ied up three or
four courses to a level with the guidance of the line which is raised
course by course, the work should be proved with the level and plumb-rule,
particularly with the latter at the quoins and reveals, as well as over the
face. A smart tap with the end of the handle of the trowel will suffice to
make a brick yield what little it may be out of truth, while the work is
green, and not injure it. The work of an efficient craftsman, however, will
need but little adjustment.

For every wall of more than one brick (9 in) thick, two men should be
employed at the same time, one on the outside and the [v.04 p.0522] other
inside; one man cannot do justice from one side to even a 14-in. wall. When
the wall can be approached from one side only, the work is said to be
executed "overhand." In work circular on plan, besides the level and
plumb-rule, a gauge mould or template, or a ranging trammel--a rod working
on a pivot at the centre of the curve, and in length equalling the
radius--must be used for every course, as it is evident that the line and
pins cannot be applied to this in the manner just described.

Bricks should not be merely _laid_, but each should be placed frog upwards,
and rubbed and pressed firmly down in such a manner as to secure absolute
adhesion, and force the mortar into joints. Every brick should be well
wetted before it is laid, especially in hot dry weather, in order to wash
off the dust from its surface, and to obtain more complete adhesion, and
prevent it from absorbing water from the mortar in which it is bedded. The
bricks are wetted either by the bricklayer dipping them in water as he uses
them, or by water being thrown or sprinkled on them as they lie piled on
the scaffold. In bricklaying with quick-setting cements an ample use of
water is of even more importance.

All the walls of a building that are to sustain the same floors and the
same roof, should be carried up simultaneously; in no circumstances should
more be done in one part than can be reached from the same scaffold, until
all the walls are brought up to the same height. Where it is necessary for
any reason to leave a portion of the wall at a certain level while carrying
up the adjoining work the latter should be racked back, i.e. left in steps
as shown in fig. 7, and not carried up vertically with merely the toothing
necessary for the bond.

[Illustration: FIG. 2.--Section of a Hollow Wall.]

Buildings in exposed situations a