From the point of view of library equipment and management, however,
the three great book-stacks radiating from the Rotunda are the
most interesting and remarkable feature of the building. They were
entirely planned by Mr. Bernard R. Green, the engineer in charge
of the construction of the Library. The word “planned,” indeed, is
hardly adequate; “invented” would be nearer the exact fact. The
idea of a book-stack, as distinguished from a mere arrangement of
bookcases, is so new that such examples as were in existence when Mr.
Green entered upon the work were imperfect in many very important
points.
[Illustration: PLATO. BY JOHN J. BOYLE.]
The root purpose of a book-stack, of course, is to make it capable
of holding the greatest number of volumes in the smallest possible
space--always, however, bearing in mind that every book must be
perfectly accessible and so placed that it can be easily and quickly
handled. The space being limited and the number of volumes large, the
old way of arranging cases along the walls, even when the wall space
is materially increased by dividing a room into alcoves, has to be
abandoned in favor of a more compact system. The modern substitute is
to erect the cases in stories, or tiers, with corridors and passages
only large enough to give convenient access to the books. Throughout,
the aim of the builder is to dispose of every inch of space as
economically as possible. Of the three stacks in the Library of
Congress, those to the north and south are, as the visitor has seen,
the largest, each having a length of one hundred and twelve feet
against thirty for the East Stack. All three are of the same width,
however--forty-five feet--and the same height--sixty-three feet. The
method of construction is the same throughout, and each is absolutely
fireproof, the only materials used being steel, iron, brick, glass,
and marble. Few things which can be destroyed by fire at all are
more difficult to burn than books, and a fire in the stacks, even
if carefully nursed by an incendiary, could hardly do more than a
trifling injury.
=Arrangement and Construction.=--The stacks are divided into nine
tiers, each tier being seven feet high, and into an equal number of
stories the same distance apart. This distance was adopted in order
that the books on the highest shelf of a tier might not be beyond the
convenient reach of a man of average height, or so far away that he
could not easily read their titles. By the present arrangement every
book can be handled or its title read without effort.
The stacks begin at the basement story, which is fourteen feet below
the level of the floor of the Rotunda. They are sixty-three feet in
height--the sum, that is, of the nine seven-foot stories--and are
topped by an iron covering, so that any water which might by accident
come through the roof would be shed without harming the books. The
construction of the shelving is entirely of steel and iron. The unit
of construction, as it may be technically called, is a steel column
erected on a firm foundation and extending the height of the stack.
There are over three hundred of them in each of the two large stacks.
At the bottom of every tier above the basement is a horizontal
framework of steel bars, running between the columns, the length
and width of the stack, and securely anchored to the walls. These
cross-pieces perform a double service: they brace the upright columns
and prevent them from bending under the weight they bear, and they
are supports on which to lay the decks. The cases, that is, do not
rest on the flooring, but the flooring on the general system of the
cases. It may be added that with the strong and simple framing that
is used the stacks might very well have been carried a dozen stories
higher without materially increasing the size of the columns.
The ranges--by which is meant the cases for books--are of iron,
divided into six compartments by partitions bolted to the columns.
They are double-faced, each side being a foot deep, and have no
backs. On the front edge of each partition are blunt teeth, and near
the back edge is a vertical row of horns, both serving to hold the
shelves in place. The ranges are at right angles with the wall, so
that there is no opportunity for the occurrence of what are called
“dead angles”--waste spaces in which it is impossible to put books.
[Illustration: GIBBON. BY CHARLES H. NIEHAUS.]
The ranges are nineteen and a quarter feet long, and in both of the
larger stacks are forty-two in number, twenty-one on each side of
the stack, leaving a corridor between every story the length of the
gallery. Between them are aisles three feet four inches wide. Near
the middle of the stack a couple of ranges are omitted to give room
for staircases up and down, an elevator well, large enough to carry
an attendant and a truck-load of books; and the shaft or well for the
book-carriage service.
The decks themselves are of white marble, two and a half feet wide
in the aisles and five and a half in the corridors, set in an iron
frame. This leaves a five-inch slit on either side, between it and
the range. The space is too narrow and too close to the range for
anyone to step through, and in order that any small article may
not roll off, the deck is protected by a raised edge. It would, of
course, be possible, though difficult, to drop a book down the slit,
in which case, however, it would be very sure to lodge long before
it struck the basement floor. If found necessary, any such accident
could be prevented by protecting the opening with a wire netting. The
advantages of an open space are many, however: attendants may speak
to one another from deck to deck without the trouble of going to the
stairways; light is diffused through it; and it keeps the books on
the lower shelves from damage, either by being carelessly struck by
the foot or one of the wheeled trucks used to carry books from the
shelves to the elevator well.
=Ventilation and Heating.=--Especially, by allowing a free
circulation of air, these desk-slits help to heat and ventilate the
stacks. Ventilation is especially important. Books require pure
air almost as much as human beings do; if they do not get it they
grow “musty,” and gradually decay. As will have been seen, the
whole structure of the stack is open; nothing is closed, even the
partitions in the ranges being made in the form of gratings. The
system of ventilation and heating is one and the same, and both
require the freest circulation of air. Air is taken into the cellar
through the windows looking out into the court-yards, first, however,
passing through filters of cotton cloth to exclude all dust; after
being warmed it ascends through gratings to the roof, where it
passes out through ventilating flues. In this way the temperature is
everywhere kept very nearly even. Electric fans are ready for use in
case of any sluggishness in the circulation, and in summer are also
used for sending cooled air into the stack.
=The Shelving.=--The shelves themselves are open, being composed
of parallel strips of steel with a narrow space between. The total
number of shelves in the three stacks is sixty-nine thousand two
hundred. Each is one foot wide and thirty-eight inches long,
with a total length of forty and a half miles. They are capable
of sustaining a weight of forty pounds a square foot--more than
will ever be required of them--with practically no deflection.
Nevertheless, though so much stiffer, they are as light as the
ordinary board shelf of the same size. They can be easily and quickly
adjusted at any height, without the need of pegs or loose screws.
Once in place they cannot slip or tip, and being made in a uniform
size (with some small exceptions for certain irregular spaces around
stairways, etc.), every shelf is available for use anywhere. There
are no rough edges or projections on which a book can wear, and the
parallel strips of steel are rounded and highly polished by means
of the Bower-Barff process of coating with magnetic oxide of iron,
so that the surface is as smooth as glass--which not only helps to
preserve the books, but can offer no lodgement for dust or insects.
The open spaces, also, afford an opportunity for using a workable
book-brace, specially devised by Mr. Green.
Furthermore, the shelves can be removed from any compartment as
desired, and space thus made for a table, a cabinet, or a desk, as
needed; or an extra corridor can be at once opened for any distance.
Then again, in case of the extra large books, sufficient space may be
made by placing the shelves of both sides of the range on a level.
[Illustration: THE ROTUNDA, LOOKING EAST.]
=Lighting.=--No point was more carefully studied in the construction
of the stacks than the lighting. Preliminary plans requiring an
immense amount of labor were made, showing the amount of direct
sunlight which any portion of the three arms would receive at any
hour of the day, any month in the year. Skylights along the line of
the corridors help light the upper tiers. The walls are honeycombed
with windows from top to bottom. In the north and south stacks there
are no less than three hundred and sixty. They occur at the ends of
the passageways between the ranges, being placed at the intersections
of the decks, so that each may diffuse direct light into two tiers
at once. In this way there can be no perceptible difference in the
amount of light cast into the upper and lower portions of the tiers.
At the end of each passageway the window is fitted with a seat for
the use of the readers admitted to the stacks, or attendants. Ground
glass is employed for the windows on the east side of the south
stack, where the sunlight is so abundant and continuous that it
would be inconvenient if admitted, besides being likely to cause the
bindings of the books to fade; everywhere else the clear open plates
invite the entrance of all the illumination which can be obtained.
Each window consists of a single piece of polished plate glass three
feet wide, and permanently sealed, so that no dust or moisture can
ever penetrate it. In order to wash the glass from the outside the
wall is fitted at convenient intervals with skeleton galleries.
The courts themselves give an abundance of full, bright light; and
that none of it may be wasted, and in order that it may be evenly
distributed through the tiers, both at the bottom and top of the
stacks, the walls of the courts are constructed of yellow enamelled
brick, which makes an admirable reflector, on rainy as well as on
sunny days. Inside, the marble decks are highly polished, so that
they, too, serve as efficient reflectors, casting the light which
they receive into every nook and cranny of the stack. Evenings, the
light is furnished by incandescent lamps, with which the passages and
corridors are abundantly equipped, and here again the polished decks
serve a most useful purpose in diffusing the brilliant illumination
throughout the whole system of shelving. Altogether, it may be very
confidently stated that no great collection of books was ever before
so thoroughly and conveniently lighted, whether in the day or at
night.