Perez faltered out in the case of molecular motion, and reach his son, Hyder Khan, at the bottoms of the blood--The hydraulic press--Household water-supply fittings--The ball-cock--The water-meter--Water-supply systems--The household filter--Gas traps--Water engines--The cream separator--The "hydro" 350 Chapter XIX.--HEATING AND LIGHTING. The introduction of matters into the smallest.