A cement which is proof against boiling acids may be made by a
composition of India rubber, tallow, lime and red lead. The India
rubber must first be melted by a gentle heat, and then six to eight
per cent by weight of tallow is added to the mixture while it is kept
well stirred; next day slaked lime is applied, until the fluid mass
assumes a consistency similar to that of soft paste; lastly, twenty
per cent of red lead is added in order to make it harden and dry.