ipulated in schedule I. of London Building Act 1894. Many English
provincial authorities in determining the thickness of a cavity-wall, take
the outer portion into consideration.

In London and the surrounding counties, brickwork is measured by the _rod_
of 161/2 ft. square, 11/2 bricks in thickness. A rod of brickwork [Sidenote:
Materials and labour.] gauged four courses to a foot with bricks 83/4 in.
long, 41/4 in. wide, and 23/4 in thick, and joints 1/4 in. in thickness, will
require 4356 bricks, and the number will vary as the bricks are above or
below the average size, and as the joints are made thinner or thicker. The
quantity of mortar, also, will evidently be affected by the latter
consideration, but in London it is generally reckoned at 50 cub. ft. for a
1/4-in. joint, to 72 cub. ft. for a joint 3/8 in. thick. To these figures
must be added an allowance of about 11 cub. ft. if the bricks are formed
with frogs or hollows. Bricks weigh about 7 lb each; they are bought and
sold by the thousand, which quantity weighs about 62 cwt. The weight of a
rod of brickwork is 131/2-15 tons, work in cement mortar being heavier than
that executed in lime. Seven bricks are required to face a sq. ft.; 1 ft.
of reduced brickwork--11/2 bricks thick--will require 16 bricks. The number
of bricks laid by a workman in a day of eight hours varies considerably
with the description of work, but on straight walling a man will lay an
average of 500 in a day.

The absorbent properties of bricks vary considerably with the kind of
brick. The ordinary London stock of good quality should [Sidenote:
Varieties of bricks.] not have absorbed, after twenty-four hours' soaking,
more than one-fifth of its bulk. Inferior bricks will absorb as much as a
third. The Romans were great users of bricks, both burnt and sun-dried. At
the decline of the Roman empire, the art of brickmaking fell into disuse,
but after the lapse of some centuries it was revived, and the ancient
architecture of Italy shows many fine examples of brick and terra-cotta
work. The scarcity of stone in the Netherlands led to the development of a
brick architecture, and fine examples of brickwork abound in the Low
Countries. The Romans seem to have introduced brickmaking into England, and
specimens of the large thin bricks, which they used chiefly as a bond for
rubble masonry, may be seen in the many remains of Roman buildings
scattered about that country. During the reigns of the early T