 In 1820, Hancock rented a factory in Goswell Road, London, where he worked raw rubber with the machines he had invented.His machines produced a warm mass of homogeneous rubber that could then be shaped and mixed with other materials, and was more easily dissolved than raw rubber.The prototype of his masticator was operated by one man and could only hold ; it was a wooden machine with a hollow cylinder studded with metal "teeth", with an inner studded core that was hand-cranked.