MILLSTONES. The millstones employed in grinding corn require to be made of a peculiar kind of stone. The greater proportion of our millstones are procured from a par-1 ticular spot in Western Germany. At about ten miles from Coblenz is a small town called kndernach, the chief trade of which is in millstones procured from the o.neighbouring quarries of Nieder•Mendig. There are several quarries, averaging about 50 feet in depth, each quarry shaped like an inverted cone, down o the sides of which the quarry men descend . by a spiral path. The quarry men have to ; cut away through a superincumbent layer of ; soft porous stone, till they come to a layer of o hard, blackish, heavy stone, regularly porous, and yielding sparks when struck with iron. - This is the mill-stone, and requires good and • well prepared tools to work it ; it is supposed to be a compact lava from some extinct volcano; and as there are fissures or gaps at intervals, these facilitate the separation of the stone into blocks suitable for millstones. All round the bottom of the conical cavities, the stone has been excavated in galleries or horizontal , passages. The stones are brought to shape by means of hammers and chisels. A deep
socket is cut through the middle of such stones as are intended for runners, or upper stones. The furrows on the surfaces of the. stones are I produced by means of a double edged hammer, about 111hs. weight.
The hard volcanic stratum from whence the millstones are cut, extends five miles in length by three in breadth ; so that the supply may for all practical purposes be deemed inex haustible. It is known that millstones have been procured from this spot during a period of 2,000 years. Four or five families usually unite in the labour of sinking a shaft and working the stone ; all assisting in the labour according to their strength and ability. The workers divide themselves into four groups —the miners, the lifters, the cutters, and the loaders. When the millstones are properly shaped, they are sent down the Rhine upon the immense timber rafts which navigate that river. When the rafts arrive at Holland, they are broken up for the sale of the timber ; and the millstones are distributed in various quarters according to the demand.