Weak and strong Bricks.

quite as close as any new.

163

And if bricks are inclined

to tear asunder under any force enough to overcome the friction and sticktion' of ordinary good mortar the extra bit of mortar in the hollows would not hold it. The real reason I have no doubt is to save some material to the brickmakers. It has long been known that hollowing the beds' of stone to make the edges close weakens it enormously, so much as to crush the edges, and the practice is accordingly abandoned. And though the hollows in bricks are smaller in proportion, there can be no doubt, and indeed it has been proved by experiments, that a wall built of such bricks is weaker than when they are solid and have a flat bearing. It may be thought that no such a thing as the actual crushing of the bricks in a wall ever happens; but I happen to have sad experience that it does; for two houses of an institution of which I was treasurer had to be rebuilt because a dishonest builder about 100 years ago had used soft bricks which had begun to crush into dust, and so cost us about 8000l. by saving himself perhaps fifty.

Some architects are not content without having special bricks made, either smaller or redder or in some other way different from usual, which are always more expensive; and most uniform-coloured bricks are by no means always the hardest; perhaps it would be nearer the truth to say they never are, as they are apt to be underburnt, and I have seen them decaying in a few years in one of the most extravagantly built houses that I know. In some parts of the country all the white bricks perish while the red do not; and possibly the converse may hold elsewhere. They are made of different clay. The common yellowish 'stock' brick of London clay when well burnt is said to be the strongest

164

Moulded and Wood' Bricks.

of any, though a very ugly colour. I refer to what I said at p. 41, as to the incompatibility of white bricks with any good architectural effect when you are near enough to see what they are. It is however well worth while to have what they call 'purpose-made' red bricks, instead of the common 6 square' ones, for window jambs, cornices under eaves, and other places where moulding can be appropriately introduced and stone would be too dear, and I am glad to see that practice is reviving for it was used with very good effect in old Gothic houses in districts where stone was too expensive. I have lately been doing it myself, in a house not Gothic.

The importance of laying hoop-iron bonds in walls is too well known now to need dwelling on, especially over openings and round bays and apses. What are called wood bricks are generally required in specifications to be built into the walls, to nail door jambs and other woodwork to. But such thick pieces of wood first swell with the damp and then shrink and are loose. I have seen them quite loose and out before the walls were plaistered. A very good builder first told me this, and that thin pieces occupying the space of the mortar instead of the brick are thick enough to nail to and never come loose, and I find it is so.

Ashlar. There are a few points worth noticing as to the mode of executing stone work. It varies in external character, from rough walling of stones only self-faced, as it is called, i.e. not dressed with any tool, up to the finest rubbed stone. When the stone is dressed at all and laid with flat thin beds of mortar it is called ashlar, a word of which I never saw any satisfactory derivation. The most important practical point to be considered there is the depth to which these

Ashlar and Rubble walling.

6

165

facing stones should go. It is usually specified that they are to be 7 or 8 inches deep on the average;' for of course they ought to vary in depth to make the bonding hold. Now here is just one of those defects in specifying which nobody would discover without experience, but which architects ought to have found out and guarded against long ago, but apparently they have not. On the average' of what? If you go upon the wall and all the stones you can see manifestly short of the 7 or 8 inches on the average of them, the builder or his foreman has the ready answer, O, but the stones of the last course were much deeper, and so these will be all right on the average.' Of course they were not; but it is not everybody who will challenge him to take some off anywhere he likes, to let you see: which challenge will certainly be declined. The fact is that the expression is wrong and only calculated to encourage bad building and deceit : it ought to be, ‘on the average of every 5 or 6 feet of every course,' and then the clerk of the works or architect (when he comes) can see at once anywhere whether the work is being done properly or not.

In connection with that, the filling in' with rough stones or bricks is very often simply scamped, and they are merely loose rubble or brick-bats flushed with 'drowned' mortar. In this respect it must be confessed that our Gothic ancestors were great sinners, and consequently many of their walls have fallen, and especially their towers, as that of Chichester Cathedral did in 1861 and St. Albans was on the point of doing; and the Doncaster tower fell upon its knees when the outer casing of its legs was burnt. If they had been solid. throughout it would have stood. The old builders relied upon the immense thickness of their walls, and

166

Rock-faced Walls.

also expected their grouted rubble inside to become more solid than it did. It is essential to the security of walls that have to carry much weight that they should be built of flat-faced stones or bricks throughout, so that there may be no bursting pressure without relying on the mortar. Roundish stones between two ashlar faces are really very little better than fluid, except so far and so long as the mortar may keep them together. Not only the piers but the walls of towers containing heavy peals of bells should be built throughout of large squared stones.

Random Walling, in which the joints are not horizontal and vertical, but anyhow, looks picturesque, and may do well enough in long walls which form a continuous abutment and have no great weight to carry; and the same of flints. But they depend entirely on the mortar for their strength, and have practically no bond at all, especially as the stones are generally somewhat wedge-shaped inwards, and therefore under a constant pressure outwards. Mechanically that can only be pronounced a very weak kind of building. Some of the old flint work in the eastern counties has been done so well and with such good mortar that the walls are almost like 'plum pudding stone,' a kind of natural concrete of the hardest kind. Other specimens of it, when the mortar has been bad, are as rotten internally as the worst modern work.

'Self-faced,' or as it is sometimes called 'rock-faced' walling is used a good deal in so-called Gothic buildings now of a plainish kind, and I do not know that it can be reasonably condemned. At the same time it was never used in real Gothic, except for the roughest kind of walls, or when it was intended to be plaistered; which Gothic buildings were a great deal more com

Rubbed Stone-work.

167

monly than is allowed by our architectural prigs and inventors of maxims founded on no real experience, a breed of men by whom every art and business and profession has become infested.

There is a wonderfully absurd imitation of natural or rock-faced stone in what is called the rustic basements' of the Renaissance style, in which far more trouble is taken to work the stone with small chisels into artificial roughness than it would take to work it smooth, and ten times more than it would take to 'boast' (as they call it) into a fairly level surface. The opposite extreme to that is rubbing' into the smoothest surface that the stone will take. Hundreds and thousands of pounds have been spent on that folly; for it is nothing else, even in the styles of architecture to which smooth surfaces are most appropriate, inasmuch as it cannot possibly last long, whether the stone decays, as in nine cases out of ten, or preserves itself by vegetation on the surface, as it may do if it is lucky, and tolerably free from smoke. It took modern architects many years to find out or to admit that smooth rubbing is absolutely fatal to Gothic effect: indeed very few of them have found it out yet to any practical purpose; for the drag, which is a kind of smoothing file' in the form of a scraper, is almost invariably used for final spoiling of the work inside, and very often outside too, in order to make a church or other building look neat and pretty for the opening.

Marble is a different thing in this respect, because its effect depends on the variety of its colour, which does not come out without polishing. It is singular that all obviously careful working of stone is injurious to its effect, and yet it is wonderful how difficult it is to prevent it, because the much vaunted working man,