129,808. British Refrigerating Go., and Jodrey, E. W. July 17, 1918. Thermometers. - In a combined temperature and pressure indicating gauge for use with a vessel in which gas or vapour is distilled from solution by heating, the temperature and pressure pointers g<1>, d<1> which move over the same dial g, are arranged to aline when the specific gravity of the solution has reached a predetermined value so that at this critical point the heating may be stopped to avoid excessive evolution of water vapour. Mechanism operated automatically by the temperature or pressure pointer may control a valve such as l in the fuel supply pipe to the burners.