light and heat adjusters, rain conductors
outside, and condensed moisture ducts within.
They are interminable rows of roofing,
so placed as to form in the aggregate a
plane; in other words, they are parallel rows
of the letter V done in glass, in endless
ridges "long drawn out," thus: {image:text:[VVV]}
The apex of each "ridge" is a wooden sash
bar, with notches on either side for holding
the sloping laths in which are fitted the edges of
the glass. The bottom, or "furrow" bar—
otherwise a rafter—is hollowed in the middle,
to form a gutter, into which every drop of
rain glides down from the glass, and passes
through the transverse gutters into the hollow
columns. These longitudinal gutters are
formed at the tops of the girders; for the
roof is self-supporting. This is not all: in
converting a conservatory for plants into
a resort for breathing beings, and a depôt
for articles emphatically "to be kept dry;"
internal as well as external moisture must
be drawn off: the breath of myriads of
visitors, condensed against the glass, would
otherwise return in continual Scotch mists.
That difficulty partly dictated the ?-like form
of the ceiling. Mr. Paxton ascertained that
vapours ascending to glass inclined to a slope
of one foot in two feet and a-half, do not
condense in separate drops and descend
again, but slide down over the smooth
surface. To receive them, therefore, he grooves
each rafter under the inside of the glazing.
Into these grooves the condensed breath of
"all nations" will fall and be conveyed into
the transverse gutters; thence through the
columns into the jurisdiction of their honours
the Commissioners of Sewers. {image:ducts and gutters diagram}
We subjoin a section of the
rafter, to show the "Paxton
gutter," and to clench our
explanation: A is the external
gutter, B B the frames of the
glass, C C the internal ducts.
These ingenious rafters are cut out of solid
wood, in a machine (invented by the inventor
of all the rest), with incredible rapidity. In
order that there may be a fall for the water to
run off, each rafter is slightly curved; and, to
correct warping, a rod of iron, with nuts and
screws at each end, forms the string of the
bow, so as to regulate its deflexion. For this
ingenious expedient Mr. Paxton has taken out
a patent.

We must now give proof that the floor is
a ventilator, and a dust-trap. It is laid four
feet above the sward of the park. A series
of subterraneous lungs are thus provided,
and air is admitted to them, by means of
louvres, fixed in the outer walling of the
building. These being made to open and shut
like Venetian blinds, will admit much or little
air, which gently passes through the seams of
the open flooring, and circulates over the
building. Finally, through the openings of
the floor, the daily accumulations of dust will
be swept into the space below by a machine,
which Mr. Paxton has invented for that
purpose.

Enough has now been said to indicate
rather than to describe how each part of the
building "plays many parts," and how,
consequently, incalculable saving has been effected
in time and money. It is hardly necessary to
repeat, that the interior of the edifice is
the most expansive covered space in the
world. That some idea may be formed or
the excess of its capacity, we may mention,
that the largest covered area in England is
believed to be that of the Ravenhead Glass
Works, at St. Helen's, in Lancashire, where
the space roofed-in is three hundred and
thirty-nine feet, by one hundred and five feet,
or not one quarter so large as that section of
Hyde Park which Mr. Paxton has glazed over.

That a Palatial Exhibition building,
providing a total exhibiting surface of twenty-two
acres, and affording space for nine miles of
tables, shall have been put up in four months, for
less than a penny farthing a cubic foot, would
in itself make 1851 famous in the history of
enterprise, if nothing else were to happen to
stamp it as pre-eminently "The Industrial
Year." From it will at least be dated a new
era in building. In a communication from
Mr. Paxton himself, which we are permitted
to quote, he says:—

"When I consider the cheapness of glass
and cast-iron, and the great facility with
which they can be used, I have no doubt but
many structures, similar to that at Darley,*
will be attached to dwelling-houses, where
they may serve as sitting-rooms, conservatories,
waiting-rooms, or omnibus-rooms, if I
may be allowed the expression. I am now,
in fact, engaged in making the design for a
gentleman's house to be covered wholly with
glass; and when we consider that wherever
lead is now used, glass may with equal
propriety be substituted, I have every hope that
it will be used for buildings of various conditions
and character. Structures of this kind
are also susceptible of the highest kind of
ornamentation in stained glass and general
painting. I am not without hope, however,
that glass will become almost universal in its
use, and that the system will be extended for
manufacturing purposes, as well as general
cemeteries, and also for horticultural buildings,
so that even market-gardeners will
advantageously apply it, in the growing, of
foreign fruit for the London markets. I even
go so far as to indulge in the sanguine hope that
agriculture will be ultimately benefited by the
application of cast-iron and glass. In short,
there is no limit to the uses to which they may
be applied; and we may congratulate
ourselves, that in the nineteenth century the
progress of science, and the spirit of manufacturers,
have placed at our disposal the application
of materials which were unknown to the
ancients, and thereby enabled us to erect
*A conservatory on the new plan, attached to a house
of Mr. Paxton's, in Derbyshire.