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Circle divided into equal parts by concentric circles.

Dividing Circle into Equal Parts by Concentric

Circle divided into equal parts by concentric circles.

"The plate A is 46 inches in diameter, and is composed of gun metal. These were put on by original graduation, mainly on the plan of Edward Troughton. One very great improvement in this engine is that the axis B is tubular, as seen at C. The object of this hollow is to receive the axis of the circle to be divided, so that it can be fixed flat to the plate by the clamps E, without having first to be detached from the axis and other parts to which it has already been carefully fitted. This obviates the necessity for resetting, which can hardly be done without some error. D is the tangent screw, and F the flame carrying it, which turns on carefully polished steel pivots. The screw is pressed against the edge of the plate by a spiral spring acting under the lever G, and by screwing the lever down the screw can be altogether removed from contact with the plate." — Encyclopedia Britannica, 1893

Dividing Engine

"The plate A is 46 inches in diameter, and is composed of gun metal. These were put on by original graduation,…