ections are sewn continuously in a long
line, and are afterwards cut apart. The threads catch into hooked
needles and are drawn through holes made by piercers set to a certain
distance; a shuttle like that used in an ordinary sewing-machine sews
the inner thread backwards and forwards. Each section is placed upon a
sort of metal saddle by the hand of the operator, one after the other,
the machine working continuously unless the action is cut off or
controlled by a foot-lever or pedal. This machine is much quieter to
work, and although the inner threads are too bulky to be quite
satisfactory, this is not a serious matter like the cutting of the
upper and lower edges of the back already described, and, moreover, is
probably capable of being either improved away or so minimized that it
will become of small importance.

The Martini book-sewing machine, which sews books on tape without
cutting up head or tail--a most important improvement--and also forms
complete Kettle stitches, will sew books of any size up to 18 in. The
needles are straight, and the necessary adjustments for various sizes
of books are very simple.

Rounding and backing.

The machine for rounding and backing sewn books requires a rather
elaborate and very careful setting of several parts to the exact
requirement of each size to be worked. The sewn book with the back
glued is caught in a clip and forced between two tight rollers, the
result being that the hitherto flat back is automatically turned into
a rounded shape (figs. 10 and 11). The book is then drawn forward, by
a continuance of the onward movement, until it reaches the rounding
plate, which is a block of steel with a polished groove a little
larger than the size required. This rounding plate moves within a
small arc by means of heavy counter-weights, and on the back of the
book being strongly pressed against it, it receives the permanent form
of the groove cut in it, at the same time a strong grip on each side
of the book causes the ledge to rise up along each outer edge of the
back. This ledge it is which enables the boards to be subsequently
fixed in such a way as to hinge on a line outside the actual and
natural boundary of the book. Before the discovery of the possibility
of producing this ledge, the boards of books hinged upon a line
coincident with the inner edges of the back, the result of which was
that when t