In the introduction to this chapter, some remarks were given intended to explain the various structural differences between these substances, and those noticed in the following group.

Freestone is a terra commonly applied by the mason to such of the sandstones used for building purposes as work freely under the tools; namely, the stone-saw, a smooth iron blade fed with sand and water, and the ordinary picks and chisels, which are too familiar to require more than to be named. The freestones arc frequently turned into balustrades, pedestals and vases, in the modes next adverted to.

Sandstones, from their relatively slight cohesion, may be turned with the point tool used for marble, although in the workshop, the grindstone is commonly turned with an old file drawn down for some two or three inches to about one-eighth of an inch square, and held downwards upon the rest at the angle of 20 or 30 degrees; it is rolled over and over, which continually produces a new point; the stone is then smoothed with a flat piece of iron or steel, or rubbed with a broken lump of another grindstone.