In a large area of coke-breeze concrete flooring, the coke breeze should pass through a sieve of '-in. mesh, all larger pieces being broken smaller, and be retained on a sieve of 1/16in. mesh, all the dust that passes through being rejected. The proportions should be 2 1/2 parts of coke breeze, 2 parts of sharp clean sand, and 1 part of Portland cement. The whole of the materials should be carefully measured, and thorougbly mixed in a dry state. The water should afterwards be added slowly through a rose nozzle, and the materials turned over again at least twice to ensure thorougb mixing.