GROUND PLAN OF THE BUILDING COMMITTEE'S DESIGN.1. Machinery in Motion.2. Other Machinery.3. Seats for Visitors.4. Refreshment Courts.5. Raw Materials.6. Manufactures.7. Sculpture and the Plastic Arts.8. Small Court.09. The Rotunda.10. Principal Entrance andExecutive Offices.11. The Other Entrances.12. The Drive in the Park.13. The Kensington Road.14. The Queen's Private Road.
1. Machinery in Motion.2. Other Machinery.3. Seats for Visitors.4. Refreshment Courts.5. Raw Materials.6. Manufactures.7. Sculpture and the Plastic Arts.8. Small Court.09. The Rotunda.10. Principal Entrance andExecutive Offices.11. The Other Entrances.12. The Drive in the Park.13. The Kensington Road.14. The Queen's Private Road.
An objection might, perhaps, be raised to this part of the building, that it was too commodious, and that there might be some danger of its being converted into a lounge, while it was occupying too much of the space intended for the Exhibition, for a secondary, though certainly necessary purpose; it was, however, considered by the Committee, that of the vast number of visitors that might be expected to be in the building at one time, so many would avail themselves of the accommodation provided as to render a less amount undesirable. The principal courts were surrounded by a covered way, where refreshments were also to be served at long counters, in the manner of the railway-stations.
All these arrangements will readily be understood by a reference to the plan of the design we have been describing, which plan, together with a view taken from the south-east angle of the building, will place before the reader the result of the labours of the Committee. The materials proposed for the construction of this building were fire-proof throughout, with the exception of the floor and its supporting timbers.
The above design, at least in all its leading features, for some of the details were subsequently added, was laid before the Royal Commission, at the same time with the Report already quoted, and was by them approved, and the Committee proceeded to prepare the necessary working-drawings and specifications for the execution of the work. These proceedings of the Committee occupied until the 24th of June, when large lithographed copies of the most important of the drawings, together with printed copies of the specifications and other details, were issued from the offices of the Executive, contractors having been some time previously invited by public advertisement to send in tenders for the execution of either a part or the whole of the work. The tenders were to be on two systems, one on the supposition that the Royal Commission were to become thebona fidepurchasers of the building; the other, that the contractors were to erect and maintain the building during the time of the Exhibition, after which they were to remove it and take back the materials at their own risk, receiving a proportionably diminished sum.
It has been considered necessary to describe thus minutely the labours of the Committee and the design in which they resulted, in order to show how far it paved the way for that which was subsequently adopted, and to give them that credit which they undoubtedly deserve for devoting so much of their valuable time for the furtherance of a great public undertaking.
Opposition to this Design.
THE design of the Building Committee, when published to the world, met with anything but public approbation; some of the objectors called in question the practicability of the execution of the enormous dome, at least within the time assigned; others complained that the outlay would be unnecessarily large for a purpose avowedly temporary, and expressed their fears that so costly a structure once erected, there would be the less probability of its subsequent removal; but the objection which appeared to have most weight with the public at large was, the great amount of solid brick construction in the walls, &c., which, it was urged, would require a longer time than could be allowed for their erection, and that the carting of the materials would cause serious injury in the Park and the surrounding neighbourhood. This strong current of objection seemed to bid fair to overwhelm the much-abused design. To increase the difficulties which seemed to gather round the progress of this noble undertaking, an exceedingly vexatious and factious agitation was got up in opposition to the proposed site in Hyde Park, and petitions and counter-petitions were presented to both Houses of Parliament, and much of the time of the Legislature was wasted in fruitless discussion on the subject. The Building Committee thought it desirable, under these circumstances, to lay before the public their reasons for recommending the site in the Park, and therefore issued a memorandum of the grounds on which it had been selected.[2]The result was, that the opposition was defeated in the Legislature, and finally crushed by the force of public opinion.
The Tenders.
IN the mean time the competing contractors had been obliged to strain every nerve to get their tenders ready by the 10th of July, when, altogether, nineteen were sent in, but eight only were for undertaking the whole of the work; the amounts of these are stated to have ranged between 150,000l.and 120,000l., and this for the use only of the materials for the building. But, at the same time, in accordance with the recommendation and invitation contained in the last part of the Report already quoted, Messrs. Fox, Henderson and Co. presented a tender upon a design entirely different in construction and appearance, though resembling that of the Committee in the general arrangement of the plan.
Exterior View of the Building Committee's DesignExterior View of the Building Committee's Design
Exterior View of the Building Committee's Design
Exterior View of the Building Committee's Design
This design was by Mr. Joseph Paxton, and resembled in its general form the building as it is now executed, with the exception of the transept and semicircular roof, which were subsequently added, and were suggested by Mr. Barry.
The result of the tenders appears to have been unfavourable to the Committee's design; and in their Report to the Royal Commission on the subject, made a few days afterwards, they proposed to omit the great dome and some portions of the design which were not essential, by which they considered that the cost of its execution might be reduced below 100,000l.; at the same time, they made special mention of Mr. Paxton's design, which, however, they considered would prove more expensive.
Mr. Paxton's design had been brought before the public before this period; for, considering that his best road to success would be to get a favourable verdict from that many-headed jury, he published a view and description of it in theIllustrated News, and, through the influence of Mr. Stephenson, he got his plans laid before the Royal Commission, in consequence of which he obtained an interview with his Royal Highness the President. The encouragement given him by the attention bestowed upon his design by the Royal Commission, and the favourable opinion of the public, had determined him to procure a tender for the execution of the work, to be sent in with those upon the Committee's design. This he was enabled to do by the great energy and promptitude of the contractors, Messrs. Fox and Henderson, to whom he applied at the eleventh hour. The difficulties that had to be overcome, owing to the shortness of the time remaining for the estimates to be made up, can scarcely be better laid before the reader than they have been by an able writer in "Household Words:"—
"It was now Saturday, and only a few days more were allowed for receiving tenders. Yet before an approximate estimate of expense could be formed, the great glass-manufacturers and iron-masters of the north had to be consulted. This happened to bedies mirabilisthe third; for it was the identical Saturday on which the Sunday postal question had reached its crisis, and there was to be no delivery the next day! But in a country of electric telegraphs, and of indomitable energy, time and difficulties are annihilated; and it is not the least of the marvels wrought in connexion with the great edifice that, by aid of railway-parcels and the electric telegraph, not only did all the gentlemen summoned out of Warwickshire and Staffordshire appear on Monday morning at Messrs. Fox and Henderson's office, in Spring Gardens, London, to contribute their several estimates to the tender for the whole, but within a week the contractors had prepared every detailed working-drawing, and had calculated the cost of every pound of iron, of every inch of wood, and of every pane of glass.
"There is no one circumstance in the history of the manufacturing enterprise of the English nation which places in so strong a light as thisits boundless resources in materials, to say nothing of the arithmetical skill in computing at what cost and in how short a time those materials could be converted to a special purpose. What was done in those few days? Two parties in London, relying on the accuracy and good faith of certain iron-masters, glass-workers in the provinces, and of one master-carpenter in London, bound themselves for a certain sum of money, and in the course of some four months, to cover eighteen acres of ground with a building upwards of a third of a mile long, and some four hundred and fifty feet broad. In order to do this, the glass-maker promised to supply, in the required time, nine hundred thousand square feet of glass (weighing more than four hundred tons), in separate panes, and these the largest that ever were made of sheet glass; each being forty-nine inches long. The iron-master passed his word in like manner to cast in due time three thousand three hundred iron columns, varying from fourteen feet and a half to twenty feet in length: thirty-four miles of guttering-tube, to join every individual column together under the ground; two thousand two hundred and twenty-four girders (but some of these are of wrought iron); besides eleven hundred and twenty-eight bearers for supporting galleries. The carpenter undertook to get ready within the specified period two hundred and fiveMILESof sash-bar, flooring for an area of thirty-three millions of cubic feet, besides enormous quantities of wooden walling, louvre-work, and partition.[3]
"It is not till we reflect on the vast sums of money involved in transactions of this magnitude that we can form even a slight notion of the great, almost ruinous loss, a trifling arithmetical error would have occasioned, and of the boundless confidence the parties must have had in their resources and in the correctness of their computations. Nevertheless, it was one great merit in Mr. Paxton's original details of measurement that they were contrived to facilitate calculation.
"There was little time for consideration, or for setting right a single mistake, were it ever so disastrous. On the prescribed day the tender was presented, with whatever imperfections it might have had, duly and irredeemably sealed. But after-checkings have divulged no material error."
The Royal Commission appear from the first to have been favourably impressed with Mr. Paxton's design, partly, no doubt, because its adoption would at once silence the great bricks-and-mortar objection to the occupation of the site in Hyde Park; and the result was that, on the 16th of July, Messrs. Fox and Henderson's tender of 79,800l.for Mr. Paxton's design was verbally accepted, and, as soon as the necessary arrangements could be made, the contract was formally concluded.
History of Mr. Paxton's Design.
AS Mr. Paxton himself has stated, the design for a building of such magnitude could not have been produced in so short a space of time without the aid of the experience he had gained in constructing other great buildings of a somewhat similar character; the progress of this experience Mr. Paxton has described in the lecture he delivered to the Society of Arts on the 13th of November, 1850, from which we have made the following extracts; and we hope to be excused by the reader for their copiousness, on the ground that no man can so well relate his own doings as the actor himself:—
"The Great Industrial Building now in the course of erection, and which forms the subject of the present paper, was not the production of a momentary consideration of the subject. Its peculiar construction, in cast-iron and glass, together with the manner of forming the vast roof, is the result of much experience in the erection of buildings of a similar kind, although on a smaller scale, which has gradually developed itself through a series of years. It may not, therefore, be uninteresting to give a brief account of the reasons which led me to investigate the subject of glass roofs and glass structures generally, and which have resulted in the Exhibition Building.
"In 1828, when I first turned my attention to the building and improvement of glass structures, the various forcing-houses at Chatsworth, as at other places, were formed of coarse thick glass and heavy woodwork, which rendered the roofs dark and gloomy, and, on this account, very ill suited for the purposes they were intended to answer. My first object was to remove this evil, and, in order to accomplish it, I lightened the rafters and sash-bars, by bevelling off their sides; and some houses which were afterwards built in this manner proved very satisfactory. I also at this time contrived a light sash-bar, having a groove for the reception of the glass; this groove completely obviated a disadvantage connected with the old mode of glazing, namely, the putty becoming continually displaced by sun, frost, and rain, after the sashes had been made for a short time, and the wet by this means finding its way betwixt the glass and the wood, and producing a continual drip in rainy weather.
"About this period the desire for metallic roofs began to extend in every direction; and as such structures had a light and graceful appearance, it became a question of importance as to the propriety of using metal sashes and rafters, instead of wooden ones, for horticultural purposes. After carefully observing the effects of those built by various persons, it became apparent to me that the expansion and contraction of metal would always militate against its general adoption, as at no season of the year could the sashes and rafters be made to fit.
"The extra expense, also, of erecting metallic-roofed houses was aconsideration. In 1833 I contemplated building a new range of hot-houses; and being desirous of knowing how much they would cost, if erected of metal, a plan of the range was prepared and sent to Birmingham, and another to Sheffield, with a desire to be furnished with estimates for that purpose. The estimate from Birmingham was 1,800l.; and the other, from Sheffield, was 1,850l.These appeared to me such enormous sums, that I at once set about calculating how much the range would cost if built of wood under my own inspection; and the result was, that I was able to complete the whole range, including masonry (which was omitted in the metal estimates), for less than 500l.
"Besides the extra cost of metallic roofs, we must add the extreme heat of such houses in hot weather, and their coldness in times of frost; the liability to breakage of glass from expansion and contraction of the metal; the very limited duration of the smaller portions, as sash-bars, from corrosion, by exposure to the alternations of heat, cold, and moisture, inseparable from gardening operations, and which could only be prevented by making use of the expensive material,COPPER; and the difficulty, when compared with wood, of repairing any damages, as a wooden roof could at any time be set to rights by a common carpenter. These different items formed in my mind so many objections to its use, and the same disadvantages soon became generally apparent.
"It was now thought advisable by some parties that, in order to obviate the many disadvantages in the use of metal, the rafters and frame-work of the sashes ought to be made of wood, and the sash-bars of metal. This plan certainly presented more advantages than the other, yet it was quite obvious that materials so incongruous could never give satisfaction; and accordingly, in a few years, as I had anticipated, the rage for these structures gradually subsided, and the use of wood again became resorted to by most persons, as the best material for horticultural purposes.
COMMON MODE OF GLAZING ROOFS.COMMON MODE OF GLAZING ROOFS.
COMMON MODE OF GLAZING ROOFS.
COMMON MODE OF GLAZING ROOFS.
"In the construction of glass-houses requiring much light, there always appeared to me one important objection, which no person seemed to have taken up or obviated; it was this. In plain lean-to or shed roofs, the morning and evening sun, which is on many accounts of the greatest importance in forcing fruits, presented its direct rays at a low angle, and, consequently, very obliquely to the glass. At those periods most ofthe rays of light and heat were obstructed by the position of the glass and heavy rafters, so that a considerable portion of time was lost both morning and evening; it consequently became evident that a system by which the glass would be more at right angles to the morning and evening rays of the sun would obviate the difficulty, and remove the obstruction to rays of light entering the house at an early and late hour of the day.
METHOD BY RIDGE-AND-FURROW.METHOD BY RIDGE-AND-FURROW.
METHOD BY RIDGE-AND-FURROW.
METHOD BY RIDGE-AND-FURROW.
"This led me to the adoption of the ridge-and-furrow principle for glass roofs, which places the glass in such a position that the rays of light in the mornings and evenings enter the house without obstruction, and present themselves more perpendicularly to the glass at those times when they are the least powerful; whereas at mid-day, when they are most powerful, they present themselves more obliquely to the glass. Having had this principle fixed in my mind, and being convinced of its importance, I constructed a pine-house in 1833 as an experiment, which still exists unimpaired, and has been found fully to answer the purpose.
"In 1834 I resolved to try a further experiment on a larger scale, on the ridge-and-furrow principle, in the construction of a green-house of considerable dimensions, which also remains and answers admirably. For this building I made a still lighter sash-bar than any I had previously used; on which account the house, when completed (although possessing all the advantages of wood), was as light as if constructed of metal. The whole length of this structure is 97½ feet, and its breadth 26 feet; the height at the back is 16 feet 9 inches, and in the front 12 feet 3 inches. A span so large as 26 feet could not be safely covered with a roof constructed in the ordinary way, unless the sash-bars were stronger, and the assistance of heavy rafters and numerous supports was afforded. The house presents a neat and light appearance, and consists of 15 bays, and pediments in front, supported by 16 slender reeded cast-iron columns. Whilst it makes an admirable green-house, it is also an economical building; for, at the period of its construction, notwithstanding the heavy tax on glass (since removed), it only cost at the rate of twopence and a fraction per cubic foot. At the present time, considering the change in the price of material, and the removal of the glass-tax, it could be constructed at a considerably smaller amount.
"Having in contemplation the erection of the Great Conservatory in its present form, it was determined, in 1836, to erect a new curvilinearhot-house 60 feet in length and 26 feet in width, with the elliptical roof on the ridge-and-furrow principle, to be constructed entirely of wood, for the purpose of exhibiting how roofs of this kind could be supported. The plan adopted was this: the curved rafters were composed of several boards securely nailed together on templets of wood cut to the exact curve; by this means a strength and firmness were obtained sufficient to support an enormous weight.
"In 1837 the foundations of the Great Conservatory were commenced; and in constructing so great a building it was found desirable to contrive some means for abridging the great amount of manual labour that would be required in making the immense number of sash-bars requisite for the purpose. Accordingly, I visited all the great workshops in London, Manchester, and Birmingham, to see if anything had been invented that would afford the facilities I required. The only apparatus met with was a grooving-machine, which I had at once connected with a steam-engine at Chatsworth, and which was subsequently so improved as to make the sash-bar complete.
CUTTERS OF MR. PAXTON'S SASH-BAR MACHINE.CUTTERS OF MR. PAXTON'S SASH-BAR MACHINE.
CUTTERS OF MR. PAXTON'S SASH-BAR MACHINE.
CUTTERS OF MR. PAXTON'S SASH-BAR MACHINE.
"For this apparatus the Society of Arts, in April, 1841, awarded me a medal; and this machine is the type from which all the sash-bar machines found in use throughout the country at the present time are taken. As the Conservatory was erected under my own immediate superintendence, I am able to speak accurately as to the advantages of the machine: it has, in regard to that building alone, saved in expenses 1,400l.The length of each of the bars of the Conservatory is 48 inches; only one inch shorter than those of the Exhibition Building. The machine was first used in its present form in August, 1838; and its original cost, including table, wheels, and everything complete, was 20l.The motive power is from a steam-engine employed on the premises for other purposes; and any well-seasoned timber may be used. The attendants required are only a man and a boy, and the expense of the power required for it when in use is comparatively trifling. The sash-bars may be made of any form, by changing the character of the saws.
"There is one particular feature in working the machine, namely, the bar is presented to the saws below the centre of motion, instead of above it (as is usual); and to the sides of the saw which are ascending from the table, instead of those which are descending. These arrangements were necessary to suit the direction of the teeth to the grain of the wood; for when the bars were presented to the saws in the usual way, the wood wascrushed instead of being cut and cleaned. It is essential that the machine should revolve 1,200 times in a minute to finish the work in a proper manner.
"The glass and glazing of the Chatsworth Conservatory caused me considerable thought and anxiety, as I was very desirous to do away altogether with the numerous overlaps connected with the old system of glazing with short lengths. This old method, even under the best of management, is certain, in the course of a few years, to render unsightly any structure, however well built.
"In the course of my inquiries, I heard that Messrs. Chance and Co., of Birmingham, had just introduced from the Continent the manufacture of sheet glass. Accordingly, I went to see them make this new article, and found they were able to manufacture it three feet in length. I was advised to use this glass in two lengths, with one overlap; but to this I could not assent, as I observed, that since they had so far advanced as to be able to produce sheets three feet in length, I saw no reason why they could not accomplish another foot; and, if this could not be done, I would decline giving the order, as, at that time, sheet glass was altogether an experiment for horticultural purposes. These gentlemen, however, shortly afterwards informed me that they had one person who could make it the desired length, and, if I would give the order, they would furnish me with all I required.
"It may just be remarked here that the glass for the Exhibition Building is forty-nine inches long—a size which no country except England is able to furnish in any large quantity, even at the present day.
"In 1840 the Chatsworth Conservatory was completed and planted. The whole length of this building is 277 feet; its breadth, 123 feet over the walls; and the height, from the floor to the highest part, 67 feet.
"Notwithstanding the success which attended the erection of these buildings, it became to me a question of importance how far an extensive structure might be covered in withflatridge-and-furrow roofs; that is, the ridge-and-valley rafters placed on a level, instead of at an inclination, as in the green-house, or curvilinear, as in the Great Conservatory. I therefore prepared some plans for an erection of the kind for the Earl of Burlington, somewhere about ten years ago; but, on account of the lamented death of the Countess, the design of erection was abandoned. However, from that time I felt assured, not only that it could be done satisfactorily, but that the most appropriate manner to form and support level glass roofs, to a great extent, was that adopted this year for the New Victoria House at Chatsworth, which may be considered a miniature type of the Great Industrial Building.
"Before describing this house, however, it may be well to notice twoinstances in which the flat roofs had been previously tried, and in both cases with the most perfect success.
"The first of these was a conservatory attached to a villa in Darley Dale, only a short distance from Chatsworth. This building is divided into five bays, with a glass door in the centre, and glass pilasters separating the bays; the ridge-and-furrow roof covers an opening of seventeen feet in the clear. The ventilation is simultaneously effected by a lever connected with a rod, which is attached to all the ventilators....
THE VICTORIA REGIA HOUSE, CHATSWORTH.THE VICTORIA REGIA HOUSE, CHATSWORTH.
THE VICTORIA REGIA HOUSE, CHATSWORTH.
THE VICTORIA REGIA HOUSE, CHATSWORTH.
"The second instance is this. In the spring of 1848, plans were prepared for the erection of an ornamental glass structure, to cover the conservatory wall at Chatsworth. This wall was previously a plain flued structure, devoted to the growth of rare and choice plants. The new erection is 331 feet in length, and 7 feet in width. It is divided into ten bays, with an ornamental centre projecting beyond the general line of the building. Each bay is subdivided by smaller bays, which are separated by glass pilasters; the glass sashes are so arranged that they can be removed in summer, and the whole thrown open to the gardens, whilst in winter the building affords an extensive promenade under cover. The ground on which this structure is built has a fall of 25 feet 6 inches in its whole length; consequently, there is a proportionate fall at each bay, which gives great variety, and obviates the monotony that would be exhibited in a building of such length and dimensions placed on a uniform level. The lower side of each bay is finished by a glass pilaster, three feet in width, and surmounted by a vase on the wall behind. The roof is on the ridge-and-furrow principle, with the rafters on a very slight inclination; and the ventilation is effected in a similar but more perfect manner than that already described as in use at the conservatory at Darley Dale.
"The new Victoria Regia House, which presents a light and novel appearance, is 60 feet 6 inches in length, and 46 feet 9 inches in breadth. Although, when compared with the Great Industrial Building, the Victoria House is a very diminutive structure, yet the principles on which it is constructed are the same, and may be carried out to an almost unlimited extent. The form of the roof, the general elevation, the supports, and the mode of construction, are all quite simple, and yet fully answer the purposes for which they were intended.
INTERIOR OF VICTORIA REGIA HOUSE.INTERIOR OF VICTORIA REGIA HOUSE.
INTERIOR OF VICTORIA REGIA HOUSE.
INTERIOR OF VICTORIA REGIA HOUSE.
"The Victoria House, however, was so built as to retain as much moisture and heat as possible, and yet to afford a strong and bright light at all seasons; whilst, on the contrary, the Industrial Building, being intended to accommodate a daily assemblage of many thousands of individuals, and a vast number of natural and mechanical productions, many of which would be destroyed by moisture and heat, is constructed so as fully to answer that end."
This, then, was the experience which enabled Mr. Paxton to conceive his design for the "Crystal Palace," a description of which as it has subsequently been carried out we must now proceed with.
General Description of the Building.
THE plan forms a parallelogram, 1,848 feet long and 408 feet wide, besides a projection on the north side, 48 feet wide and 936 feet long. A main avenue, 72 feet wide and 66 feet high, occupies the centre through the whole length of the building. Flanking this on either side are smaller avenues alternately 24 feet and 48 feet wide; the two first on either side of the centre are 43 feet, and the remainder 23 feet high. About the centre of the entire length, at a point determined by the position of a row of large trees, which it was resolved to inclose, these avenues are crossed by a transept of the same width as the main avenue, or 72 feet, and 108 feet high; two other groups of trees on the ground give occasion for open courts, which are inclosed within the building. The area thus inclosed and roofed over amounts to no less than 772,784 square feet, or about 19 acres;[4]the building is, therefore, about four times the size of St. Peter's at Rome, and more than six times that of St. Paul's, London. Three entrances lead to this vast interior, one in the centre of the principal or south front, and one at either end of the building. The number of these is necessarily small, in order to facilitate the arrangements for the money-taking, and to avoid having too large a staff of officers; on the other hand, it was equally desirable to afford the most ample opportunities of egress for visitors, and accordingly fifteen exit doors are placed at frequent intervals.
GROUND-PLAN OF THE BUILDING.
?01126A. Principal Entrance.B. West Entrance.C. East Entrance.D. Refreshment Courts.E. Entrance.F. Gentlemens' Ante-rooms.G. Ladies' Ante-rooms.H. Pay Place.I. Accountant.K. Exits.L. Ante-rooms.M. Committee Waiting-room.N. Royal Commission.O. Clerks.P. Stairs.Q. Engine House.
A. Principal Entrance.B. West Entrance.C. East Entrance.D. Refreshment Courts.E. Entrance.F. Gentlemens' Ante-rooms.G. Ladies' Ante-rooms.H. Pay Place.I. Accountant.K. Exits.L. Ante-rooms.M. Committee Waiting-room.N. Royal Commission.O. Clerks.P. Stairs.Q. Engine House.
It will be well to mention here that the horizontal measure of 24 feet, which we have seen as the unit in the plan of the Building Committee, is also preserved in the present plan; every horizontal dimension of which is either a certain number of times or divisions of twenty-four feet.
The avenues into which the plan is divided are formed by hollow cast-iron columns twenty-four feet apart, which rise in one, two, and three storeys respectively, to support the roof at the different heights given above; in the lower storey these columns are nineteen feet high, and in the two upper ones seventeen feet. Between the different lengths of the columns short pieces are introduced, called "connecting-pieces," from the office they perform; these are three feet long, and are so contrived that they serve to support girders in horizontal tiers, dividing the greatest height into three storeys as already mentioned. The girders, of which some are of cast and some of wrought iron, are all of the same depth, namely, three feet, with the exception of four, to be specially named hereafter, and by this arrangement the same horizontal lines are preserved throughout the whole of the building. They are also all similar in appearance, forming a kind of lattice-work, by which construction they do not look too heavy for the slight supports; and large solid masses are avoided, practically showing how great strength may be combined with elegance and lightness. The first or lower tier of these girders, in parts of the building more than one storey in height, forms the support for the floor of the galleries, which are twenty-four feet wide, and extend the whole length of the building in four parallel lines, intercepted only by the transept, round the ends of which they are continued. Numerous cross galleries connect each pair of longitudinal lines on either side of the centre avenue, which remains uninterrupted from end to end, and can only be crossed on the gallery-floor at the extremities.
These galleries are reached by eight double staircases, of easy ascent and ample width, which are placed between the lines of gallery so as to communicate equally readily with either, and are so distributed as to give two to each quarter of the building; in the eastern or foreign half two supplementary staircases of smaller dimensions have been added.
In those parts of the building more than two storeys in height, the second horizontal tier of girders does not support a gallery, but serves only to give stiffness to the columns. The upper tier of girders, in all cases, supports the roof, which is one of the most peculiar features in the structure. In its general form the roof is flat; but it is made up of a series of ridges and furrows, the rise and fall of which is but small, and is thus arranged: the roof-girders or trusses being twenty-four feet apart, and lying in the transverse direction of the building, the space between them is spanned by light beams or rafters, which are cambered or bent upwards, and are hollowed out in a groove on the top to form a gutter. The rafters are placed eight feet apart, their ends resting on the roof-girders, and lying, therefore, in the opposite direction to them, that is, in the directionof the length of the building; these rafters are commonly called the Paxton's Gutters. Between the rafters so described,ridgesare supported by light sash-bars sloping up to them, at an inclination of two-and-a-half to one, and the rafter itself forms the bottom of thefurrow. The advantage of this form of roofing is the facility it affords for the escape of the water, which runs from the surface of the roof into the Paxton's gutters; from them it is discharged into the main gutters resting on the roof-girders, by which it is conducted to the hollow columns, and passes down through them into the drains. A drop of water falling on the most distant point from the discharge would only have to traverse a distance of forty-eight feet; but in most cases the length to be passed over before reaching the down pipe would be considerably less.[5]The covering of the roof is glass, fixed between the sash-bars, which are grooved to receive it; and in order to carry off the moisture arising from condensation on the inner surface of the glass, the rafters have a small groove on each side, which makes the Paxton's gutter complete, and from which the moisture is also discharged into the main gutters. The essential portions of the roof may therefore be considered as a network of gutters; one set, the main gutters, lying in a transverse direction, and the others resting on them, and lying in the direction of the length of the building; by which arrangement any amount of surface can always be covered by roofing of a small span. The principle is precisely the same as that of subdividing large fields of arable land into strips or "lands" with furrows between them, in order to facilitate the surface-drainage.
VIEW OF ONE 24-FEET SQUARE BAY OF ROOF PARTLY COMPLETED.VIEW OF ONE 24-FEET SQUARE BAY OF ROOF PARTLY COMPLETED.
VIEW OF ONE 24-FEET SQUARE BAY OF ROOF PARTLY COMPLETED.
VIEW OF ONE 24-FEET SQUARE BAY OF ROOF PARTLY COMPLETED.
The outer inclosure, on the ground-floor, is formed by dividing each 24-feet bay between the columns into three 8-feet bays by half columns of wood, between which is placed boarding, held in its place by iron clips and bolts; a plinth, four feet high, is formed immediately above the floor by frames, filled with what are commonly called louvre-blades, which are hung on pivots, and of which a large number can be moved simultaneously for the admission of air; similar ventilating-frames, three feet deep, are introduced at the top of each storey round the entire circuit of the building, and by this means a ventilating-surface of no less than 40,800 square feet is obtained, or rather more than one acre.
PORTION OF THE LOWER STOREY OF THE PRINCIPAL ELEVATIONS.PORTION OF THE LOWER STOREY OF THE PRINCIPAL ELEVATIONS.
PORTION OF THE LOWER STOREY OF THE PRINCIPAL ELEVATIONS.
PORTION OF THE LOWER STOREY OF THE PRINCIPAL ELEVATIONS.
Externally some light arches are inserted, and open panels form the inclosure for the upper louvre-frames. The details we have been describing may be readily traced in the engraving of a portion of the lower storey as seen from the outside. The exit doors occupy one of the 8-feet bays opening about six feet wide. The inclosure to the upper storeys closely resembles those of the ground-floor, but glazed sashes are substituted for the close boarding, and the plinth is omitted. Each storey is crowned externally with a cornice and cresting ornament, and over the columns posts are carried up, to which flagstaffs will be fixed.
To return to the interior. The whole of the floor is boarded; that below is laid with an interval of half an inch between the boards, to allow the passage of dust from the millions of feet by which it will be trod; the gallery floor, on the contrary, has iron tongues between the boards to prevent the dust from coming through on the heads of the visitors below.
The roof of the transept, which we have described as crossing the building about the centre of its length, differs from that of the other parts, its general form being semicircular instead of flat, and rising above the restof the building so as to show the whole of the semicircle externally. This roof is supported by arched timber ribs placed twenty-four feet apart, or one over every column, which forms a socket, into which the foot of the rib is fitted and secured by iron straps. Between the ribs, timbers are fixed which carry minor ribs at a distance of eight feet apart, and upon these the ridge-and-furrow roofing is constructed in the manner that has been described for the flat roofing, but following the curve of the arched ribs. At the springing or foot of the arch on either side of the transept there is a range of louvre-frames to assist in the ventilation of the building, and on the top of the arch externally a narrow passage is formed to give access to the different parts of this roof. On the inner side of the arch diagonal tie-rods are introduced between the main ribs, which, while they serve to increase the strength of the construction by tying together all the parts from end to end, produce an agreeable play of lines forming a kind of network over the whole of the surface.
The ends of the transept are closed in with fan-like tracery, reminding the spectator of the magnificent wheel windows of our Gothic cathedrals; this elegant feature is not visible in our interior view, but will be seen in some of the exteriors.
There is, perhaps, no part of this interesting building in which the great size and singular lightness, almost airiness, of the construction are so strikingly displayed as in theTRANSEPT, inclosing as it does a row of fine old elm-trees, as if to protect them in their venerable age from the smoke of the thousands of chimneys that have been gradually forming a destructive circle around them.
The only portion of solid untransparent roofing in the whole of this building is formed on either side of the arched roof just described, where there is a lead flat twenty-four feet wide. This was partly required for a platform to serve for carrying on the works for the arched roof, and was also exceedingly useful in giving access to the other roofs on either side; it likewise afforded the opportunity of giving some additional strength at the springing of the arched ribs to resist any possible tendency they might have to spread outwards.
View of the Interior of the Transept.View of the Interior of the Transept.
View of the Interior of the Transept.
View of the Interior of the Transept.
View of Glass Roof from the Lead Flat.View of Glass Roof from the Lead Flat.
View of Glass Roof from the Lead Flat.
View of Glass Roof from the Lead Flat.
As the weight of such lead roofing considerably exceeds that of the glass ridge-and-furrow covering, it was necessary at the point where it crosses the wide span of the main avenue to introduce some stronger roof-girders than those used elsewhere; of these there are two on either side of the transept, the inner one of which has also to sustain two of the large arched ribs with their superincumbent roofing, and its strength is therefore increased in proportion to the additional load placed upon it. The extra-strong roof-girders are six feet deep, or twice that of the others; but their general construction is similar, the diagonal ties forming a kind of latticework, and thus keeping up the same character. These, like all the roof-girders of large span, are constructed principally of wrought-iron. Those who visited the building during its erection, and were among the fortunate few who were enabled to ascend to the "lead-flat," must have been very much struck with the singular appearance presented by the great expanse of acres of glass stretching in long lines of "ridge-and-furrow" roofing on each side of the centre, while the eye, penetrating the transparent covering, became lost in endeavouring to follow the apparently intricate lines of the interior. Such a view might fairly be said to justify the title of "Crystal Palace," by which this building is so commonly known; and it would require no great stretch of imagination to believe that it had been reared by fairy hands, as a votive offering at the world's jubilee of labour.
But we must descend again to the interior, to point out the arrangement of the offices for the staff of the Executive. The principal of these are naturally placed in the centre, on either side of the principal entrance, where they occupy in two storeys the space underneath the gallery, which is continued uninterrupted over them. The entrances at the end are also flanked by offices of less extent. The outer inclosure of these spaces is formed with glazed sashes, similar to those which are placed on the exterior of the building, and boarded partitions divide the interior. The rooms are arranged to be heated and lighted by gas when required, and ample means of ventilation are provided.
The simplicity of the construction renders it very easy to extend or contract the accommodation much more readily than would be possible under ordinary circumstances.
It now remains to notice the arrangements provided for refreshments, which are introduced in connexion with the open courts left on account of the groups of trees. These happen to occur towards the ends of the building, and on the north side of the main avenue; the space at the north end of the transept, next to the inclosed trees, is also appropriated for this purpose. The roofing over these parts is a continuation of that over the rest of the building; and the partitions necessary for inclosing the different spaces are formed chiefly with glazed sashes, avoiding as much as possible any solid construction, which would appear out of character. The open courts are inclosed with sashes and doors, rendered necessary by the uncertain nature of our climate.
A small detached building which has not been mentioned serves for the boiler-house, and is placed near the west end of the building. As it had been determined to afford the means of exhibiting some of the machinery in actual motion, it was necessary to erect boilers to supply the steam to the different machines, as it would clearly be inadmissible for each to generate steam for its own use in the building. The house to contain the boilers is ninety-six feet long and twenty-four feet wide, and is placed as near as practicable to the machinery-department; but at the same time it is quite detached from the main building to avoid risk from the fires. In appearance it resembles the one-storey portion of the main building, but it is constructed entirely of fire-proof materials. It contains five boilers, each to supply steam for twenty-horse power, which is distributed by a pipe to the different machinery.