[Illustration: CONCRETE CONSTRUCTION]

There is, however, a more decided difference between West's system and
those previously in use, for it is marked by the fact that the slabs
composing the shell of the whole structure in many cases may be built up
before the filling-in is deposited between the slabs, and in none of the
other cases can this be done. In fact, only in the first two cases
before mentioned can more than one course of slabs be laid before
filling-in of some kind must be done. Compared with the ordinary method
of building in concrete, this system avoids: 1. The charge for use and
waste of wood casings; 2. finishing the face of the work (both inside
and outside) after the structure is raised, and, therefore, the
bursting-off of the finished face; and 3. the difficulties encountered
in working mouldings and other ornaments on the face of the work by the
ordinary plasterer's methods. It also provides a face of any of the
usual colors that may be obtained in concrete, besides a facing of any
other material, such as marble, etc., and produces better and more
durable work, at the same time showing a saving in cost, especially in
the better classes of work; all of which is effected with less plant
than ordinarily required. For engineering work, such as sea walls, the
hexagonal slabs, made of greater thickness than those employed for
ordinary walling, will answer admirably, especially if the grooves be
made proportionately larger. By the use of these slabs the work may be
built up with great rapidity. For small domestic work, such as the
dwellings of artisans, these slabs; which are of such a form as to
render them easy of transport, may be supplied to the workmen themselves
in order that they may erect their own dwellings, as, on account of the
simplicity of this system and the absence of need of plant, any
intelligent mechanic can do the work.