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 79,800_l._ 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 a
consideration. 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 1,800_l._; and the other, from
Sheffield, was 1,850_l._ 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 500_l._
"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.
[Illustration: 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 of
the 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.
[Illustration: 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 curvilinear
hot-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.
[Illustration: 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 1,400_l._ 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 20_l._ 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 was crushed 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 with _flat_ ridge-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 two
instances 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....
[Illustration: 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.
[Illustration: 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.
[Illustration]
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 direction of the length of the building; these rafters are
commonly called the Paxton's Gutters. Between the rafters so described,
_ridges_ are 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 the _furrow_. 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.
[Illustration: VIEW OF ONE 24-FEET SQUARE BAY OF ROOF PARTLY COMPLETED.]