1.474,7<i() Ihs. • 
 
 If tiio pn'ssiuT is applied at a point I'o \Wt from lii.- top, the pivssiire re(iuired 
 to overturn it is — 
 
 Towards tlio mi(hUe of tlie stream l,l(!fi.-_'ls Ihs. 
 
 Towards the siiore l,;j:!s,;3i:, li,.s. 
 
 The pressure (hie to the inisliinL; straiii of iee i.-; tNs.oso Ihs. 
 
 ij>uar-i fluid resislanee 
 
 •)-.) 
 
 iZ Uis. 
 
 Total maxinuim ])ressure of ice is *)>i^ :!.")!' llis. 
 
 PIKK No. •_'. 
 
 The data for tliis I>ier are the siime as for I'ier No, 1 , extH^ptinj,' of eonrse that 
 it stanils in deeper water, and that there is a tlitferenee of one or two inehes iu 
 the Avidth. 
 
 The horizontal pressure required to set Pier iu motion down 
 
 stream bodily is 1,41^,200 Ih.s. 
 
 To set it in motion sideways towards eeutre of stream ... l,li»l,it()(t Ihs. 
 
 To set it in motion towards shore 1 ^^50 4(^0 jj ,... 
 
 To overturn it sideways hy a hori.>:ontal pressui'e apjilied -JO feet bolow top 
 
 Towards centre of stream j,s5 1 ^5 i^.^. 
 
 Towards .shore 1,083,450 lbs. 
 
 Pressin-e of ice on Pier in direetioii of stream is duo 
 
 to crushin- strain 7:25,200 lbs. 
 
 Qua.si lluid resistanee 334 lbs. 
 
 Total maximum pressure of iee 725 534 lbs 
 
 PIElt No. 3. 
 
 Data same as before, except current, which is assumed to bo six miles per hour. 
 The height of pier from Iwttom of river is greater, and the area exposed to ico is 
 38.20 .square feet. 
 
 The horizontal pros.snre neces.sary to set this pier in motion 
 
 down stream bodily is 2 204 800 lbs 
 
 Horizontal prcs.sure rcciuircd to set it liodily in motion 
 
 sideways towards shore is 2,473,400 lbs. 
 
65 
 
 llori/ontiil | nvsMm; riMiuircd to .set it bodily in motion 
 
 sidoways towards centre of .stream is 1,801,500 llj.s. 
 
 Horizontal pre.s.snre reiiuired to (jvcrturn the pier (ai)i>lie(l at 
 
 20 fi'ct vtTtiealiy Ijidow top) towards centre of .stream is 803,050 lbs. 
 
 Horizontal pressure reipiiied to overturn the pier (a])plied at 
 
 'JO feet vertically liclow toji) towards .shore is 900,040 Ib.s. 
 
 Pressure of ice on i)ier in direction of stream due to jru.shiu"' 
 
 «t''ii''> i« 758,800 Iks. 
 
 (Juasi thiid resistance 7;j8 !)«. 
 
 Total niaxiinnui , re.s.sure of ice is 750,538 11 is. 
 
 The reason for calculatin}^' the pressure i'e(|uire(l to overtiu'n the pier applied 
 20 feet vertically below the top is, that it was .supposed tliat po.s.sibly ice nii-ht become 
 wed^^'.l or packed lu-tween two piers, and have a tendency to overturn tluun sideway. 
 
 The height of the piei's above water was assumed t(j bo 20 feet, althouyh in reality 
 it is 21 feet, the ditfereuce beiug in favour of stabilitv. 
 
 All the calculations made to determine the forces recpiired to move or overturn 
 the piers were made upon tlie as.sumptiou that the piers were standing alone, and 
 Avithout the superstructure resting upon tiiem. The sui)ei'structnro will add greatly 
 to their stability, not only by its weight but by bracing one pier against another. 
 
 Notwithstanding the fact that I'iers Xos. 1, 2 and 3 have withstood, without moviu". 
 the ice of three winter.s— two of them having been of lumsual .severity -and all the 
 other piers except No. 4 were also exposed to the ice of last winter, assertions are 
 still made that although the ice was of extraordinary thickness during the last two 
 winters, yet the Dridge has not been fully tested. It is a.sserted that dimng some 
 winter-s the fields ai'c larger and more numerou.s, but it is not said they are thicker. 
 The fact is o\erlooked that if the piers can stand against an ice field three feet in 
 thickness and of snilicient size to bring pres.sure enough against the pier to crush 
 the ice, they can stand against othei- fields which are infinitely larger. The size of 
 the field of ice makes no diH'erence whatever so long as there is no increase of thickness. 
 To assert that it does would be as reasonable as to tell a farmer that the draught 
 of his plough is determined by the size of tho field ho is cultivating. 
 
 ■"o"- 
 
ERRATA. 
 
 Page 20. For " scour " read " scow," or barge, 
 " 25. For"C.E., M.A., I.E.C." read "C.E., M.A.I.C.E." 
 " 50. For " wads " read " walls." 
 
— -I 
 
 - . " fi ' r. , 2 s •* . ' . ' > Sj ■ 
 
 V 
 
 
 fit 
 
IXTKl {NATIONAL HhMnC.l 
 
 PLAN OF LOCATION 
 
 -.>-*lecfFpet nV: 
 
 ..u -..kS i '..nh 
 
 wmm 
 

 ^.tf 
 
 ?■ '"' 
 
 % 
 
 J-. ?. 
 
 
 t 
 
 f, 
 
 ■HMi!! 
 
 
^1 
 
 40' 
 
 ...193 5. 
 
 .19 7'. 
 
 
 H-r 
 
 ni 
 
 
 s 7\ 
 
 A 
 
 
 r- ,f ..f 
 
 j^j, 
 
 A I A 
 
 
 V /\ / x7 
 
 if It 
 
 XtA 
 
 
 lit 1 
 
 -I^H: 
 
 ^- 
 
 *-<«H 
 
 -V^- 
 
 
 '^ 
 
 T'TnrT'Tfw 
 
 \^x4VH 
 
 jh 
 
 immmdk 
 
 
i • 
 
 19 "7'. 
 
 2 48:. 
 
 Ill 
 
 T 
 
 ,fv ,1. > \ 
 
 fv i f 
 
 c 
 
 r 
 
 
 .y 
 
 . 
 
 ^ "^ ■^ '-^ 
 
 ^-rt^r 
 
 -V, 
 
 *rMW 
 
 ? 
 
 /- 
 
 -T'— ■ 
 
 L^ 
 
 ■7^ 
 
 JL 
 
 \/\/ 
 
 J^^ 
 
 ^ 
 
 ^ 
 ^ 
 
 ^r 
 
 :^ 
 
 i 
 
 
 
 /^ 
 
 L 
 
 \/ 
 
 ^-- 
 
 r^ 
 
 ^ 
 
 ^m\i<M 
 
 BRIDGE 
 
 AQl. 
 
 .-(„ 
 
 
 -1-4- 
 
 i f. .. .r.i . : ? ■ ■ [! -ii 
 
 \ /\/\ 
 
INTKHNATIONAL 
 
 ACROSS THE 
 
 NIAGARA RIVER 
 
 i]Hii)(;t:. 
 
 AND 
 
 ERIE CANAL. 
 
 MAIN 
 
 BRIDGE. 
 
 4 a 
 
 ..246' 
 
 TTT 
 
 
 i^^fc 
 
 ■7-t 
 
 -IUt 
 
 7\ 
 
 v/ 
 
 -A- 
 
 \ ' . / ^ 
 
 - z r \ / 
 
 -\t^ 
 
 X 
 
 / 
 
 % 
 
 t » I 
 
 A 
 
 j^ 
 
 A 
 
 X 
 
 A 
 
 ^^^^^^^^ 
 
 -A- 
 
 v 
 
 -T'-V- 
 
 r - - \r 
 
 7^ 
 
 /? 
 
 I/) 
 
 •\ ^\ 7\ / 
 
 X 
 
 ^/ \/ 
 
 vy- 
 
 A 
 
 i; 
 
 v-/ 
 
 JL^ 
 
 X 
 
 T 
 
 \/ N 
 
 ' \ 
 
 N 
 
 19 6.7. 5 
 
 
 3E ACROSS BLACK ROCK- HARBOUR OR ERIE CANAL. 
 
 .......io/:. _ , in: „ ,. ~ iiia:. 
 
 
 ■f 
 
 ■:4a' .;.. 
 
 'I :ii : ^. :.; IN / \ / ■ 
 
 iUV-i — i-+> ■^\ •'-V- 
 
 w 
 
 
 / 
 
 7\ 
 
 *- ^ ^ ^ -^ '^ 
 
 X 
 
 517.' 
 
 C;f>. "'.jrtc ^ '.'^ Mth Tor :ti>'>. 
 
 
 
m 
 
 ± 
 
 IT' 
 
 \/ N/ 
 
 V 
 
 A 
 
 '-■w-C 
 
 ^A 
 
 
 A 
 
 
 ~V-/- 
 
 -A- 
 
 ^ 7F 
 
 V 
 
 / 
 
 v 
 
 v^ 
 
 V 
 
 \;;i 
 
 / .i'- 
 
 X 
 
 *w 
 
 ■^^. 
 
 -AT 
 
 \ / 
 
 M 
 
 W7\ 
 
 m 
 
 ]\ \/ 
 
 7 \ 
 
 X 
 
 5*yy^j^^p.- 
 
 •i'-'I "■•■''J/ .?-'>''•>;> 
 ■■■• •• c- <i-'- -.% -y.^' 
 
 ,4U 
 
 iii" M 
 
 I'll 
 
 ifii 
 
 ;!.: ^::rjj-i .: 
 
3l-<-' ll. 
 
 
 ^^y^^-^i^&'^f^h^ki^. 
 
 4i 
 
 A, 
 
 -A 
 
 -t 
 
 --^:4:X, 
 
 -A-; 
 
 \^mmk 
 
 E 
 
 ■ / V J 
 
 -^-\ 
 
 A 
 
:j 
 
 c 
 
 U-i- 
 
 X 
 
 ^■.:^ 
 
 -:r--r 
 
 V '^ ' -' r A^ ' 
 
 v/ '** » '' V 
 
 '^^.^^,4... 
 
 , -i_ — ^h^^ . , ■ " " — ' ■ -f .-.— 
 
 "T 
 
 
 7fe-^\^ 
 
 i<: 
 
 --^ 
 
 "^v 
 
 lid 
 
 :=^+ti~. 
 
 I 
 * 
 
 T' 
 
 c: 
 
 !■ : ; 
 
 L 
 
 - |- 1 ! ■ 1 ■- ^ • { 
 
 f"" 
 
 ^"■~| y • T 
 
 
 
 
 
 
 
 r ;/■; . 
 
 
 
 
 ■ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . : . 1 . . . 
 
 , . u^■^Cf.:'.;" ^ - - * - '■' v-'H'c;''^^ >•-■ ^■-:^'-Oi»iJ 
 
 rJ^.^->/ 
 
 ''^J',.-'^-^'^. 
 
 ^^-;-v-^^ 
 
 ..v-^- 
 
 .=^ ^-y 
 
 "" ;. ■ - . - 
 
 .,'^..^. .., ; 
 
 
 , -^v^ 
 
 A ' 
 
 ^^A-^- ■ ■ ■ 
 
 - i ■ t ■ 1 j • 1 
 
 
 
 ~ ■^' 
 
 
 ""' •■ 1 
 
 
 t_ ■ ^^ 
 
 
 ,'v,.' '~T>'\^' .-31--, 
 
 ^^'^^•rj^-^c'-^ 
 
 ■ 1 : ■ ; i i 
 
 
 
 1 
 
 
 ■ i 
 
 
 
 
 
 i ; - - . 1 - . 
 
 — - 
 
 
 
 
 ■ 1 
 
 
 ■ 1 
 
 
 
 
 
 : 1 ■ ■ i ■ 1 j ■ 
 
 
 
 
 
 . , ; . 
 
 
 I 
 
 
 
 
 
 Q, ■ i 1 ' - ■ ! ' ■ 
 
 
 
 : 
 
 
 . . 1 
 
 1 
 
 
 
 ■' 
 
 
 
 i j . 1 . ; , ' j . : 
 
 . i 
 
 .._, ., 
 
 _4^ _._^_ 
 
 
 
 '■- 
 
 
 
 
 I 4 
 
 
 ■ ■ J 
 
 — : — . , 
 
 
 A" 
 
 /./ 'J , 1 1 1 1 
 
 //, 
 
 ;-^ 
 
 -*—-»- .^-«-' 
 
 \ 
 
 IXTKUNATI 
 
 Diagram shewing i 
 rrom the I'-of Augi 
 
 Diaf^ram shewing vi 
 in Niagara River a 
 

 1 1 ' ■ 
 
 1 ' 
 
 
 
 
 ■ \ ■\ 
 1 
 
 
 . . . . , 1 . , 
 
 1 
 
 
 : 
 
 1 
 
 
 
 
 , , j .... I . 
 
 ; 1 
 
 
 
 , i . ; ! . :. 
 
 
 ■ 
 
 i A • 
 
 1 ■ ■ ■ 
 
 
 ,. , ,.[ . ^ 
 
 
 
 ■ La ■ ■■ 1- 
 
 f^. 
 
 
 ,.'■ s 
 
 
 
 
 t^'-"^^ 
 
 '"•*"'*--^.r -^■"■7 i*. .«3^ 
 
 t';;-2rS '""^ ■ 
 
 ^ ■ ,,. . 
 
 _.,'•-->•' ^s.......^ 
 
 
 Y ^z 
 
 vK 
 
 '' ./ 
 
 ^/-C-V. 
 
 ...'-V'' -'"""■^'•-^-- 
 
 -yv^-'-^-^s^^^^-^^T^ 
 
 — ■ -...- ^ 
 
 ■ ' . ■! ■ -■ . t 
 
 '^'^>-,:^* * "*' 
 
 r 
 
 v,v 
 
 f .■ ' _:_:__^ • :. ■■: 
 
 
 
 
 ■ Y . 1 . 
 
 . . . . j . . , 
 
 
 1 
 
 1 
 1 
 
 
 . . , . j . . 
 
 
 . ^.. ..] . A. . 
 
 
 
 : .-.-i 
 
 1 
 
 
 
 „ 
 
 
 
 \ . ! , . . j . , . . 
 
 
 
 
 t ■ - ■ 
 
 
 ■ ■ ■ 1 
 
 
 
 
 ■ ■ ■ 1 
 
 
 
 ■ ■ 
 
 -• 1 ■ ■ 
 
 
 rr— ]. 
 
 
 
 
 . . . - 
 
 . - . . 1 
 
 1 , ._- 
 
 
 
 
 
 
 : 
 
 
 ■ ■ 
 
 
 
 1';.- 
 
 >^ 
 
 u 
 
 ' ■ ■ ^ ■ ^\ \ \ \ ■ \ ■ '\ ■ i ■ /\ j ■ ■ ; \ -t— • 
 
 .jturr. Li'.; = 
 
 X- 
 
 :*- ---- 
 
 IXTKILWnoXAL ISKIDCIv 
 
 -•_ . i^K 1 ZK .; 
 
 iagram shewing rise and Fall of the Niagara River 
 om the P-' of August 1870 to 1^' of August 1873 
 
 ■ ■!■;•■ I ' . \:> 
 
 '"' '1 
 
 ■ '-'A: 
 
 a^ram shewini^ velocities and directions uf currents 
 Niagara River at international Bridi^e site. 
 
 ■:% 
 
jr 3 
 
 i 
 
 a 
 
 m 
 
 u 
 
 J 
 
 u 
 
 ^ 
 
 3 
 
 a 
 
 HQ 
 
 a 
 
 23 
 
 M 
 
 "A 
 
 m 
 
(a 
 
 m 
 
 3 
 
 <J 
 
 M_J 
 
 ^ 
 
 iii) 
 
 JjJ^- 
 
 1] 
 
 iL 
 
 A. 
 
 t\ 
 
 -a^i^ 
 
 ^ 
 
 ^ 
 
 It I 
 
 "Pi 
 
 
 ",1^ 
 
 / 
 
 
 
 •-^^ 'X" 
 
 IXTKKXATIDNAL IIIIIIH.'K. 
 
 PLAINS OF OUTER CAISSON, 
 
 l!>l'll III llli' 
 
 Erection of Piers N"M.5(^6, 
 
 f If! IjiV-** l.ilhT.rvfi. . 
 '-' a if- tt F*. '' 
 
 " M ^ ^ "JLrt taM «Ji' ^ ^ "f'*' 
 
j^itmrn m m.i^±u i m .¥^.i\ .r i 
 
 
 4'i: - i ^ tj < n n n ! M 1 Ti yfyi i r; 'i r rrri. t 
 
 *- to 
 
 _: B 
 
 I 
 
 y. 
 
 u 
 
 09 
 
 u 
 
 3 
 
 si 
 
 X 
 
 •^ 
 
 x. 
 
 3 3 
 
 r-^^-4 
 
 3 :; 
 
 t.-v.-r-ij:-. 
 
 1- 
 
 h 
 
 h-i 
 
 "^ ' q N a 
 
 -i:^ p.: 
 
 T :- '-■-•1^ 
 
 m 
 
 9- 
 
 I •• ^ • I 
 
 Sl- 
 
 "i' 
 
 a- 
 
 ii 
 
 
 
 
IXTKUXATIONAL IM^IlXilv 
 Method oF Anchoring Outer Caissons. 
 
 
 »^:-*?ii'rin:if>r;i>V5;^^ 
 
 :^'-?.-.^V»\ "?:'.! ;;?/;>■. 
 
 :Vrv^»/;*'''-'- 
 
 \. 
 
 'v 
 
 r"* 
 
 ^! 
 
 ili!^--.::. 
 
 I |! iM 
 
 
 t 
 
 a-. 
 
 ;jtit-i .'- 
 
 \ 
 
 
 rr.■»:■■■:\^^C _■» 
 
 Us!';i-^«'-i.' 
 
 
 r;'^-.'': 
 
 
 •.■^■^.''r i^ V 
 
V\Vr- .'!. 
 
 IKMDCi:. 
 Caissons 
 
 C 
 
 " - ' — - -•'• ■■ 
 
:>'i'- Kl^'Viti ri 
 
 f" — -rar--"^ ■ ■ ' ■ ' . j'-* ' - --.-^^m, 
 
 ■ '■■ ' "-'W*" 
 
 1 -^ ^un;w fc l *ii . uia Mi — 
 
 
 INTKIiNATlONAL HKIDC.K 
 
 •^■mi^^ PLANS HF 
 
 'rv !•' (•J.V |fl>,!l 
 
 
 
 .;l! 
 
 
 .4*::! 
 
 ■ ■ .-I ■ ^ 
 
 \-l!;^ '_ d 1^ ' nil 
 
 
 
 ■ i 
 
 wmimmm^sEm 
 
 ABUTMENT 
 
 ^^■w^jfc'WiiMWjiiiM^ inii't'.T I *! I mill mmm^imm^Hn^ ■■ ' m 'i .jfii i ■ ' ■!■ i — - ■■ ■ ■ *H '* ,'^ V 
 
 
 .i>&'-o: I'l-T -..,. 
 
 
 "111 iWlliii 
 
 :"i ^^.^i 
 
 #Jv^ \h. ^^ 
 
 ' : 
 
 f^ 
 
 ' -■' ' i 
 
 ~ ~~~ 
 
 r~ — '" 
 
 — ,'■- 
 
 -■-.J- 
 
 — fe- 
 
 ^,ir- 
 
 ;•■•• r- 
 
 PiF-i 
 
 vr: ' 
 
 
 R^l 
 
 ': }•■, 
 
 ' 
 
 . • • i 
 
 '■•''' 
 
 
 •. ': 
 
 t "■ 
 
 
 :-;i 
 
 
 -1 
 
 s'4 
 
 in! 
 
 6 i 
 
 .;': r 
 
 S- 5^j! 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . ■" 
 
 
 
 • 
 
 
 
 
 
 ■■- , 
 
 ' A 
 
 
 
 
 ■' - 1 
 
 /• ' ' 
 
 
 
 
 
 ' ". 
 
 
 
 
 
 
 
 
 •v'. 
 
 
 \\> 
 
 
 \" 
 
 .•t 
 
 
 
 '■-. 
 
 ^•^i 
 
 ^^'i 
 
 
 
 ^;- 
 
 :'-i 
 
 '■ .' 1 
 
 ■r 
 
 :- L 
 
 
 I- ■^;S 
 
 ,„|.H!i 
 
 
 
 'la 
 
 
 ■A 
 
 ' - -i I '■ 
 
 'Kf; 
 
 ^•:^!tv^ 
 
 
 \V.j 
 
 ,c, * 
 
 ;vj 1' 
 
 ■.;-.i ^ 
 
 V\ 
 
 ,*»■- 
 
 ;.-.:^! , 
 
 :*' ' 
 
 f,' f 
 
 '* . ' . ' 
 
 
 -i^-aJimi M .iBkyaM^w* lUi" m^^ 
 
 7'-:v \\\;i il . 
 
 P 
 
 ■-.. —.k" -•_». -^ 
 
 -j -.:..:.,L...,..,J,.. ■„ I 
 
 /tmrJi^ttili I II I] 
 
 -^'.< 
 
 -U. 
 
 -I 
 
 Z^ 
 
 'ill' " iT,f.'ii|. '"""iji' J 
 
 V**, ;'.::i^. :;j*| 
 
 q 'J 
 
 J._... 
 
 r 
 
 1 
 
 ?^'& -A.^.^.. 
 '"'■■ '''^^:^ 
 
 
 7^f 
 
 ?^n 
 
 rT 
 
 '-•'■ 
 
 ii'i 
 
 y. 
 
 
 
 
 ':■• 
 
 ;".■ 
 
 t". ■' 
 
 "'',1 
 
 ,• 
 
 ^ ', 
 
 \ 'M 
 
 ',' 
 
 
 t:i: 
 
 
 ', > i 
 
 '.'»/; S't-i! 
 

 ■ssr 
 
 
 
 
 Sf -—if--' =■= 
 
 if 
 
 
 
 A:4 
 
 I .-^m. ^.|i;,- ^ : J^ ..^;^ -t ,^,, .-4--- j*^i.|^ii^ 
 
 
 r-5f»-- = 
 
 :r'le 
 
 
 
 i.V.^'.•.■' 
 
 Pe;.-^' 
 
 
 ■■.KV 
 
 ■J..' 
 
 I I rr-i Ttir - - ■ III! I ' ■■ ■ ■ n ■ 11 ■ " " - ■ - /"-"'- ■•■■■■ I -—'■ - ■ - - - - •''.- --T^-'- JL^..y^ 
 
 
 F]JU 
 
IXTKKXA'l'IONAh 1{|{|I)(;K 
 
 JJ-E j t i PlL I IJ- gfia g u 
 
 '^ 
 
 
 PLANS OF PIER N9 2, 
 
 •t|- 'Ijrl'. i ' I.ith t wr.r.. 
 
 
 r- . J i ■'.»>■ •, » .■;.'• *;'. •■ ■.. . ■ j i , 
 
 
 l-o-i 
 
 F-.. 
 
 I 
 
 / . ^^- 
 
 .'v 
 
 WP'i^afc;-^';a... ! ^T 
 
 I-!r'nzoi;r,.. I 
 
 I ■- ■ r ■■ 
 i'-:- trenkei. 
 
 '■ft. 
 
IXTKKNA'riOXAL IMillXlK 
 
 PLANS OF PIER N? 5 
 
 .11 \\'.:^ .,'.-■.'1 T- I' 
 
 
 t -*V^J| ; .J(l 
 
 HU H lWpjM ^IBfHPPIj^gg" 
 
 i-j- ,i-i-e!.j.^iJ ^wj!g»jsa> 
 
 
 
 •II 
 
 (f--^ 
 
 ■^^-^^.w^ 
 
 iiniifinr**'^~~~iB^"^"T™™"*'*T*™ * i ' 
 
 t 
 
 
 
 
 
 
 
I up .-.'';'-...ir., 
 
 -11 C 
 
 
 !n:i:T:r:riiiixi3:T 
 
 nASniTjCSTDT 
 
 F:^ed Rock. 
 
 
• 11' I* i> ■,•■.!' 1' 
 
 INTKKXA'riOXAL WUWMW. 
 
 PLANS OF PIER N? 6. 
 (Shewing recess for End of draw girder) 
 
 m, , I II I .»i«. i.. . ,.;,«» ., i,... ^. „^ . M l 
 
 * ll||i ii ., i,i. 'm iw. ■! . il ' ■ II ... , l p^, — I ^ »■» 
 
 ^u^^i-m, 
 
 
 
 :si«' 
 
 
 
 •J'i.Vv,';'"!-" n ! 
 
 < •;■ • .», *•^■• 
 
 
 ,■( v-:-i 
 
 rm; 
 
 .-••i J---1 
 

 - ■•, 9 
 
 .■•>3ft 
 
 ^■^W"**^^- ^'^v 
 
 M<»tliod of cUnijinit; and dowelliiig the courst-: 
 Scile '6 mch - 1 Foot 
 
 
1. • 
 
 ■ '1 
 
 4 
 
 J 
 
 
 '' «m ■% %• ! ■ >! . '■< ■ r-i 3>— j(.. . ' . . . '' 
 
 1^ I ■'. f • I. ■ Ji, i ■■■' ll • t J- -J 
 
 ' w 
 
 LMI W Ti 
 
 r%ii '■T'-f- 11 
 
 
 '> 1' 
 
 • t I ■ 
 
 .1 iFirMir 
 
 n ■ 
 
 .'^ 
 
 / 
 
 \ 
 
 INTKltXATIONAl. Ill 
 
 PLAN fJF PIER N°7T0R T 
 
 \ 
 
,i:'ioii 'hi 
 
 "•»';;-y.:.j>..»..-. ■*■:.. J 
 
 » ' '«'*t# i»"'^ r*>* • ' 
 
 '^•,/i'./;»'>';'»"v? 
 
 
 PIMiH 
 
 *-|-vl *;. 
 
 XATIONAI. IIUllMilv 
 
 PIER N'^VTOR TURNTABLE 
 
 \n 
 
 e 
 
 m © 
 
 u 
 
 (?•'.*. Vi'-^. , ■"•.••■.'••■:''^-r,'-H*?1 
 '''.■.'*,.■>■« •• '.■»■•■ •■'•"' "■.».; w 
 ' ■,»U?^'<''»- 'f.iV'v'.'? ■'if:"c;''.l»-1 
 
 >/i'f-.'--^>.-4.-.'^.<;:..-<'/i>1 
 
 
 Q 
 
 
 © 
 
 e 
 
 ® 
 
 
 
 vi^ 
 
 ' '''^ 
 
 @ 
 
 © 
 
 
 © 
 
 >3 
 
 @ 
 
 @ 
 
 © 
 
 © 
 
 v."? 
 
 e 
 
 © 
 
 C) 
 
 ® 
 
 © 
 
 '"*' 
 
 ^^ 
 
 © 
 
 ^\*\^ 
 
 '■tl^v-: 
 
 ■•.^*'"--7!;- 
 
 .<,» -.">• 
 
 
 »• ». ■. • 
 
 
 i'i.V ..":.•.'; 
 
 
 
 K 
 
 
 ..^^/'iv^^ 
 
 
 ■ ■ .■"•'»■'•■<•■■•«.: 
 
 
 ^V'> 
 
 
 
 **&.v 
 
 
 r 
 
 ;.?:;^rt ■;!<?>»;? 
 
 '% 
 
 
 ■*•„ -■■•»•; 
 
 
-1 1' 
 
 l.M'KKX.VnoXAL HI 
 
 |*>-«m4 
 
 ^ 
 
 
 mm 
 
 
 '^' I III! i iii i "t >ii ifapiiiiti w li iT H uMMB ii 'A'' mi l I itl T" . HI I i 
 
 ^ 
 
 i i l i WM t miin- .i. ,' l 3 .,.w y LM . |.i , a . ■, „, , , , ^ 1— .1. Mj , . , '!! . ,' i I i fifljW , . j^j l/ 
 
 yiiii«atfHif i nmi|»- I ii li g .i.w y . L . - fja - iu.. . ^ — I I . ' — I. ui t ^ . r-f . — , i i i l i irAp. . . -»^* 
 
 L- •■ a: •'■■'-ii-Jt-t - - . .iM- ■ - -V^ - "t- -^' , ,- . ,L .;1S„ i S'Wi 
 
 v;v«feji*w- •>4. „:-•;;■■*. -j:*;^, , A . .i> .^.Hiili 3 
 
 H r .W '' f' r"""j1IU '' ^T lip- #•■ ^ ^:'#''''-' # - :5!lir 
 
 r 
 » • ■ 
 
 ■■■I 
 
 ;. . 
 
 m 
 
 
 -.1 
 
 ^1 
 
 ' .1 
 
 ■.i 
 
 ■I 
 
 PLANS OF ABUTM 
 
 m 3 
 
 *uji| "IjiVA' lii'l' Till ■ni".. 
 
 7rz:zr:xz::i:T^:-^^:'^:^'^'^:^Bc:::m 
 
 — <' 
 
 :^ 
 
 
 t! 
 I 
 
 -■sr 
 
 
T; I'-'-ir "I! 
 
 x.vnoxAi, UHincK 
 
 FruM' Pilovdlioi;. 
 
 NS DF ABUTMENT 
 N? 3. 
 
 \iy} ".>iV A . U'liTut 
 
 tlJL::M.;:;|l:^';.^3'i'' 
 
 1 '^y^"'' "■''^"' 
 
 
 iti> iiini I 111* 
 
 
 JimiSfMfl ^ m i pfn s .....A i ' I ' ' i t « i »B|(pB||i|>Mw 
 
 ..>'^s-r^«^•^^' 
 
 
 if;" "'f"- 1 '■{y.-< 
 
 JII.L}:. 
 
 '■ " I' 
 
 •' <. 
 
 •,'.;; ■ ■ 
 
 :ru 
 
 ,•^■3 
 
 1. ,y 
 
 ■■^ 
 
 - <' 
 
 i'. '. 
 
 ■■/■: 
 
 
 ' ~t' 
 
 - .■ 
 
 ! /■■■', 
 
 e ■ 
 
 ' -5 
 
 ■••V 
 
 
 ;.■! 
 
 
 .■* 
 
 J - 
 
 
 '.' 
 
 
 •"•/■ ' 
 
 
 , ' 
 
 ' ' 
 
 ' /i 
 
 
 '. •.( 
 
 .- 'i 
 
 . > - 
 
 \\i 
 
 
 ;, , 
 
 
 \ ■ ' 
 
 1 ^ ' 
 
 
 .•V; ;■; 
 
 .'' ' 1 
 
 •'':i',i 
 
 • ) ' 
 
 
 '; * » 
 
 '"' ' ' i 
 
 '• ') 
 
 I ^ 
 
 •;. ; 
 
 ■■• ; 
 
 Si^ 
 
 k'.-'tl.-'l: ■ 'M I ,l!i" A P 
 
 -.C'titif. o;i 1 uu A 
 
 
 
 !,i:^r. 
 
 
 '>;. .-. 
 
 C "4 
 
 
 
 
 IJ 
 
 HI 
 
 
 
 5^^r- 
 
 
 mm 
 
Tr-insvers<? 3*=: 
 
ILir.-TrXiil. 
 
 EU-v,itii 
 
 n. 
 
 INTEKXATK^NAL HllIl)(iK. 
 
 190 FT GIRDER and DETAILS. 
 
 f<'alf* tbrEWMtlor. htuI Transverse Se^'i- 
 
 J 1.; a* in 
 
 
 1- 
 
 Si-ale for FiP,i-" o tr li mcl-usivB. 
 
 
 
 ,:'• ■,>l.-' '.01 Tn,"'?!. 1 to 4 inclnsiv-f. 
 
 ir 
 
 
 Copp, CUfk * t'y Uth T.Tcnu 
 
Till. X 
 
ElcnMlujii. (MaiTi l-'iv< r [ 
 
 v/^' /^ '^y^- •■y-/,.y/iif^-^//^f/4'^/^-<'-\ 
 
_ j. wij ' t\t;. a. .? ! / , ' r\. r. T : . r- n .i% /n ,fl aitiiiUfflnin'H 
 
 <c 
 
 "«>■*-■ ■ » ■ I IJ f A I UgjJ igBgiBBB Laj i t l lllJtf-Jfe.U I Bgf^^kiyUR i WMMJig^HyMfltM tBi .l^^ 
 
 ^_..l 
 
 PierN" 7 
 
 p'.U'V-^ition ( '"anH; Dnv.'.) 
 
• - , 
 
 -~_1"C 
 
 .-^: 
 
 !i^»-.^. 
 
 <r 
 
 
 1 
 1 
 
 
 
 
 1 
 
 1 
 1 
 
 
 i 
 
 
 ' 
 
 
 
 
 ■ 
 
 .^ 
 
 
 V 
 
 
 
 
 aa-at 
 
 wis 
 
 y/mm 
 
 
 
 
 7 
 
 r- *■ - •■- 
 
 
 
 a 
 
 wr 
 
 .--^«Sw_. 
 
 Vi 
 
 S.Sf.'-^-J^^JfSXJISLS..^^^ 
 
 A-'J'. ii .-Ltjii i mHtJ-a 
 
 Pi-r W^ 
 
 1 L iP MwwM . ■ r'sr T S-^T-" 
 
 mmimtf^mmmmm 
 
 T'i'-rTI'nO 
 
i 
 
 . vv.ia-A-. \ ; ■ i . 1 1 , u ojLUxi. 
 
 INTKIWATIOXAI. IIWIIM.'K. 
 
 PLANS OP TURNTABLE. 
 
 '\A\X| 
 
 ¥ 
 
INTKUNATIONAL HIUlx:!:. 
 
 "METHOD ADOPTED FOR ERI^^HTINC 
 Superstructure over deep wa'.er spans. 
 
 IM' -.\tl 
 
 .<!■- Incr. 
 
 TTT 
 
 \ 
 
 >l A M 
 
 \ 
 
 
 V 
 
 
 \. 
 
 \ 
 
 \ 
 
 1 
 
 1' 
 
 
 ■ t 
 
 
 
 \, 
 
 
 
 \ 
 
 
 
 
 \ 
 
 ■ 
 
 ■ 
 
 / 
 
 ■ / 
 
 «.5-^''"- ■« 
 
 _1i 
 
 ;-... 
 
■'■"\ ... :■;/' 1 
 
 
JiA^raTi :f 
 
 ':^S'.? 
 
 ijij. 
 
 ■in -J 
 
 .'lilil-l'. -:(''!! ',' 
 
 'yj\iv 
 
 r'Yum.'. i h '> - 
 
 /><r/,i /,'■;■ yi i-iiill.\: 
 12 27'/ ///.>■ X/,i//r /,;,,/ nl' Iriixx pi/ /hi////. 
 2(i.('l'(> . /ii<//i//f/ /<!,/,/ nf'Kitfii///' /n /• /i(t//i'/. 
 //I 7,'/0 . I!f////i<i li'inf itl'T/iii/i //rr /ni/i/'/ 
 .'/'.',!> I:'.iin:s- t'I'K/i/u/ic Italic/ />(•/■ f>ii,i/-l 
 
 X." rt' /'<'// //r /A 
 II, //lilt ,)l l'<,,/(L- yfo." 
 
 /,//////// «ir,i////x 12 Id' 
 
 
 '^■■: 
 
 ?a;. ^ \ 
 
 pC 
 
 ^i 
 
 K 
 
 .V I* 
 
 '■* A'.- 
 
 
 
 N*;' 
 
 
 
 ^;^- 
 
 A' ■ V 
 
 / V, 
 
 -^X; 
 
 i>^ 
 
 ,*3cvs 4' . f '->-'',.•"■.«• *^ '.;->' - 
 
 
 '..''iiJ-— ■;■.,>'-. : 
 
 (i< --^ *.'Av:''+'; 
 
 Diav'?rr.un .t fjirvjitir 
 
 ■p'-ins ! i',. 
 
 
 l)/,t<i li<r SI 1(1/ i/s\ 
 
 /('.V.t'7 ///i 
 
 .^'htf//' lf}///l ol' I'/'iiAA i,r//n,,//'l 
 
 A'l'.v' //m: 
 
 luill//i//l<i(/// pr/ /ki/i/'l nl i<iic 'I'/i/xx 
 
 2<i.<hl7 lli-y 
 
 Ihhil liui/l 
 
 
 .v.' iil'p////i/,i- /.'). 
 
 
 H//iflil iir/)ii////.\- 2ti '(>'.' 
 
 
 Li n/flJi nl'imiir/x /2' /(' /". 
 
 , - 19.^ c . 
 
-u-i'-r : va;is 
 
 ■'ptin:-' .. 
 
 i^v^ ;-:vi^ 
 
 
 
 
 
 
 
 
 
 
 . '3 :V 
 
 k 
 
 
 
 
 
 
 
 
 
 
 
 
 
 -\/ 
 
 / 
 
 / 
 "' '4 
 
 \ 
 
 "'V' - 
 
 .>v/ 
 
 p4 -/ 
 
 ^'' vT 
 
 .■■ // 
 
 \ P' 
 
 
 
 #\5 
 
 
 
 
 ^S -J, 
 
 
 >^ 
 
 rj~ 
 
 • \- 
 
 
 #1 
 
 
 
 
 
 
 \c^ .4^ 
 
 5^ ^^^ 
 
 p, 
 
 ■''\*r 
 
 1 
 
 ll'/frin,/ S/rmn.v 
 (hitipmrsu'iiiiii '/i</i ( /lorr/ iir/fl nut fM,\- ■KSl'f Ifw /irr.S<f.ui. 
 (hiiifinwvii'iion Inliriiir l\wl,f ,t. /'/>/> . . 
 
 Tlirxc Imuh hriiitj %"'ol'l)ii- iillinnih' \/rrti(jth lifr/lirfil 
 lh<iii (ivn/diM f(iniiiilti . 
 
 'Iitixioii (III /dMi/ii ('/i(>n/ fi/iif '/iiv l<i.(H'Plb.\:pirS'ii.in> 
 7<ii.ti(>!i oii,S'u,\/)('nxiori /on/i.w 7M> ... 
 
 S'hifirin<i SI rain I'll /'i.>i,\- S.(i(<fl . . , , 
 
 .^iii;': . 'pMna 1 V,. '• ■>• 9. 
 
 Uor/cititf yi rill in 
 
 
 
 ( riii/iirvrifii on '/o/i ( 'h<<rr/ 
 
 Slice /A 
 
 pa Sif. III. 
 
 (oiiiprc.uioii cii /■.'ill/ /'(I.\/a- 
 
 T.'/t' 
 
 ■ , 
 
 ( 'oiiipir.wiofi on /iilirmr /Kt/.c 
 
 ■hi TJ 
 
 
 /i-/i.\-h'ii till /hiI/oiii Hun/ urn/ '/iiW 
 
 /diUH' . 
 
 
 'lcn.vi,iii ,<ii yii.t/></ixliiil /I'ofM' 
 
 y. />(>/' . 
 
 
 Sliciiii iiif Sliiiiii (<ii /'i/i,K- 
 
 XOOP 
 
 
 i 
 

 INTKIiXVnONAL l.MilDCi;. 
 
 PLAN OF TRAVEI4LER USED IN CONSTRUCTION OK PIERS, 
 
 -J 
 
 ii^ai^iiii^>£^d«i;il 
 
 /. \ 
 
 
 
 'M-^^M^^^^fmmp 
 
 1'^-i'.-nfe-f»ac'»; 1 
 

 s=y^^s^ 
 
 "JC 
 
 1:ie? 
 
 Jau 
 
 -1 "^ 
 
 -^•g"' Vj-, j 
 
 ;^-^.:r 
 
 -T^r •>"» 
 
 k-.. 
 
 i^ 
 
 "^^ 
 
 ^6.^X1. 
 
 
 -n-^ 
 
 / 
 
 
 *fl •>» 'i ' 
 
 / 
 
 i^iif 
 
 / VJ_ 
 
 V3y^ 
 
 v. 
 
 "/. 
 
 X, 
 
 
 c , 
 
 
 13 ' 
 
 
 
 
 nS 
 
 
 i 
 
 ^ 
 
 
 < 
 
 -a 
 
 1/] 
 
 13 
 
 Cl, 
 
 S! 
 
 
 
 d: 
 
 
 it: 
 
 
 
 
 ^ 
 
 ■on 
 
 
 c 
 
 < 
 
 
 
 
 1 i 
 
 u 
 
 P- 
 
 1.- 
 .0 
 
 1 
 
 -J 
 
 rq 
 
 1 
 
 'I 
 
 :l 
 
 
 
 :i 
 
 1 
 
 
 
 • 
 
 
 — 
 
 
 — ■•- 
 
 H 
 
 
 
 N 
 
 1 '^ 
 
 ,. r-^ . 
 
 
 I 
 
 -■:?s.' 
 
 i 
 
 ^^1 
 
 ; 3m k 
 
 4 a, .tfc 
 
 -v 
 
 .=< 
 
 ?3- 
 
 J 
 
INTKKXATIOXAL UUmiV 
 
 PLAN OF DREDGING MACHIMERY 
 
 
r ! .1 • ■ vxi 
 
 m 
 
 :iiti 
 
 t-. 
 
 
 yjp -am