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Curious Discovery In Practical Science

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Inthegranite quarries, near Seringatam, the most enormousblocks are separated from the solid rock by the following neat and simple process. The workmen having found a portion of the rock sufficiently extensive, and situated near the edge of the part already quarried, lays jare the upper surfuce, and makes on it a ne in the direc:ion of the imended sepaation, along which a groove is cut with a chisel about a couple of inches in depth. Above this groove a Jine. of fire is kindled, and this is maintained til! the rock Üloyr is thoroughly heated on which a ine of men and women, each provided with a pot of cold wtfer, suddenly sweep off tbc ashes, and pourthe water into the leated groove, when the rock at once splits with a clean fracture. Square blocks of six feet in the side, and upwards ofeighty feet in Iength, are someiimes detached by this meihod. Hardly Iess simple and efficacious is the process used in some parts of Franco, where milistones are made. When a masa sufficiently large is found, it is cut into a round form several feet high, and the question then arises how to divide this into pieces of a proper size for milistones. For this purpose grooves are chiseled out, at distances correspondingtothe thickness intended to be ghen to the milistones, into which grooves wedges of dried wood are drivcn. Those wedges are i!:en wctted, or exposed to the night dew, and nest morning the block of stone is found separated into pieces of a proper size for milistones, merely by the expansión of the wood, consequent on its absorption of moisture ; an irresistable natural power tbüs accomplishing, almost without any irouble, and at no expense, an operation which, from t;e peculiar hardnessof the texture of the stone, would other-wise be impracticable but by the most powerful machinery ; or by the mo'st persevereing labor.