very often used in the present day, but with brick or stone quoins and footings to the walls, it is by no means a bad material, and in most places is less costly than either brick or stone. It might I think, with advantage, be used a little more frequently than is done at present; and probably great improvement might be made in the composition of the concrete of which mud walls are made. The addition of a small quantity of lime, where the price of lime is moderate, would make the material harder and more durable in most cases. In some kinds of building, concrete blocks formed in moulds have been used with economy and success, and it is possible that even in cottage building a similar plan might answer well. Mud walls are usually formed by ramming the earth and gravel which form the walls, in a wet state, into a wooden frame of the width of the intended thickness of the walls, and two or three feet deep; when filled, and the concrete sufficiently hardened, the frame is raised, and the walls carried up another stage.

Stone walls, where both stone and lime are abundant and reasonable in price, are less costly than brick, and, if properly built, are as good. They are usually sixteen or eighteen inches thick. It is of little importance whether they be built of stone as it comes out of the quarry, laid at random, or of dressed stone, laid in regular courses or otherwise; but it is absolutely essential in all kinds of stone wall, that there should be plenty of through stones-say two in every yard superficial of wall-and that the wall be entirely filled with small stone and soft mortar, or (which secures still better that the wall be free from

open

spaces inside) that it should be grouted.

Walls of stone at the outside and brick inside are better, but more costly, than those of stone only; and if the bricks which line the wall be hollow, so much the better.

But the material which is more generally used than any other for the walls of cottages, is brick alone. All the plans and elevations given herein are drawn for nine-inch brick walls with fourteen

inch work below the plinth. In the present day it is a common practice to build walls partially hollow. This is done, either by walling the common solid bricks so as to leave spaces inside the wall, or by using bricks which are made hollow.

Common bricks may be walled in a great variety of ways so as to leave open spaces inside the wall. The following are three of the commonest and perhaps the best ways of doing this : If the bricks be laid thus, a hollow

fourteen-inch wall

is obtained with

one-sixth more bricks than is required for a solid nine-inch wall. The bricks required to build a solid nine-inch wall, a hollow fourteen-inch wall, and a solid fourteen-inch wall, are in the proportion of 6, 7, and 9.

In this example

the proportion of

bricks in the three

kinds of wall is as 10, 12, and 15. In both

these kinds of wall a pretty good bond is obtained by laying the heading bricks in the second course over the headers in the first course, only from the other side of the wall; the result of this will be, that the open spaces will go the whole height of the wall. Solid courses may be mixed with these either alternately or otherwise, making the wall somewhat stronger, but more costly, in proportion to the number of solid courses used.

The next is a means sometimes used for build

ing a nine-inch wall with

hollow spaces in it. Every other course is formed of bricks set edgewise, as shown. This uses about one-fifth less bricks than a solid nine-inch wall, but is defective and weak, from there being nothing but the mortar to prevent the stretching bricks in the hollow course from being driven inwards.

I find a very peculiar mode of building hollow walls mentioned in some specifications from Southampton, as having been used in that neigh

bourhood with success. Two half-brick walls a few inches apart are tied together with bent-irons two feet apart every sixth course, as shown in the margin, in a vertical section of the wall. I know nothing myself of the merits of such walls, but can hardly think that they are much to be recommended. Hollow bricks, that is, bricks with two or more perforations through them, may be made in a common draining-tile machine; a variety of forms are made in different parts of England, some of which are so contrived, that the bricks on the two sides of the wall overlap one another, so as to form a kind of bond.

The partition walls on the ground-floor should in general be half-brick walls, and upstairs, either the same, or four-inch stoothing and lath and plaster. Mere boarding, although it is sometimes used, is hardly a sufficient division between two rooms. In the south of England half-brick walls are generally required to be strengthened by two or three tiers of hoop-iron