A Useful Cement

Alum and plaster of Paris, mixed with water and used in the liquid state, form a hard composition and a useful cement.

Cement For Marble

Stir to a thick batter with silicate of soda, 12 parts Portland cement, 6 parts slaked lime, 6 parts fine lead, 1 part infusorial earth. This is very excellent for marble and alabaster. The cemented objects need not be heated. After twenty-four hours the fracture is firm, and the place can with difficulty be found.

Cement Mortar

About 8 parts of furnace ashes, slag, or coke, 4 parts of slaked lime, and 1 of clay, are taken and mixed dry, so as to form a cement, which, on mixing with water, sets in the ordinary way. The proportions of the materials may be varied so as to produce either an aerial or hydraulic cement.