gons, with the names of Kelk and Lucas painted upon them, drawn by handsome dray-horses, are bringing in supplies that appear inexhaustible. Foundries, factories, and workshops, in different parts of London, furnish various materials, and these are also continually flowing in. The supply of material, indeed, is one of the wonders of the work, and gives rise to the conclusion that, should there be any delay in the finishing of the Building, it cannot possibly be imputed to any failure in this department. As the respective trades are following up each other as closely as possible, -the carpenter coming quickly upon the bricklayer and smith,the glazier keeping close up to him, and the painter pressing onwards close upon the heels of all,—the labour department on the spot would appear to be quite as removed from the liability of blame, should the ultimate want of punctuality incur any.

"To see 4000 men at work on one building is a sight worthy of contemplation. Among the skilled men in their allotted places at their allotted tasks, with no shirking anywhere and no driving taskmasters to be seen, there is an appearance of personal interest in the progress of the work that makes the spectacle even more telling. Shipwrights, sailors, ship-carpenters, bricklayers, plasterers, house-carpenters, joiners, coppersmiths, ironsmiths, steelworkers, painters, glaziers, labourers of all nations, are employed in honest labour for honest pay at a season of the year that is often characterized by compulsory idleness of many weeks' duration. By division of labour, and sub-division of contracts, each small set of men in the various trades and departments bring about a great result—all are for progress; and there is no coercion."

Probably there never has been raised a building where economy has been brought to bear so rigidly upon construction. There does not appear to be a superfluous ounce in the lofty iron pillars, nor in the great spanning girders, or the light-tied roofs; and the principals are placed at the greatest possible distance apart that is compatible with a likelihood that they will be able to perform the offices required of them. Yet, for the most part, all is considered to be satisfactorily solid.

Some idea of the magnitude of the undertaking so successfully completed by Messrs. Kelk and Lucas might be gathered from the immense mass of materials known as "builders' plant," used in the erection of the Building, including 12,000 scaffold poles, 18,000 cords, 10,000 boards, 6000 putlogs; 1000 loads of timber, used principally for the construction of the great domes; 5 steamengines, 20 tons rope falls, blocks, chains, smith's tools, &c. &c. The whole of this plant was sold by auction shortly after the completion of the Building, and realized about ten thousand pounds.

The strength of the Building had now to be scientifically tested. The following is the Report addressed to the Commissioners of the Exhibition by Mr. W. Fairbairn and Mr. W. Baker, civil engineers, detailing the results of the proofs to which they themselves experimentally submitted the strength of the galleries and staircases. The strength of the domes, it will be seen, is but lightly touched upon :

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"To the Commissioners of the International Exhibition. "My Lords and Gentlemen, -Feeling that it would be a source of satisfaction to the Commissioners, as well as to ourselves, as members of the Building Committee, and also a due precaution for the public safety, that the gallery and other floors of the International Exhibition Building at South Kensington should be thoroughly proved, we undertook a series of experiments on Monday last.

"We have to report that, in carrying out these experiments, the various floors and stairs were put to a more severe test than they would be subjected to with the largest number of people that could possibly be assembled upon them at any other time during the Exhibition. The results of these experiments fully bear out our calculations on the strength of the different parts of the structure, and we feel perfectly satisfied as to the stability of the Building for the purpose for which it was intended.

"The two large domes, in the strength of which we have taken great interest, were eased from their temporary support last week, and no observable settlement took place.

"The following are the particulars of the tests :-We first caused a large body of men, about 400 in number, to be closely packed upon a space 25 feet by 25 feet on one lay of flooring; we then moved them in step, and afterwards made them run over the different galleries, and down each staircase; at the same time we caused the deflections of the girders carrying these floors to be carefully noted at several places, and had the satisfaction of finding that, in each case the deflections were very nearly the same, thus exhibiting a remarkable uniformity in the construction. The castiron girders, with 25 feet bearings, deflected only one-eighth of an inch at the centre, and the timber-trussed beams of the same bearing placed between these girders deflected half an inch at the centre. In every instance the girders and trusses recovered their original position immediately on the removal of the load. "We are, my Lords and Gentlemen, yours faithfully, "WM. FAIRBAIRN, Į "WILLIAM BAKER, S

"London, Feb. 13."

C.E.

THE EXHIBITION BUILDING DESCRIBED. The main Building occupies about sixteen acres of ground: it is nearly rectangular in shape, and measures about 1200 feet from east to west, by 560 feet from north to south. It lies south of the Horticultural Society's Gardens and the Kensington-road. The Cromwell-road forms the southern boundary; on the east it is shut in by the Exhibition-road; and on the west by Prince Albert's-road. ' The whole of this ground is covered by permanent buildings; and two long strips of ground, east and west of the gardens, were roofed in by the temporary sheds, or annexes, in which were shown machinery,

D

and large and heavy objects. This additional area extends to

seven acres.

The interior space is entirely covered in by roofs of various heights, and is divided into nave, transepts, aisles, and open courts: the latter are roofed with glass, as in 1851, but the other parts have opaque roofs, and are lighted by clerestory windows.

We shall now describe the respective fronts of the Building. The South Front, in Cromwell-road, 1150 feet long and 55 feet high in the brickwork, has two projecting towers at each end, rising 16 feet above the general outline, and a larger tower in the centre, in which latter is the main entrance to the Picture Galleries; being about as long as the Gallery of the Louvre, in Paris. The exterior is chiefly brickwork, relieved with semi-circular-headed panels, separated by pilasters, and between the arches are circular niches; in the lower portion of each panel being a window, to admit light and air to the ground-floor, and to ventilate the Picture Gallery above. The panels are plastered in cement, and it is proposed to ornament them with English mosaics, dependent on the funds. This great frontage has almost unanimously been condemned as ugly and featureless; but Captain Fowke designs to incrust it with terra-cotta panels enriching the great pilasters and other parts of the face, the present blank window spaces being filled in from end to end with a grand series of designs in solid mosaics, rich in colour, emblematic of art and science, and other works." The Editor of the Practical Mechanics' Journal objects that the lower or glazed portion of the windows of this front, as now framed with timber lintels visible en face, and cast-iron perforated ventilators in them, can never be made to look well or to harmonize with any finished remainder. The windows must be solid carved stone or terra-cotta jambs and mullions, with arch or other headings of like material, and showing deep reveals, and perhaps projecting balconies, if ever this (at best awkward) appropriation of the whole arched height between the pilasters is to satisfy the eye of taste. Again, were all this done, it may be said, the site makes it useless; the opposite houses preclude our seeing the front of the Building except in sinall bits at a time. Quite true; but the architect did not make the site, it was dictated to him, and as we ourselves strongly surmise, with this in view, that should the Building become a national gallery, the houses at the south side of Cromwell-road should be purchased out, and a sufficient open space in front be thus ultimately obtained.

The East and West Fronts, though differing from the South, are not less imposing. They are, in all respects, similar to each other in their general aspect. Here the huge domes, rising to a height of 260 feet, show to most advantage, and the transeptroof, with its lofty clerestory windows, is in full view. To the observer below the form of each dome appears nearly that of a semicircle: this effect is obtained by making its height 11 feet

Two of these mosaics are already executed.

more than its semi-diameter, which fully allows for the loss by perspective diminution.

From the crown of each dome rises the pinnacle to the height of 55 feet. Each dome is in the middle of each façade; its centre is the point formed by the intersection of the centre lines of the nave and transept, and the front of the Building is advanced from it 108 feet. Under each noble arched recess is the main entrance to the Industrial Courts, the effect of which forms one of the most pleasing exterior parts of the Building

Each of the porches contains a deep semicircular arched recess, 68 feet span and 80 feet high, in the tympan of which is the great rose-window, visible from end to end within. The window is one closing the vista as the spectator looks from a standing point beneath the other.

At the extreme north and south are two auxiliary picture-galleries, each 247 feet long. The main and auxiliary picture-galleries afford available wall-space covered by pictures, equal to 7600 square yards, or about one and a half acres.

The only portions of the Building which resemble the Crystal Palace of 1851 are the six courts north and south of the nave : they have glass roofs on the ridge-and-valley plan, supported by square iron columns and wrought-iron trellis-girders. As these courts are open from floor to the roof, they admit floods of light into the Building, with admirable effect.

The construction of the East and West Domes was a hardly contested labour: in fact, there was a battle of the domes," and the victory was won by the eastern one.

The construction of the two Domes, and the whole of the roofing of the courts, was intrusted to the Thames Ironwork and Ship-building Company; the making and erection being placed under the superintendence of Mr. T. E. Hussey, an engineer of experience. He selected Mr. J. Mauldin (one of the sub-contractors for the erection of the transept and two towers of the Crystal Palace, under the inspection of Mr. Cochrane), to whom the erection of the two domes and the roofing of the courts were sublet. Mauldin hoisted the first column of the eastern dome on Monday, October the 21st, 1861; the first column of the western dome, Wednesday, November 13th, 1861; making three weeks and two days between the start of the two domes. Messrs. Kelk and Lucas then offered their assistance in erecting the western dome, which was accepted. From this time commenced the battle of the domes. The western staff showed great spirit in putting up large wooden ribs, of which the eastern staff could not see the utility. This staff still kept their steady and safe course, while the western tried all they could to overtake them by employing nearly one-third more men, and working till a late hour in the night, with the assistance of gas, the eastern men leaving work at the end of the day. The number of derricks rigged for hoisting and fixing the ground ribs for the eastern dome were nineteen. The whole of the main ribs of the eastern dome were hoisted and fixed by thirteen pairs of shear legs and thirteen derricks. The number of derricks rigged for hoisting the ground ribs in the western dome was twenty-eight. The number of shear-legs for hoisting the main-ribs was thirteen pairs, and twenty-six derricks : although this extra tackle and number of men were employed, yet they could not gain on the eastern dome. When the western found they could not gain the advantage they left off their nightly labour, and followed the eastern at a greater distance than when they started. The cost of labour for erecting the western dome was over 10007. sterling more than the cost of the eastern. There still was an extra cost for tackling. The scaffold resembled forests of timber: they occupied nearly the whole interior space of the domes, and were cross-legged

and cross-bolted, to enable them to bear the weight of the iron, 120 tons in each. The building of the scaffold occupied eight weeks, and every beam was hoisted by the steam-winch: very little of the timber was spoiled by cutting, and each scaffold contained 40,672 cubic feet of wood.

The plan of the groined roof-ribs of the domes, it must be allowed, is ingenious and novel. Each dome is at the intersection of the nave and transepts.

The dome-scaffolds were stated to have been upon a greater scale than anything of the kind ever executed. To this the Editor of the Practical Mechanics' Journal demurs as follows:-"To go no further, we imagine that the centering with which the tremendous concave of the central brick dome of the Baths of Caracalla at Rome must have been turned, probably involved more timber than the two dome scaffolds made into one. However, these scaffolds were most admirable examples of skilful combination, with great economy as to the injury done to the timber, nearly all of which was in whole or half bulk."

The two duodecagonal domes, 160 feet in diameter, and 250 feet high, are officially described as the largest of ancient and modern times.* The dome of the Pantheon is 142 feet in diameter and 70 feet high; the dome in the Baths of Caracalla was 111 feet; Brunelleschi's, at Florence, is 139 feet in diameter and 133 feet high; the dome of St. Peter's is 158 feet in diameter, and 263 feet high from the external plinth; the dome of St. Paul's Cathedral is 112 feet in diameter, and 215 feet high. The domes are of glass, with an outer and inner gallery; and it has been proposed to erect one of Messrs. Chance's dioptric lights at the top of one of them, and to illuminate it at night.

The effect of the domes is thus described in the official Concise History. "The Exhibition Charter provides that fifty thousand pounds shall be spent in the architectural completion of the central portion of the Building out of the contingent profits. The two great domes being each 300 feet from the south front, can never in any way enter into its effect. If the middle hall, with its great central dome, should ever be built, then the Cromwell-road front will not be without this ornament. Each dome keeps its place, as the centre of its own front, and its effect is utterly independent of its fellow, which is 1000 feet from it. The upper terrace of the Horticultural Gardens is the only point from which the two present domes appear simultaneously; and when thus viewed, so completely does the Building carry on the symmetrical lines of arcades and terraces, that the duality of the domes is at once accepted as the natural complement of the system which has governed the laying-out of the entire quadrangle."

*This is denied in the Practical Mechanics' Journal. The dome of the old Halle au Blé, at Paris, of timber, was 200 feet diameter; and after its destruction by fire was replaced by the wrought-iron and zinc dome, still in existence, of the same dimensions. There has been also this misconception as regards these domes. They have been compared with those of St Peter's and St. Paul's, which they exceed in size; but they do not rise to so great a height as either of the cathedral domes. The Exhibition domes rise 264 feet from the ground; St. Peter's, 434 feet; and St. Paul's, 340 feet.