FREE Stone, a whitish stone, dug up in many parts of
Freehold of Britain, which is hard and durable, and of excellent use in building, &c. It is a kind of the grit stone, but finer sanded and smoother; and is called free, from its being of such a construction as to cut freely in any direction.
The qualities of the several kinds of free stones used in the different parts of Europe are very different. They all agree in this general property, indeed, that they are softer while in the quarry than when they have been some time exposed to the air: but even this general property differs greatly in degree. There is a sort of gray free stone in use at Paris (of which we do not yet seem to have met with any in this country), which has the above-mentioned quality in so great a degree, that the expence of working it is in a great measure saved.
This stone lies everywhere on the south side of the river Seine, and is of a coarse and large grit. It is so soft when newly taken out of the strata, that they fashion it very conveniently with a sort of broad axe, and form as many stones for building in this manner in an hour, as an equal number of our people do in a day or two. Though this stone is as soft as dry clay when first taken up, it is found to harden so considerably in the air, that it becomes more than equal to our ordinary free stone.
The Portland free stone of Britain of the finest kind, which is white and of a close grit, is very fit for hewing and carving; but it will neither resist water nor fire, which is a very singular instance in so dense a stone; while the free stone of Kent, which is less beautiful to the eye, and is of a grayish colour, and considerably close, though of a larger grain, resists the air and water very well. The freestone of Derbyshire, on the other hand, is so brittle as to be unfit for any fine working; and so coarse and open in its texture, that it lets water through: yet it bears the fire extremely well, and is fit for ovens, hearths, &c.