When the corners of a marble clock-case are broken off, the disfigurement may often he remedied by reducing the case, after which the polish may be restored. The procedure is as follows. File off from the damaged part as much as may be necessary, taking care, however, not to alter the original shape of the case. Then grind off the marks of the file with a suitable piece of pumice-stone with water, and then with a water-stone, giving special attention to the corners and contours. Moisten a hard ball of linen and sprinkle over it either tripoli or line emery, and with this rub up a lustre; then rub with a linen ball, using with it finely washed emery and rouge; when dry, finish the polishing with a mixture of beeswax and oil of turpentine. This method may be used for all sorts of marble. When the piece broken off is too big, or when the fractures are too deep for the above plan to be adopted conveniently, the damaged parts may be made up with a cement prepared by mixing finely powdered marble with a little water glass. This is appliedin the form of a thick paste, and, when dry, has its shape corrected by filing, a polish being obtained as recommended above.

Parts broken off a coloured marble case may be cemented in place again by wetting the pieces with an aqueous solution of silicate of potash, putting them into position, and allowing forty-eight hours for the cement to dry. For white marble, egg albumen with a little Vienna lime forms the cement.