cement mill (sementmil)

A mill for crushing the stony concretions from which a form of cement is obtained. 'ston), n. Any rock cement-stone (se-ment' which is capable of furnishing cement when properly treated. Most of the rock used in the United States for cement comes from the Tentaculite division of the Lower Helderberg series, and the product takes the name of Rosendale cement from the town of Rosendale in Ulster county, New York, where it is chiefly worked. The rock which furnishes cement is a more or le impure limestone, or mixture of carbonate of lime with sand and clay. Pure limestone will not make a mortar which will set under water; but some magnesian limestones have hydraulic properties. The theory of the hydraulicity of cement is not clearly understood, although much has been written in regard to it. Also cement -rock.