to some Parts of Italy.
The best Sand is that which being rubb'd between the Hands makes a little Noise, which that Sand does not, which is Earthy, because it is not rough. Another Mark of good Sand is, that when 'tis put upon any Thing that is White and shak'd off, it leaves no Mark behind.
The Sand which is dug out of the Earth has all these Qualities, and is esteem'd the best. Vitruvius makes four sorts of it; viz. White, Black, Red, and Bright like a Carbuncle.
If it happen that there be no good Place to dig Sand in, we may make use of Sea-Sand, or River-Sand, which is likewise better for Plastering than the Sand which is digged, which is excellent for Building, because it drys quickly. Gravel likewise is very good, provided the grosser Parts be taken away. Sea-Sand is worst of all, because 'tis long adrying; and for this Reason, where 'tis made use of in Building, they are forc'd to desist sometimes till it dry.
The Sand which is found near Naples call'd Pozzolana is so proper to make good Mortar, if it be mixed with Lime, that not only in the ordinary Fabricks, but even in the very bottom of the Sea it grows into a wonderful hard Body. In Old Times they made use of it for Moles or Ports of the Sea, for after having made with Piles and Boards a Partition, they fill'd up the whole Compass of the Partition with this Mortar, which dry'd of it self in the middle of the Water and became a solid Body.
THE first thing we should have a Care of before we begin to build, is, to have the Stones dug out of the Quarry before they be used, and to expose them in some open Place, to the end that those which are endamaged by the Air, during this Time, may be put in the Foundation, and those that prove Durable and Good may be kept for the Walls above Ground.
We must likewise have a great care of the Wood which we make use of; That it be cut in a seasonable Time, which is in Autumn and Winter; for then it is not full of that superfluous Humidity which weakened it in dilating its Fibers, but it is firm and well closed by the Cold. This is so true, that the Wood of Trees which grow and become very great in a little Time, by reason of their great Humidity, is tender and apt to break, and very unfit for Building Which Experience shows us particularly in those Firrs call'd Supernates, which grow in Italy, on that side the Apennine, towards the Adriatick-Sea, for they are great and beautiful, but their Wood is not good for Building; whereas those on the other side of the Mountain, which are exposed to Heat and Dryness, call'd Infernates, are very good for Building.
This superfluous Humidity endamages Trees so much, that we are sometimes constrain'd to make a hole at the foot of the Tree and let it run out, which is the occasion of the Practice which is observ'd in cutting of Wood for Building, to Tap that Tree at the Foot, cutting not only the Bark, but even some part of the Wood it self, and so leave it for some time before it be Fell'd.
It is likewise easie to judge of what great Importance the draining of this superfluous Humidity is for strengthning Lib. 1.
Chap. 5. the Timber, and hindring Corruption, from this, That those Piles which are interlaced among the Stones in the Walls and Fortifications of Towns endure for ever without Corrupting, when they have been burnt a little on the outside.
Lib. 1.
Chap. 11.
Lib. 2.
Chap. 8. Bricks ought not to be made use of but in very thick Walls; for this reason they did not build with Brick in Rome, for to save Ground; they were not permitted to make the Walls of their Houses above a Foot and a Half thick, which Makes about 16 Inches and a half of our Foot.
They likewise never made the top of their Walls with Brick; for the Brick of the Ancients not being baked, this part of the Wall would have been easily endamaged; for this reason they built it with Tiles, a foot and a half high, comprizing the Cornish or Entablature which was made likewise of Tiles to cast off the Water and defend the rest of the Wall. They likewise chose for these Cornishes the best Tiles, viz. those that had been long on the top of the Houses, and given sufficient Proof that they were well baked and made of good Matter.
The Walling with Brick was so much esteem'd among the Ancients, that all their Fabricks, as well publick as private, and their most beautiful Palaces were built with them. But that which principally made this sort of Building be esteem'd, was its great Duration; for when expert Architects were called to make an Estimate of Buildings, they always deducted an 80th. part of what they judged the Building cost for every Year that the Wall had been standing, for they supposed that the Walls could not ordinarily endure more than Fourscore Years; but when they valued Buildings of Brick, they always valued them at what they cost at first, supposing them to be of an Eternal Duration.
To make the right use of Lime and Sand, and to make good Mortar of them, it is necessary that the Lime be first well Quench'd, and that it be kept a long time, to the end that if there be any Piece of it that is not well burnt in the Kiln, it may, being extinguished at leasure, soften as well as the rest. This is of Great Importance particularly in Plastering and Works of Stuck, which is a Composition of Marble finely beaten with Lime. For if any little Pieces remain that are not well baked, when they come to be made use of, they crack and break the Work.
The way to know whether the Lime be well Quench'd, is thus: You Lib. 7.
Chap. 3. may thrust a Chip of Wood into it or a Knife, and if the Chip of Wood meet with any Stones, or that the Knife comes out clean without any sticking to it, it signifies the Lime was not will burnt; for when 'tis well Quench'd, it is Fat and will stick to the Knife; but the quite contrary happens to Mortar, for it is neither well prepar'd, nor well mix'd, if it stick to the Trowel.
For to make the right use of Lib. 2.
Chap. 4. Sand, you must first consider what it is to be employ'd in; for if it be Mortar for Plastring, you must not make use of Sand that was lately dug out, for it drys the Mortar too fast, which cracks the Plastring; but quite contrary if it be to be employ'd in Masonry, it must not have been a long time expos'd to the Air, for the Sun and the Moon do so alter it, that the Rain dissolves it, and turns it almost all into Earth.
Lib. 2.
Chap. 5. The Proportion that Sand and Lime ought to have to make good Mortar, should be three parts of Sand that is dug, or two parts of River-Sand or Sea-Sand against one of Lime, and 'twill be yet much better, if you add to the Sand of the Sea and the River a third part of Tiles well beaten.
Lib. 7.
Chap. 3. One of the Principal Things that is to be observ'd in making Mortar, is, to mix it well. The Grecian Workmen were so careful of this, that they Tewed it a great while, putting Ten Men to every Vessel wherein they wrought it, which gave so great a hardness to the Mortar, that when any big pieces of Plaster fell off the Old Walls, they made Tables of it.
Lib. 6.
Chap. 11. THE Foundation is the most important part of the Fabrick; for the Faults committed in it cannot be so easily remedied as in other parts.
To lay the Foundation well, you Lib. 1.
Chap. 5. must dig till you come to solid Ground, and even into the solid as much as is necessary to support the Weight of the Walls; it must be larger below than above the Superficies of the Earth.
Lib. 3.
Chap. 3. When you have found firm Earth to make it more solid, you must beat it with a Rammer; but if you cannot arrive at solid Earth, but
