Chapter IV: Part 4

Next to the setting out of the positions of the columns, perhaps the operation of fixing the base-pieces was that in which the greatest accuracy was required; for as there were in some parts three storeys of columns to be fixed over them, any inaccuracy as to their level or position would be very much increased at the top of the building. To fix the base-pieces over the centres that had been determined for the columns, another carpenter's square was made use of, like that already described, but having the right-angled corner cut out to the form of the section of a column. This square being placed with the notches in its short sides over the two stakes already described, the upright portion of the base-piece was fitted into the notch at the angle; and as the reader will at once see, if he has followed us in the description of the various processes, its correct position was thus exactly found.

In order to determine the level of the top of the base-pieces, boning-sticks were placed in the lines of the columns, and when the base-piece had been approximately fixed, a piece of wood was placed on it edgeways, the top of which was to range with the top of the boning-sticks. This was easily arranged by looking along them; and the workmen drove down the base-piece with a wooden mallet till the desired level was obtained.

From what has been previously stated, it may be gathered that the base-pieces had to be fixed truly upright in one direction, but slightly inclined in the other; and to effect this a plumb-rule was made, on which the deviation from the perpendicular line was marked; and this, when applied to those faces of the base-pieces which were to incline, served to show when the proper inclination was arrived at, whilst an ordinary plumb-rule applied to the other upright faces tested their vertical position.

The first column was raised on the ground on the 26th of September, but little more than two months after the tender had been accepted. In the meantime, many of the different castings had already arrived on the ground, and a considerable advance had been made in the carpenter's work for the gutters and other parts. The semi-circular ribs for the transept roof were also being put together, and stacked in such a manner as not to stand in the way of the other works.

We may mention here that every casting, as it came on to the ground, was weighed and registered, and every girder proved, as already described; in doing which considerable assistance was derived from one of Mr. Henderson's patent Derrick cranes, which was erected near the proving-apparatus. By its means a girder was raised from the waggon in which it arrived, placed on the weighing-machine, weighed, removed to the proving-press, tested, raised again, and deposited on the ground in a stack, in less than four minutes.

Henderson's Derrick Crane.

A brief description of this useful engine may not be out of place here. It consists of an upright mast (E), steadied when the crane is in use by two sloping stays (F F). These stays are fixed into horizontal timbers (G) on the ground, connected with the foundation-plate (H) on which the mast turns. At the foot of the mast is fixed a combination of wheels and working handles for raising the weight, technically called a crab. A beam (A) working at the bottom in a socket (B, Fig. 3) fixed to the foot of the mast, but hanging out from it in a sloping direction, is called the DERRICK, and forms the principal peculiarity of the crane, as it can be raised more to the upright line, or lowered to slope more outwards, as may be desired, by means of the chain (C). The advantage of this is obvious; for a weight may thus be raised from or deposited at any point within a circle of a certain radius, depending on the length of the derrick; whereas, in an ordinary crane, the weight can only be placed at points upon the circumference of that circle. The whole engine revolves on a pivot (H, Fig. 2) at the foot of the mast. Cranes of this description are made varying in power from one to forty tons, and with derricks ranging from twenty to sixty feet radius.

Raising and Fixing the Columns and Girders.

Many of the persons who visited the building during the progress of its erection were heard to inquire "where was the scaffolding;" and others even imagined that the skeleton framework they saw was, in fact, only the scaffolding for the building, and not parts of its actual construction. This leads us to point out one of the most interesting peculiarities of the structure; namely, that it formed, as it were, the scaffolding for its own erection. In order to raise the columns upon the base-pieces, two poles were placed upright, connected by a horizontal piece, forming what is called shear-legs; the whole being steadied in its position by ropes from the summit fixed to the ground in various directions. A rope with pulleys fixed to the horizontal piece served to hoist the column, and sustain it in a vertical position until the bolts were passed through the projecting rings at the bottom of the column and the corresponding ones at the top of the base-piece, and screwed up. When two columns had been thus fixed, a connecting-piece was attached to each end of a girder, and the whole raised by the same apparatus, and fixed on the top of the columns; bolts being passed through the holes in the projections of the connecting-pieces, corresponding with those on the top of the columns. The shear-legs were then moved on twenty-four feet to perform the same duties to another pair of columns; and two sides of a 24-feet bay were thus formed. To complete the square, two more girders were raised in a similar manner, and fixed between the connecting-pieces over the columns. The square bay then became a firm structure, requiring no further support; and by repeating these operations all the smaller avenues of the building were erected, of the different heights of one, two, or three storeys. The greatest number of columns thus fixed in one week was 310.

Hoisting the Roof Trusses.

The wrought-iron roof-trusses over the 48-feet avenues were raised in a similar manner to the columns and girders; and in all cases horses were employed to run out the end of the fall-rope, which was passed through a pulley or catch-block at the foot of the shear-legs, in order to change its direction from vertical to horizontal.

For raising the roof-trusses of seventy-two feet span over the main avenue a somewhat different method was employed. A single mast or derrick, more than seventy feet high, was placed in the centre of the avenue, and steadied in an upright position by guide-ropes spreading from the top in various directions. Near its summit the hoisting-tackle was firmly lashed on. The trusses to be hoisted were brought from the places where they had been put together, and placed across the main avenue at the points where they were to be fixed. Two ends of a stout chain were passed round the upper portion of the truss, at points dividing its length into about three equal parts. To this chain the hoisting-tackle was attached, guide-ropes being further fastened to each end of the truss to steady it in its ascent. In order to stiffen the truss horizontally, struts were attached at the centre projecting on each side, and held in their place by tie-rods attached to the upper part of the truss, and forming a triangle on each side. Before the truss, therefore, could bend in a horizontal direction, the attachment of these tie-rods must have given way. Six horses drew out the end of the fall-rope, and in the course of a very few minutes the truss was hoisted to its giddy height, and each end slipped in between the projections made in the connecting-pieces to receive it.

The animated scene presented by these operations was highly interesting from the number of men employed, both on the ground and for fixing the trusses in their position aloft, and from the rapid progress so many hands made. Each gang of men was managed by a foreman, who was obliged to issue his orders through a speaking-trumpet, to enable his voice to be heard in the din caused by the other works going on around. Besides the two large gangs of men engaged in the hoisting of the trusses, other smaller gangs were at work at different points getting up the columns and girders. In one part, the roofing of which was completed as early as practicable, a crowd of carpenters were preparing the Paxton's gutters and other portions of the work. In another place, as soon as a sufficient space could be roofed over and a temporary floor laid, various parts of the machinery we have already described were fitted up and worked by portable steam-engines. Of these there were three in different parts: one drove the machinery for finishing the sash-bars, gutters, ridges, &c.; another worked the drilling, punching, and other machinery connected with the iron-work; and a third was used for working circular saws.

Of the number of trusses that were hoisted as above described, in only one instance (and that the first) was the result otherwise than perfectly successful. The first truss was raised by its ends, instead of from the centre; but that method was afterwards abandoned, from the difficulty of maintaining the truss in an upright position during its ascent; which was important, as, if it turned on its side, its lateral strength was not sufficient to prevent it from bending, which would have destroyed the joints of the work.

One of the tall masts was worked on each side of the transept, from the centre to the ends of the building, being maintained constantly in an upright position, while traversing from point to point, by alternate slackening and hauling up of the ropes which steadied it; and it was curious to witness the motion of these tall giants, as they slowly progressed from one point to another, in the performance of their important office. Stout planks were laid along the ground, upon which the foot of the mast was forced forward by crowbars and levers; the planks served also to distribute the weight, which would otherwise have sunk the end into the ground. As many as seven trusses were hoisted in one day by each derrick, which had therefore to travel a distance of 168 feet.

So careful were the men, under the direction of the manager (to whom was intrusted the active superintendence of the whole erection of the building), that no accident of importance occurred in these difficult operations.

Provision for Expansion of Girders.

In connexion with the fixing of the girders, it may be desirable to mention the provision that was made for the expansion and contraction of the iron, which in so great a length as that of the building might have otherwise produced results prejudicial to its stability.

Between the projections cast on to the connecting-pieces and those projecting from the ends of the girders which they were made to clip, sufficient space was left for the introduction of oak keys, by driving in which the girder was fixed in its place, whilst the compressibility of the wood left sufficient play for the expansion of the metal. In describing the girders, it was mentioned that in the upper and lower flat flanges small sinkings were cast near the ends. Corresponding with these sinkings, a notch was left in the projection which came out from the connecting-piece; and when the girder was put into its place, iron wedges were driven in between the notch and the sinking, by which means any lateral motion of the girder was prevented. It was a great advantage to have the means of fixing the girders of so simple a nature, as any arrangement presenting the least complication, or requiring great nicety, would have materially retarded the progress of the work.

The wrought-iron trusses were held by the connecting-pieces in a similar manner to the cast-iron girders; but, as an additional security, bolts were passed through holes provided in the standards at the ends, and through the connecting-pieces, where they were screwed up with nuts.

The raising and fixing of the extra-strong roof-trusses crossing the main avenue near the side of the transept required particular care, from their great weight; the heaviest being, as we have before mentioned, no less than eight tons. These trusses were the first that were fixed across the central avenue, and about 150 men were engaged in the hoisting of each one. They are secured to the columns by four strong bolts passing through the end-standards.

In order to provide additional support for the great weight brought upon the last-mentioned trusses by the transept roof, extra columns were introduced underneath them. These were built up in storeys corresponding with those of the other columns, with which they were connected, at the levels of the girders, by bolts and straps. A cast-iron shoe, fixed on the top of the columns, provided a bearing for the ends of the truss. The columns just described project slightly into the main avenue from the line of the other columns; and this is the only instance in the interior of the building of the iron columns occurring at a less distance than twenty-four feet apart.

Glazing the Roof.

We have now traced the erection of the building up to the level of the roof, in which it will be readily conceived the operation of glazing was one of extreme difficulty, there being no scaffolding to aid the workmen in conducting their operations. When the glazing was first commenced a light scaffolding was suspended from the rafters; but this was found to be too tedious and troublesome a method of proceeding for so large an extent of roofing. It was, moreover, of great importance that some means should be devised for completing this part of the construction independently of the weather; a matter of some moment, when it is remembered that the work had to be done in the winter, when in our climate such operations are liable to be very much impeded by heavy rain. The arrangements made to meet this difficulty, as well as some others for carrying on the works, are very clearly described in a paper by Mr. Digby Wyatt, read at the Institution of Civil Engineers, on the 14th January, 1851, from which we quote some passages, by permission, for the benefit of our readers.

With reference to the means employed for glazing the roof he says: "To effect this purpose, a travelling stage was devised by Mr. Fox, which superseded the necessity of any scaffolding for glazing, and by means of seventy-six of these machines nearly the whole of the work has been executed. The stage was about eight feet square, and rested on four small wheels travelling in the Paxton's gutters. It thus embraced a width of one bay of eight feet of the roof, with one ridge and two sloping sides. Each bay in width required, therefore, a separate stage."

"Each stage was occupied by two workmen, and was covered by an awning of canvass stretched over hoops, to protect them in bad weather, and was further provided with a box on each side to contain a supply of glass. The sash-bars and other materials were piled upon the stage itself, the centre of the platform being left open for the convenience of hoisting up materials, for which purpose there was a small iron arm with a single block pulley."

"Whilst working, the men sat at one end of the platform (the ridge having been previously fixed in position by means of the extra-strong sash-bars), and they fixed the glass in front of them, pushing the stage backwards as they completed each pane. On coming to the strong sash-bars previously fixed, they temporarily removed them to allow the stage to pass. In this manner each stage travelled, uninterruptedly, from the transept to the east and west ends of the building, and the glaziers were enabled to follow up the previously-fixed work very closely. The average amount of glazing done by one man per day was fifty-eight squares, or about 200 superficial feet; and the largest amount done by any one man in a working-day was 108 squares, or 367 superficial feet."

The mode of fixing the squares of glass was this: a sash-bar having been nailed down between the ridge and the gutter, the workman inserted one long edge of a square of glass into the groove in the sash-bar, he then placed a loose bar against the other long edge of the glass and brought the whole down to bear upon the ridge and gutter, the second sash-bar fitting into the notches prepared for it; the glass was then pressed up a little, in order to insert its upper edge into the groove in the ridge, and the workman then filled in the grooves on the outside of the glass with putty, the lower edge of the glass having been also bedded on putty where it bears on the edge of the gutter. The ends of each sash-bar were fixed with a nail driven into the holes previously drilled.

Stage for Repairing Glass.

As it might naturally be expected that out of the thousands of panes of glass employed, particularly in the flat roof of the building, many would be broken in the course of the works, subsequently to their being fixed, it was necessary that a ready means should be devised for repairing any such damage, as the glazing-waggons used for the first execution of the work would not be available for that purpose. A light stage was therefore constructed, travelling with wooden wheels upon the ridges instead of in the gutters; and from this the men were able to perform their work without walking along the narrow gutters, which would have been attended with much risk. This stage was also used for fixing the canvass on the outside of the roofing, where it is nailed along the ridges, and allowed to bag down slightly between them. The object of the canvass, which covers externally the whole of the roof except the transept, is twofold: it preserves the glass from damage, and also protects the objects exhibited from the direct rays of the sun, which would, of course, in many instances, be very prejudicial; for the latter purpose the upright sashes on the south side are also covered with canvass on the inside.

Hoisting the Ribs for Transept Roof.

One of the most interesting operations which attracted the attention of the numerous visitors to the works was the raising the ribs for the semicircular roof of the transept, the description of which we give from Mr. Wyatt's paper:--

"The operation about which most anxiety had been felt was the hoisting of the arched ribs of the transept. These ribs were constructed on the ground horizontally, and when completed with all their bolts, two of them were reared on end, and maintained in a vertical position, at a distance of twenty-four feet from each other, by guy-ropes. As the ribs singly possessed little lateral stiffness, they were framed together in pairs with the purlins, intermediate small ribs and diagonal tie-rods, forming a complete bay of the roof twenty-four feet long; two complete sets of temporary ties were also introduced to provide for the strains incident to the variations in position of the ribs during the hoisting. The feet of the ribs were bolted on to a stout piece of timber, and the lower purlins strutted up from the same." In this state the framework is shown in the engraving.

"The whole framework was then moved on rollers to the centre of the square formed by the intersection of the transept and the main avenue, where it was afterwards hoisted. All the ribs were landed over this square, and were afterwards moved on a tramway formed of a half baulk of timber constructed over the columns on either side of the transept, at a height of about four feet above the lead-flat. The hoisting-tackle consisted of four crabs, each one being placed on the side of the transept opposite to the part of the ribs to be lifted by it, so that the men at the crabs might watch the effect of their exertions with greater convenience."

"The hoisting-shears were placed on the lead-flat immediately over the deep trusses of seventy-two feet span; each set consisted of three stout scaffold-poles, lashed together at the top, and footed on planks laid across the flat, and secured by the necessary guy-ropes. The hoisting-rope passed from each of the crabs across the transept horizontally, to a leading block attached to the foot of the opposite angle column of the square; it then passed up to a treble block fastened to the shears on the flat, and from thence down to a double block secured by chains to the bottom part of the ribs."

"There was a peculiar difficulty to be overcome in this operation, which arose from the circumstance that the width of the framework was greater than that of the transept, the extreme width of the framework to be hoisted being seventy-four feet, and the clear width apart of the trusses above which it had to be hoisted being only seventy-one feet four inches. It was therefore necessary to raise one side to a height of thirty-five feet before raising the other, so as to diminish the horizontal width of the whole, the diameter of the semicircle being maintained at this angle; the whole was then hoisted, until the highest end could clear the tramway."

This accounts for the slanting position in which the ribs are shown in the view given.

"The foot of the ribs on one side was then passed over the tramway sufficiently to allow the other side to clear the opposite truss; after which the whole was hoisted to the full height, and rested on rollers of hard wood placed between the sills attached to the framework and the tramway, by means of which it was moved to its permanent position. There it was again raised by another set of shears, while the sill and tramway were removed from under it; and the ribs were then lowered into the sockets prepared for them, formed by the continuation of the columns above the level of the lead-flat."

"Each successive pair of ribs was fixed at a distance of twenty-four feet, or one bay from the preceding one; and the purlins, &c., were fixed in the intervening space without any scaffolding from the ground, by means of jointed ladders, which were adjusted to the form of the roof."

The first pair of ribs was hoisted December 4th, and the eighth pair on December 12th. The operation, which was one of great excitement and considerable anxiety, was personally superintended by the contractors, aided by their most able foremen and assistants; and a crowd of visitors, including many of the illustrious promoters of the undertaking, watched with intense interest the steady ascent of the apparently unwieldy piece of construction, and every spectator seemed astonished at the mechanical regularity with which the whole operation proceeded. It took about one hour to raise a pair from the ground to the level of the lead-flat, and the whole was done without any accident whatever. About sixty men were employed in the hoisting, there being eleven men to each crab, and the remainder on the lead-flats.

Glazing the Transept Roof.

The semicircular form of the transept roof rendered it necessary to adopt a different mode of operation for glazing it to that used in the horizontal portion. A stage, thirty-two feet long and about three feet wide, with a protecting rail at the side, was constructed, so that it rested upon rollers, travelling on the ridges. It was slung by ropes from the crown of the arched roof, and could be raised and lowered at pleasure. It accommodated eight workmen, with the necessary quantity of materials in sash-bars and glass; and they thus performed, with ease and rapidity, an operation which before the fitting-up of the stage appeared at least extremely difficult, and to the uninitiated next to impossible.

The men commenced fixing the glass at the bottom or springing of the arch, and as they completed their work the stage was raised at intervals by labourers stationed on the lead-flat. A portion of the glazing at the crown of the arch was effected by men working on a light scaffold, suspended within from the temporary ties mentioned as having been attached to the ribs; whilst those upon the stage worked upwards till they joined the portion done from the top.

The Painting.

A portion of the work which necessarily occupied a very large amount of time was the painting, which was necessary for the preservation of all the parts, as well as for their appearance; and when it is considered that every portion required to be gone over four times, it must be evident that it was highly desirable to adopt some means for facilitating the operation. It was found that the sash-bars of the roof, being in short lengths and of small dimensions, could readily be operated upon by some mechanical contrivance.

A wooden trough was made sufficiently long to receive the sash-bars, and this was filled with paint; a number of the bars were then put into it, and upon being taken out separately, they were passed through a frame into which a set of brushes were fixed in such a manner as to clear off all the unnecessary paint. Two small brushes, placed where the bar first entered the frame, cleared out the grooves. One workman pushed the bar in at one end of the frame, which was about two feet six inches long, and another drew it out at the other end, where a trough was placed to receive any droppings of paint. The bars were then stacked upright, until they were sufficiently dry for the next coat. The first coat only was put on by this apparatus, the second being done in the ordinary manner, and the last not till after the work was all fixed in its place. By means of this apparatus a workman could perform at least ten times the amount of work done in the ordinary way.

The finishing the painting of the various parts of the roof internally, after they had been put together, was very ingeniously managed, so that while the workmen were able to work with ease to themselves, the scaffolding on which they stood required no supports from the ground, where they would have been much in the way of other operations; loops of wrought-iron were hooked on to the roof-trusses, and by means of these a perfect cloud of scaffold-boards was suspended, enabling between 400 and 500 men to be at work at one time. The roof of the main avenue, particularly, presented a very singular appearance, as nearly one half of the entire length was thus covered at one time, and a crowd of painters were at work over the heads of many, perhaps unconscious exhibitors, who were arranging their goods undisturbed below.

The Hand-rail Machine.

One of the mechanical contrivances which were put up on the ground during the works, for saving labour and increasing the rapidity of production, remains to be mentioned; it was contrived for turning out the rounded mahogany hand-rail for the gallery railing as well as that for the staircases.

The mahogany being supplied in slabs of the requisite thickness, these were first cut up by circular saws into pieces of a square section, and the angles of these were then bevelled off by the same means; the lengths were afterwards transferred to the hand-rail cutting machine to be rounded.

The principal portion of the machine consists of a hollow cast-iron cylinder, round which a strap may be passed to drive it. At one end of this cylinder four cutters are fixed, so that a piece of wood passing between them and through the cylinder, as it revolves, is rounded off to a true circular form of section, and is turned out so smoothly finished as to require scarcely any further work upon it before fixing. In advance of the cutters pressure-rollers are placed, furnished with teeth; and these, as they are turned round by a cranked handle, seize upon a piece of mahogany and force it forward against the cutters, which form, as it were, the jaws of the hollow cylinder, which thus seems to be constantly swallowing lengths of rough mahogany, which escape from it finished. The wooden rail is passed up to the cutters along a groove, the end of which is shown in the small engraving; and opposite each end of the revolving cylinder springs are fixed, which prevent the rail from shifting its position. The hand-rail was all turned out in 21-feet lengths, of which about thirty were completed in the day.

General View of the Works.

We have mentioned that the actual commencement of the building was made by fixing one of the columns on the 26th of September; and, within a few weeks, more than a thousand men were at work, though, from the great extent of the ground they were spread over, it was difficult to estimate their number, which was, however, made apparent by the rapidity with which the building began to grow. The place presented an animated and interesting scene, which attracted a great number of visitors; and crowds of the fair sex were not deterred by the rough state of the ground from endeavouring to satisfy their proverbial thirst for knowledge. In one part of the ground might be seen the putting together of the wrought-iron roof-girders to the deafening tune of more than a hundred hammers; in another place gutters were being put together by the mile, for which some hundred or two of sawyers were cutting up ship-loads of timber. Three portable steam-engines in various parts were driving the different machinery already described, which, however, was mostly grouped in one place near the transept. The central avenue formed, of course, the great thoroughfare, where teams of horses were constantly passing, dragging the slender columns, or unwieldy-looking girders, to their places, while other teams were engaged in running them up to their final position. Over-head, too, the glaziers' waggons, dotted about the roof, seemed to be running on some new aerial railways; in every direction that the eye turned the busy scene extended.

For carrying on these extensive works an immense number of men were necessarily employed on the spot, besides those occupied in preparing the various parts at different places. The greatest number of men on the ground in any one week was 2,260; and the season of the year frequently rendered it necessary for the workmen to continue their labours after dark, which they did partly by the light of huge bonfires of shavings and odd scraps of wood. The effect of these great fires, which were generally lighted in some part of the main avenue, was exceedingly grand. The light of the tall flames was reflected from the glass of the roof far away into the darkness which concealed all the other parts; whilst occasionally a lantern carried by a workman engaged in fixing the upper columns, or some part of the roof, glimmered like some new star.

On one occasion, when the greatest efforts were being made to push on the progress of the works, no less than twelve large bonfires lighted the men at their midnight toil; and had the building been formed of combustible materials, a passing observer would have imagined that the whole was in flames.

Paying the Workmen.

The process of distributing their wages among so large a number of men, on every recurring Saturday evening, was one which could only be effected within a reasonable time by some systematic arrangement; and to such perfection was this brought in the course of the works, that the whole number of 2,000 men or upwards were sometimes paid in little more than an hour; though at first it occupied a considerably longer time.

The mode in which this was effected was as follows:--When a workman was engaged his name was entered in a book against a certain number, which was stamped on several brass tickets, three of which were given to each workman before leaving the ground in the evening.

Every man had to enter the premises three times in the course of the day; namely, the first thing in the morning, after returning from breakfast, and after returning from dinner. On each occasion he was required to deposit at the gate one of these tickets, which were afterwards sorted by the clerks, and entered in the time-book. In this way, if a man failed to come to his work, his ticket would be missing, and the time during which he was absent would not be entered; a corresponding amount being deducted from his week's wages.

On the Saturday, each man's time was made up from the book; and his wages calculated accordingly, and the amount entered against his name. The money due to each man was then counted out and placed in a small tin box, with a ticket, on which was written the man's name and number, and the amount of wages paid to him.

All this was done in the time-keeper's office, which was conveniently placed near the entrance to the works. When all the preliminary arrangements had been completed, the workmen's bell was rung, and they assembled (a motley and sometimes clamorous crowd) round the pay-office, which was provided with two small openings through which the payments were made.

Two men stationed outside the office then called over the numbers of the workmen, who presented themselves, in the order in which they were called, at the pay-windows, where each man took the small box passed out to him with the money, and left the box in passing out at the gate. If any man considered the amount of wages paid to him not correct, he presented the ticket given to him with the wages at the office on the Monday morning following, when the matter was arranged by the time-keeper.

Any person acquainted with the irregular habits of vast numbers of our workmen, who will often be absent from their work a quarter of a day, and at other times a whole day, thus varying the amount of wages due at the end of the week to almost every man, will at once see that, without a well-arranged system, such as that described, the payment of so large a body of men would have occupied as many days as it really did hours. The engravings annexed, in illustration of this part of our subject, will convey to the reader some idea of the scene we have endeavoured to describe, though it must fall far short of the picturesque reality.

General Statistics.

It is with great pleasure that we are able to mention that, notwithstanding the difficult character of some of the work, and the extreme rapidity with which it was carried on, very few accidents of importance occurred; a circumstance which must be ascribed to the great care taken by the contractors for the safety of the men while engaged in their work: and in the cases where the accidents that occurred were of a serious or fatal kind, their origin was mostly to be traced to a neglect of those precautions which the men were constantly urged and ordered to take.

A few statistics of the quantities of different parts of the work not already mentioned will complete this portion of our subject. The whole amount of iron-work in the building is stated at about 4000 tons; and about 1,200 loads of timber were required for the wood-work. There are 2,941 trussed gutters in the roof, and 1,495 glazed sashes were required to inclose the sides of the building. As many as 316 iron girders were cast, in one week, and 442 lengths of the Paxton's gutters were cut out by the machinery in the same time. No less than 18,392 squares of glass, containing 62,508 feet superficial, or about one-and-a-half acres, were also fixed in one week.

It may be further mentioned that the weight of the different parts forming the flat ridge-and-furrow roofing amounts to three-and-a-quarter pounds per foot superficial, on the whole surface; the weight of the arched roof of the transept, including the ribs, amounts to five-and-three-quarter pounds per superficial foot; and the timbers and boards of the gallery floor weigh eight-and-a-half pounds to the superficial foot: from these data the actual weight on the different girders may be calculated.

The light iron-work, with the exception of some of the gallery railing, was cast at the works of the contractors near Birmingham; and the remainder, including the columns, girders, &c., was distributed between their own foundry, and those of the Messrs. Cochrane, of Wood Side, and Mr. Jobson, of Holly Hall, both near Dudley. The wrought-iron was supplied by Messrs. Fothergill, and the timber by Messrs. Dowson and Co.

The Parti-coloured Painting.

The coloured decoration introduced in finishing the painting of the building is a subject which has been much discussed, and many suggestions have been made by persons generally received as authorities on the subject. The system adopted was proposed by Mr. Owen Jones, under whose active superintendence it has been carried out. That gentleman explained his reasons for its adoption, and the effect which he expected it to produce, in a lecture at the Institute of British Architects, on the 16th of December, 1850, some portions of which are submitted to our readers:--

"It is not necessary for me to describe the building, the painting of which we are now about to discuss, as it is well known to most of you by its marvellous dimensions, the simplicity of its construction, and the advantage which has been taken of the power which the repetition of simple forms will give in producing grandeur of effect; and I wish now to show that this grandeur may be still further enhanced by a system of colouring which, by marking distinctly every line in the building, will increase the height, the length, and the bulk.

"The very nature of the material of which this building is mainly constructed, viz., iron, requires that it should be painted. On what principle shall we do this? Should we be justified in adopting a simple tint of white or stone colour, the usual method of painting iron? Now, it must be borne in mind that this building will be covered on the south side, and over the whole of the roof, with canvass, so that there can be but little light and shade. The myriads of similar lines, therefore, of which the building is composed, falling one before the other, would lose all distinctness, and form, in fact, one dull cloud overhanging the Exhibition.

"A line of columns (as it may be seen even now at the building) would present the effect of a white wall, and it would be impossible, in the distance, to distinguish one column from another. This mode of painting would have the further disadvantage of rendering the building totally unconnected with the various objects it is to contain.

"May the building be painted of a dark colour, like the roofs of some of our railway-stations? This, equally with the white method, would present one mass of indistinctness; the relief of the cast-iron would disappear, and each column and girder would present to the eye but a flat silhouette.

"Let us now consider the building as painted with some pale neutral tint, dull green or buff. In doing this we should be perfectly safe, as, provided the colours were not too pale so as to be indistinct, or too dark so as sensibly to affect the eye, we could hardly make a mistake. Yet how tame and monotonous would be the result! It would be necessary that this tint, whichever we might choose, should be of a very subdued neutral character, in order to avoid the difficulty well known to mounters of drawings and painters of picture-galleries, viz., that in proportion as you incline to any particular shade of colour, so in that exact proportion you injure or destroy those objects it is intended to relieve which may have similar colour. To this, then, we should be reduced--a dull monotonous colour without character. How unworthy this would be of the great occasion! How little would it impress the public! How little would it teach the artist! It would be to cut instead of patiently to unravel the knot.

"We are now brought to the consideration of the only other well-defined system which presents itself, namely, parti-colouring. This, I conceive, if successfully worked out, would bring the building and its contents into perfect harmony, and it would fitly carry out one of the objects for which this Exhibition was formed, namely, that of promoting the union of the fine-arts with manufactures. It would be an experiment on an immense scale, which, if successful, would tend to dispel the prejudices of those whose eyes are yet unformed to colour, to develope the imperfect appreciations of others, and to save this country from the reproach which foreign visitors, more educated in this particular than ourselves, would not fail to make were the building otherwise painted; it would everywhere bring out the construction of the building, which, as I said before, would also appear higher, longer, and more solid."

Mr. Jones then adduced the practice of the ancient and mediæval artists, and explained the kind of colours they generally adopted, mentioning that in the best periods of art the primary colours were chiefly or exclusively used.

"In the decoration of the Exhibition building I therefore propose to use the colours blue, red, and yellow, in such relative quantities as to neutralise or destroy each other; thus no one colour will be dominant or fatiguing to the eye, and all the objects exhibited will assist, and be assisted by, the colours of the building itself.

"In house-decoration we occasionally find a run on one colour; thus we have a green room, a pink room, and a red room; but it would obviously be unwise to adopt any one colour for this building, whose contents will be of all imaginable hues from white to black. Discarding, on the other hand, the perfect neutral white as unfit for the occasion, we naturally adopt the colours blue, red, and yellow, in or near the neutral proportions of eight, five, and three; but to avoid any harsh antagonism of the primary colours when in contact, or any undesired complementary secondaries arising from the immediate proximity of the primaries, I propose, in all cases, to interpose a line of white between them, which will soften them and give them their true value.

"As one of the objects of decorating a building is to increase the effect of light and shade, the best means of using blue, red, and yellow is to place blue, which retires, on the concave surfaces; yellow, which advances, on the convex; and red, the colour of the middle distance, on the horizontal planes; and the neutral white on the vertical planes.

"Following out this principle on the building in question, we have red for the under-side of the girders, yellow on the round portions of the columns, and blue in the hollow parts of the capitals.

"Now, it is necessary not only to put the several colours in the right places, but also to use them in their due proportions to each other.

"Mr. Field, in his admirable works on colour, has shown by direct experiment that white light consists of blue, red, and yellow, neutralising each other in the proportions of eight, five, and three. It will readily be seen, that the nearer we can arrive at this state of neutrality the more harmonious and light-giving will a building become; and an examination of the most perfect specimens of harmonious colouring of the ancients will show that this proportion has generally obtained among them; that is to say, broadly, there has been as much blue as the yellow and red put together, the light and the shade balancing each other.

"Of course, we cannot in decorating buildings always command the exact proportions of coloured surface which we require; but the balance of colours can always be obtained by a change in the colours themselves. Thus, if the surfaces to be coloured should give too much yellow, we should make the red more crimson and the blue more purple; that is, we should take the yellow out of them. So, if we had too much blue, we should make the yellow more orange, and the red more scarlet.

"A practised eye will as readily do this as a musician can tune a musical instrument; it is here that science abandons the artist, who must trust to his own perceptions, cultivated by renewed trials and repeated failures."

In concluding, Mr. Jones said, with reference to some specimens of the proposed decoration which had been executed, "I would ask you to banish from your minds the glare of light by which this decoration is now seen--to forget the rough foreground, where men are engaged in every variety of occupation for the completion of this great building; and I would ask you to fill it in imagination with the gorgeous products of every clime. I would ask you to picture to yourselves in the foreground the brilliant primaries, blue, red, and yellow--the rich secondaries, purple, amber, and green, moulded in forms of every conceivable diversity; and, lastly, against them the darker tertiaries fading into neutral perspective.

"The conception of such an effect, difficult even to the artist accustomed to abstract his attention from present interruptions and to calculate future harmonies, is impossible to the uninstructed spectator, who, from the experimental decoration of a single column, draws a premature and, necessarily, a fallacious inference as to the collective effect of the whole.

"From my brother architects I hope for a more patient, a more comprehensive, and a fairer appreciation; for myself, I have a confident hope, grounded on the experience of years devoted to this particular branch of art, that the principles and plans I have had the honour to propose to the Royal Commission, for the decoration of this magnificent structure, will be found, when complete, not to disappoint the public expectations, or to prove wholly unworthy of the great occasion."

In this lecture, Mr. Owen Jones asked his hearers, and the public generally, to suspend their final judgment upon his system of colouring until the whole should be completed, and the building filled with the objects to be exhibited, as he considered that many of the objections which were raised to his proposition resulted from a want of consideration of the ultimate effect to be produced by the whole, when completed and occupied; and so far as this effect has been realised, we believe it has inclined the public opinion more in favour of the coloured decoration than originally, when it was undoubtedly very strongly commented upon in various quarters. Without venturing to express any opinion ourselves, we may trust that Mr. Owen Jones's fondest hopes will be fully realised.

The Water Supply.

The supply of water necessary both for the protection of this enormous building from fire, and for the use of fountains and machinery to be exhibited, is furnished at a very liberal rate by the Chelsea Waterworks' Company. It is brought into the building by a 9-inch main pipe, at about the centre of its length, branching out into three 6-inch pipes, which extend throughout the whole length of the building. Short pipes branch off from these, terminating in fire-cocks, placed at such distances that a circle of 120-feet radius from any one of them will touch a similar circle described round the adjacent ones; by which means the whole extent of the building may be brought under the action of hose attached to each of the fire-cocks. The water is supplied at a pressure equal to a column of about seventy feet, so as to work the fountains that will be exhibited, and to play efficiently from hose in case of any accident by fire. The quantity which the Company have undertaken to supply is 300,000 gallons a day.

The Stability of the Building.

The subject of the strength and stability of the building is one on which considerable anxiety has been felt, both by the public at large and by those professional bodies more capable of forming a correct judgment upon it. In the prolonged discussion which followed the reading of Mr. Wyatt's paper at the Institution of Civil Engineers, many points of objection were raised which seemed at first sight of a very serious nature; but, in most cases, the answers that were given to them were perfectly satisfactory. The two greatest difficulties raised were, firstly, the enormous surface presented by the exterior to the pressure of the wind, with apparently but a slight power of resistance; and, secondly, the construction of the galleries, which, it was thought, would not be able to resist the vibratory motion likely to be produced by great numbers of people walking upon them. The results of several calculations were adduced on the occasion alluded to in support of the objections on the first point; but perhaps the best answer that could be given to them was the circumstance mentioned by Mr. Fox--that on the 5th of that month (January) the pressure of the wind, which blew a perfect gale, was not only much above the average, but very nearly reached the greatest amount known within a considerable period in London--about 25lbs. per square foot; and that as the building, although in an incomplete state, had resisted that pressure without receiving any injury, it was fair to conclude that, when finished, it would be able to sustain the greatest force which the wind could be reasonably expected to exert upon it.

The question of the strength of the galleries was one of even greater importance than the other, as, in case of any failure in that part of the building, human life must almost inevitably have been sacrificed to a great extent. It was therefore deemed necessary to ascertain, as far as was practicable, by experiment, that their strength was abundantly sufficient; and in Mr. Wyatt's paper, as printed, the following description of the experiments instituted for this purpose will be found.

Testing the Galleries.

In the interval between the reading of this paper and its going to press a series of experiments have been tried to ascertain the action of these galleries under the strain of a moving load. A complete bay, twenty-four feet square, was constructed, raised slightly from the ground, consisting of the four cast-iron girders, with the connecting-pieces at the angles, and on this the timbers and boards of the flooring. Rows of planks the full width of the platform led up to it and down from it, so that a body of men as wide as the gallery might be able to march up and down in close rank.

"The area of the platform was first covered over with labourers packed as closely together as possible; but no action of walking, running, or jumping that 300 men could perform did any injury whatever to it, and the greatest deflection of the girders did not exceed a quarter of an inch. Soldiers of the corps of Royal Sappers and Miners were then substituted for the contractors' men; and although the perfect regularity of their step in marking time sharply appeared a remarkably severe test, a minute examination of the construction after the completion of the experiments showed that no damage whatever had been done by their evolutions.

"But as the Commissioners were deeply impressed with the necessity of thoroughly convincing the public, who should visit the Exhibition, that they might feel perfectly secure in every part of the building, it was deemed desirable to apply a still further test to the actual galleries as they stand; as it might perhaps be said that the single bay which had been experimented upon was not similarly circumstanced to those forming parts of the building.

"For this purpose a very ingenious apparatus was devised by the late Mr. Field, President of the Institution of Civil Engineers, for testing the stability of the galleries _in situ_, and on being applied over the greater part of the building not a single bolt or girder gave way under its action. This apparatus consisted of eight square wooden frames divided into thirty-six compartments, each just capable of containing and allowing to rotate a 68-pounder shot. The surfaces of the balls placed in each of these compartments came in contact with the gallery floor, the frames themselves being attached to one another and running along the floor by means of castors fixed at the angles; the whole apparatus being drawn along by a number of men. Two hundred and eighty-eight 68-pound shot confined in a limited area were thus set rolling over more than half the extent of the galleries; when, not the slightest mishap having occurred, the experiment was considered decisive, and a persistence in it deemed unnecessary."