Make sure the plywood or concrete board pieces are dead level with each other; if they are not and are off just a bit, large tiles will tend to rock on an uneven seam when walked on and are bound to crack.
22.
The great principle which governs these plans is, to reduce the surface of the earth as nearly as possible to dead level . . . . The natural inequities of the ground are destroyed . and the existing water courses disregarded . . . . These are men who would have cut down the seven hills of Rome.
23.
Emerging from the chain of Blue Mountains, they descended upon a vast plain, almost a dead level, sixty miles in circumference, of excellent soil . . . In traversing this plain, they passed, close to the skirt of the hills, a great pool of water, three hundred yards in circumference, fed by a sulphur spring, about ten feet in diameter, boiling up in one corner.
