form is, of course, the best. Boys are not now sent up flues for sweeping purposes, therefore there is no object in retaining the oblong form, but as the circular form is not readily constructed in brickwork, a square flue seems to be practically the best form, as it is more readily and efficiently swept with the circular brush.

The Metropolitan Building Act provides that all flues shall be parged, or pargetted inside-that is, plastered. This I, however, very strongly object to. It is in my opinion but encouraging bad work, as the bricksetter is certain to take less care in building the flues and filling the joints if he thinks it is to be plastered over. This is but natural. The plastering, unless it is done in the best manner and with the best materials, decays and falls off in patches down the chimney to the great disgust of the occupants, and the soot also lodges in these places. Then the smoke finds its way through the open joints of the brickwork into the house, more particularly between the joists.

All flues should be built with good straight bricks, as carefully as any other part of the building which is intended to be seen, and the joints filled in solid and then struck with a small trowel, as if for whitewashing, and great care should be taken to tie the midfeathers into both the back and front walls every few courses; this last is often neglected.

The grouting of the walls I also always object to, as, if recognised, it generally means building the back and front faces four or five courses high, half-brick thick, with good bricks, and filling in the inside with bats and rubbish, then pouring in from a bucket a thin mixture of mortar and water of the consistency of thick soup, which, even if it is fortunate enough to find its way into all the joints, but fills them with a very imperfect character of material. This you can readily understand, as the grouting must be thin, or it will not reach the joints, and when the water evaporates, or forces its way through a joint and escapes, what remains will be at the best but a sort of honeycomb without strength or capability of turning damp.

Brickwork should be built course by course, of good whole bricks, any closers being cut the full size required, and all the parts flushed full with mortar. No grouting should be required, nor any attempts to force the mortar into the joints with the edge of the trowel, which will not succeed. The nearer you can get to this class of work the better.

Before leaving brickwork I will mention two other things—one

is, that very great care should be taken with work where two kinds of materials are used, as, for instance, common brick walls faced with stock bricks, the stock bricks being set very close, and with carefully-prepared mortar or putty, and the backing of rougher bricks set with joints about -in. thick of common mortar. Now, generally, in the cheaper class of property, a large proportion of the stock brick headers are cracked off, so that this makes practically two walls. Very often the inner backing compresses or sinks more than the out facing and the stock brick bulges out, either separating itself from the inner work or carrying with it the inner work.

The same applies to the backing behind stonework, which should be carefully built of good bricks and laid in quick setting mortar or cement. I have often noticed the backing to piers (when it has been half-brick and one-brick thick) quite loose, and in a few

Brick backing to

stonework.

cases have taken it down and replaced it with brickwork in cement. But, when practicable, in small piers the stonework should pass through the wall; there is really no excuse for backngs of one-brick thick only; the cost of the extra stonework would be very trifling. You will see the importance of this matter if you will look at a pier built of stone, say ten feet high of ten stones, and say with ten joints, counting the bottom one. Now we know that masons, as a rule, are careful in making the beds of their stones level and straight, and in setting the work with close joints; in fact we may assume that the stone, by its own weight, will come down close, immediately, but certainly before the bricklayer commences to back up. Now, take the joints in the ten feet of brickwork and you will have about forty joints, averaging nearly 3-in. each, or about 15-in. of mortar, which remains soft for some time and liable to be compressed if any weight is placed upon it.

You can therefore readily see how important it is if you are to have sound work, that the back part of the wall should be cf such materials as will ensure its being as sclid as the front part.

In masons' work there will be less to explain than in brickwork. Generally the same conditions apply to the bedding of stonework, so far as the joints being fully and completely filled with mortar. This, you will readily imagine, must be of importance when you have true and neatly dressed joints or surfaces to deal with, such as is generally the case in stonework, especially where through stones occur. It is necessary that stone walls should be built with a cavity, if they are expected to be dry, particularly if at all exposed to driving rains, otherwise the water will pass through them. The great thing to be attended to in stonework is to see that the facing stones are thoroughly tied into the backing, whatever it is-brickwork or rubble. Proper through stones should be provided, and plenty of them, and the remainder of the facing stones should be not less than six inches on the bed. I have seen them used varying from six inches to three inches in bed, but this should not be allowed.

In rubble work, the stones should be of fair size, and should be laid so as to bond and work into one another, the object being to keep the wall together-to hook, as it were, one stone into another, so as to prevent the wall from separating. The small angle spaces should be filled with pieces of stone as large as can be placed there, and care taken that each piece of stone shall be solid, and shall not rock. You want the wall to be of stone, not mortar; but you should have the mortar put in first, and the stone pressed in afterwards. By this you will ensure solid work.

Again, great care should be taken that the stone, most of which used for building purposes is stratified or laminated like the leaves of a book, shall be placed on what is called its natural bed—that is, with the strata or leaves horizontal, in the same way that it was formed in the quarry. If this is not done, the action of the air in most cases will cause the laminæ or strata to separate and fall away. This you will see in numberless instances in buildings where certain stones have been, as it were, eaten away for some inches in depth. There is no means of stopping it wherever it commences that I am aware of, though many attempts have been made, and ultimately the stones will have to be cut out and replaced. Stones should be marked on the top side at the quarry, so that the same position may be retained in the work. I would particularly direct your attention to defects in stone, and this is of very great importance to workmen.

Before the workman commences, he should examine the stone

itself, and see if there are any defects in it which will show after it is worked; if there are, he should call the attention of the foreman to the defects, and, as he proceeds with his work, should other defects be exposed, he should at once stop and call attention to them. Otherwise, when possibly he has expended some pounds' worth of labour on the stone, it may be condemned. I have often noticed this, and have had to condemn stones when a little thought on the part of the workman would have saved his employer some pounds: the stone, as a rule, is not wasted; if it will not do for this particular purpose, it will cut up for something else; but possibly after it is worked it may be useless; a little thought would tell you that it would not be allowed to be used, and if overlooked at the time would, if found out, have to be cut out of the building and replaced at considerable expense. remember once having to discard one of two large gate-posts, something like three feet square and seven or eight feet long. As soon as they were delivered they were propped up from the ground ready for working, although a heavy frost after rain had just set in. Directly I saw them, I ordered them to be dropped on to the ground and covered, but I was too late with one, which was ultimately found to be cracked, but attention was not drawn to this by the workman until the stone was nearly completed, although he knew it. The consequence was a delay of some weeks' time in completing the work, and a loss of many pounds in money to the contractor.

I

The beds of stonework which rest on brickwork should be attended to better than is usually the case. Very often the idea seems to prevail that the quarry scappling is sufficiently good for this purpose, and the stone is fixed and packed up with bits of slate, or stone or brick, as may be required, to bring it to its proper position. This is a great mistake, as upon this bed the entire weight of the superstructure rests. The fact of its not being exposed to view should not be considered at all.

Cramps and dowels are a very important part of a mason's work, and it should be remembered that metal which has any tendency to corrode should not be used in these, or if used should be carefully protected. Copper or zinc may be used, or thick slate cramps if there is sufficient substance in the stones to admit of their being formed of proper size, and they should be sufficiently long to avoid the usual bursting off of the portion of the stone gripped by the cramp. Dowels are the same;

they should either be of copper or of slate, but never of iron. The peculiarity of iron is that in rusting, when enclosed in a stone it is not eaten away, and does not get smaller, but throws out a skin or oxide with irresistible force. You may therefore, almost in any

SLATE CRAMP.

old building where iron dowels have been used, see pinnacles and shafts split, and if you get at the dowels you will find them swelled beyond the original size.

Care should be taken with throatings to sills and all other projecting portions of stonework. In many cases these are made in the most slovenly and insufficient manner, being little more than a scratch or line. They should be clearly cut and of fair depth, never less than from in. to 3-in.

斤

Throating to stonework.

Coming back again to the subject of the lower part of the building, I would suggest to you the advisability of using in ordinary