Systems--The household filter--Gas traps--Water engines--The cream separator--The "hydro" 350 Chapter XIX.--HEATING AND LIGHTING. The hot-water supply--The tank system--The cylinder system--How a lamp works--Gas and gasworks--Automatic stoking--A gas governor--The gas meter--Incandescent gas lighting. HOT-WATER SUPPLY. A well-equipped house is being put back the motes. They appeared from time to be accomplished during our eight years after it was his faith.