sentences:  Amongst these were James Frost who had about twenty patents from 1811 to 1822 including one for "British Cement" and in 1824 Joseph Aspdin, a British bricklayer from Leeds, with his now famous patent for a method of making a cement he called "Portland cement".This was done by adding various materials together to make an artificial version of natural cement.The name "Portland cement" is also recorded in a directory published in 1823 being associated with William Lockwood, Dave Stewart, and possibly others.