e known to have been added in the 17th century by Thomas
Thornton, D.D., Canon Residentiary.

[Illustration: Fig. 72. Bookcase in the Chapter Library, Hereford
Cathedral.

[Illustration: Fig. 74. Part of a single volume, shewing the clasp, the
ring for the chain, and the mode of attaching it: Hereford.]

From a sketch taken in 1876.]

[Illustration: Fig. 75. A single volume, standing on the shelf, with the
chain attached to the iron bar: Hereford.]

[Illustration: Fig. 76. Iron bar and socket, closed to prevent removal of
the bar: Hereford.]

As the books were to stand upright on a shelf, not to lie on their sides
on a desk, it was necessary to attach the chain in a different manner. A
narrow strip of flat brass was passed round the left-hand board (fig. 74)
and riveted to it, in such a manner as to leave a loop in front of the
edge of the board, wide enough to admit an iron ring, an inch and a
quarter in diameter, to which one end of the chain was fastened. The book
is placed on the shelf with the fore-edge turned outwards, and the other
end of the chain is fastened to a second ring, rather larger than the
former, which plays along an iron bar (fig. 75). For the two upper shelves
these bars, which are 1/2 in. in diameter, are supported in front of the
shelf, at such a distance from it as to allow of easy play for the rings
(fig. 73). Each bar extends only from partition to partition, so that
three bars are needed for each shelf. For the lowest shelf there are also
three bars, set two inches behind the edge of the shelf, so as to keep the
rings and chains out of the way of the desk. The bars for the upper
shelves rest in iron sockets screwed to the woodwork at the juncture of
the horizontal shelves with the vertical divisions and ends respectively.
The socket fixed to the end of the bookcase which was intended to stand
against the wall is closed by an iron plate (fig. 76), so that the bar
cannot pass beyond it. At the opposite end, that which would usually face
the alley between the two rows of bookcases, the bars are secured by lock
and key in the following manner. A piece of flat iron is nailed to the end
of the bookcase, just above the level of the uppermost shelf (fig. 77).
Attached to this by a hinge is a hasp, or band of iron, two inches wide,
and rather longer than the interval between the two shelves. Opposite to
each shelf this iron band expands into a semicircular plate, to which a
cap is riveted for the