« ElőzőTovább »
in Spain, and in other countries of Europe, had qualified him for the task, was enabled at an early stage in the progress of the building, to foresee the effect of the combination in perspective of its various lines. Serious apprehensions were at first entertained as to the propriety of the application of colour, usually devoted to the decoration of extended surfaces, to what were asserted to be lines only. Mr. Jones was, however, enabled to estimate how far the merging in distance of those lines would give them the appearance of surfaces, and the three tints of blue, red, and yellow have been distributed by him over the columns and girders, so that as the surfaces blended in perspective, each column has allied itself in colour with its fellow column, each vertical face of girder with the vertical faces of its fellow girders, and each soffite, or underside, with its fellow soffites. Breadth and distinctness were given to the enunciation of each colour. The light of the sky appearing through the interstices of the roof, the principal portions of which have been tinted of a delicate blue, unites with the colour, giving it at once air and brilliancy. The effect of this mode of treatment has been to add considerably to the apparent elevation of the building. By varying the colours of the vertical and of the horizontal lines, and retaining each uniformly, the eye is enabled to detect, at even the greatest distance, the direction and position of every part of the construction, and thus the otherwise endless confusion of the complexity of lines, is reduced to order and simplicity.
Although a provision for the gratification of the intellectual tastes of the the refreshment visitor has been the main object in the formation of the Exhibition Building, ministering to his more ordinary appetites has not been lost sight of. Commodious refreshment rooms, with the accompaniments usually connected with them at large railway stations, have been provided around the trees at the northern extremity of the transept, and adjoining open courts towards the eastern and western extremities of the buildings, where the presence of the trees dictated their location.
The official business connected with the conduct of the Exhibition rendered The oHi«*. necessary the employment of a large staff of clerks, &c, for whom, and for the juries, &c, a considerable extent of accommodation has been provided in offices placed on each side of the southern entrance.
We have supposed our visitor to enter on the south side; admittance may, The entrance*
. , , ... ., , and exits.
however, be also gained at the eastern and western ends, where similar vestibules, 72 feet by 48 feet, afford accommodation for turnstiles, check-takers, &c. Disposed at nearly equal distances from one another, on the four sides of the structure, are 15 exits, by passing through either of which the building may be quitted.
In issuing from its precincts the visitor will pass through the gates of an iron The exterior or
... . . . tile building.
railing designed by Mr. Owen Jones. Retreating to some distance, he will be enabled to take in a general impression of the whole building, as shown in fig. 16. From the north-west angle the most picturesque view is to be obtained, and from that position may be best appreciated the grand effect produced by Mr. Paxton's happy idea of raising the semi-cylindrical vault of the transept roof, above the tiers of terraces which extend on either side of it. For much of the grace of proportion and beauty of form, which from this point of view the visitor cannot fail to notice, the building is indebted to Mr. Barry. Upon the form and distribution of the arches and filling-in frames, as well as of the columns, the suggestions of that gentleman exercised a happy influence.
M£* u»''ofr,n ^n ^o- 17 we have given a view of a bay of the building, 8 feet in width; elevation. an(J from that and the other illustrations a tolerably correct idea may be formed of
the nature of its external construction. The spaces en- At the east and west ends considerable spaces have been enclosed, for the
closed at eastern *
and western ends. purpose of affording accommodation for large objects, the weight or dimensions of which precluded their admittance into the building.
The boiier-tiouae. At about 155 feet from the north-west angle, a structure, 96 feet by 24 feet, has been erected for the purpose of containing the boilers for generating steam, to be supplied to give motion to the various machines requiring to be exhibited
The water supply.
Conclusion of Part I. of subject a—" The
1'uil dine as it stands.'
Commencement of Part II. - •• Its creation."
Arrangements sulfsequently to acceptance of tender.
in operation. The external appearance of this building precisely corresponds with that of a portion of the main edifice of similar dimensions. It contains five boilers, equal to 150-horse power, and a large tank, serving as a balance-head to the watersupply. This supply consists of a 6-inch main, entirely surrounding the building; upon it, at intervals of about 240 feet, are placed fire-cocks; and at different points in its circuit 16 4-inch branch-pipes enter the building, and lead so far into the interior, that fire-cocks placed upon their ends are so situated that circles of 120 feet radius drawn from each of them would intersect one another. The mains running on the north and south sides of the building are connected across the transept by a 5-inch main, from which, near the centre of the building, pipes diverge, leading east and west, for the supply of the various fountains placed upon the central line of the nave.
Having endeavoured to convey some general idea of the nature of the building as it at present stands, it may be desirable to trace the successive steps by which it has grown into the form it now assumes.
When it is remembered that the tender for its construction was not accepted by the Royal Commissioners until the 26th of July, 1850, that possession of the site was only obtained on the 30th of the same month, and that the first column was fixed on the 26th of September, it will be manifest that into the intervening period must have been crowded arrangements, which, under ordinary circumstances, would have required at least double that period for their completion. Details of construction had to be settled, elaborate calculations as to the strength and proportions of the several constituent parts to be made, machines for economising labour to be devised, contracts for the supply of materials to be entered into, and thousands of hands set actually to work. How unintermitting since that period the labour must have been is testified by the fact, that the opening of the Exhibition takes place on the 1st of May, the day originally appointed.
On the ground being given up to the contractors, the first work undertaken hm^?« cop- was the construction of a hoarding to inclose the whole area of the site. This being given uP to
It r ■ • ■ r contractor*.
hoarding was formed by the insertion into the ground, in pairs, of the timbers ultimately to be used as joists. Between each pair of uprights were slipped the ends of boards, ultimately to be used as floor-boards; and these were secured by attaching together the two ends of the joists extending above them. Thus the expense of the hire of waste boarding was avoided; the timber composing the hoarding was completely uninjured; and the celerity with which the whole area was surrounded was truly remarkable.
The task of setting out the plan of the building was intrusted to Mr. BROUNGER; The letting out, and the extreme accuracy with which the situation of every column was fixed, and the adjustment of every level was performed, reflects credit upon that gentleman.
In order that the measurement of 24 feet, upon which the accuracy of"?»proceeded the whole plan depended, might be indicated with extreme precision, poles of thoroughly-seasoned pine were fitted with gun-metal cheeks, or small projecting plates, the ends of the poles extending a few inches beyond the cheeks. The measurements were taken by laying one pole on the other, so that the inner edges of the gun-metal cheeks, set at precisely 24 feet from one another, might be brought into contact. Thus the danger of any error, arising from the ends of the poles becoming damaged in use, was avoided. Stakes having been driven into the ground to indicate approximately the position of the columns, their precise centres were ascertained by the use of the theodolite, and marked by driving a nail into each stake at the exact point. When it became necessary to remove these stakes, in order to dig out holes for the concrete foundations, an ingenious method was resorted to, for at any time identifying the position occupied by the nail which had been removed. To effect this a right-angled triangle was framed in deal, at the two ends of which saw-cuts were made. Previous to the removal of the stake, the apex of the triangle was set to the nail indicating the situation of the centre of the column. Two other stakes were then driven beneath the saw-cuts, and two nails driven in at the ends of the saw-cuts. The wooden triangle being then removed, the centre stake was withdrawn, the hole made, and the concrete thrown in. The height of the surface of the mortar, varying with almost every column, was regulated by pegs driven to the correct level under the direction of Mr. Brounger. Another triangle of a somewhat similar character to, and having saw-cuts in the same position as, the one already described, having two of its angles adjusted to the two stakes remaining in the ground, determined the exact position in which the base-plates had to be fixed.
As every casting was delivered on the ground, it received a careful examina- c»«ting«extion, and an immediate coat of paint. The girders, upon the perfect soundness ^rd"TM provedof which the stability of the galleries and roof mainly depended, were subjected to a rigorous test, in a machine arranged for the purpose by Mr. Cuarles Heard Wild. One of Mr. Henderson's patent cranes was so placed, that, on a waggon containing girders being brought beneath its range, a girder was lifted from the waggon, and deposited upon a weighing apparatus. An account having been taken of its weight, the girder was again lifted by the crane, and carried forward to an extremely strong frame, the two ends of which corresponded in form and dimensions to the connecting pieces with their projections. The girder being securely confined in these clutches, a force was exerted upon it at the two points upon which the weight of the floors and roofing would have to be carried, that is
to say, immediately over its vertical lines. The force thus communicated was applied by two pistons, forced upwards by a modification of Bramah's hydraulic press; the principle of which, it will be remembered, depends upon the power gained by forcing water (by means of a small piston) into a strong cylinder in which a larger piston works; the power being increased in the proportion borne by the area of the piston to be raised to the area of the small piston. A registering apparatus affixed to the pipe leading from the force-pump to the testing-machine, afforded the means of adjusting the pressure exercised by the hydraulic press. A careful observation of this apparatus conveyed the assurance, that every girder, according to its ultimate destination, was proved to a strain of either 9, 15, or 22 tons. After testing, the girder was released from its confinement, again raised by the crane, and stacked in a convenient place ready for removal. So admirably were the various arrangements made for conducting these operations, that it was possible for a girder to be lifted from its waggon, weighed, secured in the testing-machine, proved, released, again raised, and finally deposited, in less than four minutes.
In order to elevate the columns to their places, what is known in technical language as a pair of shear-legs was employed. This simple apparatus consists of two poles lashed together at their heads, and maintained in a steady position by ropes extending, from the apex of the triangle formed by the base-line of the ground, and the inclination of the poles, to one another, to stakes driven into the ground at a considerable distance. From the apex of the triangle a series of ropes passing over pulleys were suspended perpendicularly; and, by means of this " fall," the majority of the columns, girders, and other heavy portions of the construction, were elevated to their places. The operation of raising girders is shown in the
view, fig. 18, but on so small a scale as to convey only an imperfect idea of its detail. Modifications of the simple apparatus described sufficed to hoist almost every part of the necessary iron-work. A connecting-piece was attached to each column previous to its elevation; and so soon as two columns with their connectingpieces were fixed, a girder was run up, slipped between the projections of the connecting-pieces, and secured in its place. An opposite pair of columns having been similarly elevated, another girder was attached to them; and thus two sides of a square were formed, and maintained in a vertical posi
tion by poles acting as supports to them. Two other girders being then hoisted, mi fl,cj and slipped between the connecting-pieces on the remaining two sides of the square, a perfect table was constructed. The "shores" or supports were then removed, together with the shear-legs, and the whole apparatus was at liberty, for the purpose of recommencing a similar operation in an adjoining 24-feet bay.
When a sufficient number of these bays had been completed, starting from the The ■mmd«nd
•* .... third itone* com
intersection of the nave and transept, to warrant the addition, the hoisting of the menoed without
1' . ■emuOttUng—how.
columns for the first floor was commenced; more lofty shear-legs being of course employed. The extension of the ground-floor structure proceeding, as that of the first floor was carried on, a base was in turn afforded for the columns of the third tier; and thus the iron frame work of the whole building rose from the ground, firm and secure, without involving the necessity of any scaffolding whatever.
While these operations of actual structure were being carried on, under the The p»p«i«on
T • i #■ ■»«- T n i i i- • of the other work
immediate superintendence of Mr. John Cochrane, the work of preparation was yet more vigorously pushed. The manufacture of the Paxton gutters, and the application of machinery to their formation, is so interesting, as to warrant a somewhat lengthened notice.
In the year 1837, when Mr. Paxton commenced the construction of the The Rutter
rn J ....... lii- luJung machine
Lhatsworth conservatory, in which similar gutters were employed, machinery had not been brought to bear upon their construction. By the use of a contrivance, the details of which were arranged by Mr. Cowper, a gentleman in the employment of Messrs. Fox and Henderson, a total length of upwards of 2,000 feet per day has been turned out, for many successive days. The pieces of timber destined to form the gutters are sawn into lengths of 24 feet, 6 inches deep, and 5 inches thick. Three of these pieces are fixed on the frame of a planing-machine, and by it arc worke ctraeand square. In figures 19, 20, 21, and 22 are given representations of the details of the gutter-making machine, erected at Messrs. Fox and Henderson's workshops, near the Thames, at Chelsea. Fig. 19 is a side view of a block of cast-iron, to which Fig.19.
steel cutters (AAAA) are attached by bolts and nuts (BBBB). Four blocks, of similar construction, are fixed to four spindles, and by the action of drums on the same spindles, set in motion by bands moved by a steam-engine of 20-horse power, the blocks are made to revolve with extreme rapidity. Any piece of timber exposed to the action of these cutters, must obviously be scooped out into the form of the outline of the cutters attached to each block. By modifying
the form of the cutters almost any variety of section can be given to the timbers brought into contact with them. In the present case, the four sections A, B, C, and D (fig. 21), represent the successive action of the four sets of cutters lettered to correspond with them (on fig. 20), by means of which the larger cavity for the rain water, and the two smaller channels for the condensed water, are formed. The part removed by each set of cutters is shown by the hatched lines.
Fig. 22 represents a plan of the machine, looking down from above upon the gutters, the gutter being removed in order to show the action of the cutters more clearly.
The operation may be explained as follows:—The piece of timber, properly Its mode of squared, is placed upon the roller marked E, it is then pushed on until it comes "**"