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Subject
- Rare earths[remove]39
- Rare earth industry24
- Scientific illustration20
- Incandescent gas-lighting19
- Lighting11
- Auer v. Welsbach, Carl (Auer von Welsbach), 1858-192910
- Scientific apparatus and instruments10
- Welsbach Gas Light Company10
- Machinery8
- Chemical elements7
- Incandescent lamps7
- Periodic law7
- Periodic table of the elements7
- Gas-lighting6
- Incandescent gas-lighting--Fixtures6
- Interior lighting4
- Advertising3
- Cathode ray tubes3
- GTE Sylvania Incorporated3
- Incandescent lamps--Filaments3