“The fact is this;—the thinner the layers of stone are, the more beds of mortar they require between them; but if you have observed the thin stones in question you will have remarked that they are extremely rough and riddled, with cavities on their beds. There must be plenty of mortar between each course, to fill these rugosities and cavities well: and for that very reason masonry of this kind is excellent, if you are not sparing of mortar; and these rough surfaces adhere to the mortar much better than smooth surfaces could do: they become incorporated with it, and the whole soon forms one solid mass. But then you must not spare lime and sand, and that is why Branchu says this kind of walling swallows up a great deal of mortar.”
“Branchu also says that he has been finding stone good for making lime, above blocks of building limestone, and asks whether he is to put that aside.”
“Certainly if the lime-burner at the Mill cannot furnish us with lime, we will make it ourselves; this will not be difficult since we have plenty of firewood from the recent fellings.”
“Branchu also asked me where he was to put the excavated earth.”
“You will tell him to-morrow morning, to have it deposited en cavalier to the right and left of the excavations; we shall want it to level the approaches to the house.”
“What is a cavalier?”
Fig. 22.
“It is an artificial mound of regular breadth and height, so that its solid content can easily be calculated. Thus, when earth is removed from diggings with wheelbarrows,—and this is, as you see, the means we are employing,—we mark out the area this mound is to occupy on the ground, as at A B (Fig. [22]), representing the length, and C D the breadth. That done, the point B being farthest from where the excavation is going on, the wheelbarrow men deposit their first loads at B, leaving an inclined embankment not too steep for the barrows to be wheeled up it without too much labour. Thus by degrees an embankment, A E B, is formed. Then, from the middle F half way up the incline A E, they leave a road, a b, 5 feet wide for the barrows to go up and down, and then fill up the triangle, A G F, by inclined layers. Lastly, they fill the triangle, G F E. The road, g D h i, remains to be filled up, and the shovellers do this by depositing the soil on the road itself. The mound being thus perfectly regular, its slopes are produced by the running down of the soil—that is, they form angles of about 40° with the horizon, according to the nature of the embankment. The mound being finished, and measuring, say, 10 yards long at half its length from l to m, and 4 yards wide at half its height from n to b,—multiplying 10 yards by 4 yards we get 40 superficial yards at this mean level. Multiplying this number by 2 yards, the height of the mound, we get 80 cubic yards. You know therefore that this quantity of earth has been moved, and consequently, what you have to pay, if your cuttings and embankings are at so much per cubic yard, or what a cubic yard of soil removed costs you if you pay by the day.”
“This will give us the solid content of the excavation then?”