Horse-manure
A means for conveying gases from the loam used for building and coating the moulds and cores. The quality of sands and mixtures employed for this purpose is necessarily hard and unyielding, having little porosity, and must therefore be rendered porous by artificial means. Besides imparting porosity, the manure possesses a quality of stickiness which renders the sand or loam more cohesive, and it is for this reason that it is to be preferred to other substances, as coke-dust, sawdust, etc., which are frequently used for this purpose. See LOAM; FACING-SAND; VENTING.