fact, any other building material, may be used in conjunction
with the slabs.

The system of building construction is intended, as in the case with all
concrete, to supersede brickwork and masonry in the various uses to
which they have been applied, and, at the same time, to offer a more
perfect system of building in concrete. Hitherto slab concrete work has
never been erected in a perfectly finished state (i.e., with mouldings,
etc., complete), but has either been left in a rough state or without
ornament, or else has been constructed so as never to be capable of
receiving good ornamental treatment. Hitherto the great difficulty in
constructing concrete walls of concrete and other slabs has been to
prevent the slabs from being forced outward or from toppling over by the
pressure of the plastic filling-in material from the time of its
deposition between the slabs until it has become hard enough to form,
with the slabs, a solid wall. Besides the system of forming the slabs of
L (vertical or horizontal) section, or with a kind of internal buttress
and shoring them up from the outside, or of supporting the slabs upon
framing fixed against the faces of the wall, several devices have been
used to obviate this difficulty.

In the first place, temporary ties, or gauges, connecting the slabs
forming the two faces of the wall, have been used, and as soon as the
plastic filling-in material has set or become hard (but not before),
these have been removed. Secondly, permanent ties or cramps have been
used, and, as their name implies, have been allowed to remain in the
wall and to be entirely buried in the plastic filling-in material. These
permanent transverse ties or cramps have been of two kinds: those which
were affixed as soon as the slabs were placed in position, and those
which were made to form part of the manufactured slab, as, for instance,
slabs of Z or H horizontal section. Thirdly, a small layer of the
plastic filling-in material itself has been made to act as a transverse
tie by depositing it, when plastic, between the slabs forming the two
parallel faces of each course, allowing it (before filling in the
remaining part) to set and to thus connect together the slabs forming
each face of the wall, a suitable hold on the slabs, in some cases,
being given to the tie by a portion of the slab being undercut in some
way, as by being dovetailed, etc. As the slabs in this latter system
generally have wide bases, they may also