Related Clues:

• Scientific discovery of 1898
• Cinephile's collectible
• Plymouth model
• Broadway luminary?
• Odorless gas
• Ginza night glow
• One of the noble gases
• Dodge model
• None can alter this element
• It's a gas!
• See 56-Across
• Glass tube filler
• Advertising element
• Cryogenic refrigerant
• Gas for the theater district