National boilers, radiators, and specialties: catalog no. 26 (1920)
National Radiator Company · National Radiator Company · leaf 63
air valves are of the best workmanshipand finish. The threads are tapped with care and precisionand are tapered, insuring perfectly tight joints. The Novus Automatic Air Valve isthe best competition valve on the mar-ket. The composition carbon is thebest made and is drilled through thecenter,… … 64 NATIONAL HEATING SPECIALTI ES The Solus Perfect Automatic Air Valve
