Related Clues:

• Outer space
• Flammable solvent
• Upper atmosphere
• -- alcohol
• Old sleep aid?
• Former anesthetic
• The wild blue yonder
• Old operating-room substance
• Inhalation anesthetic, once
• Chloroform substitute
• Heavens, poetically
• Old-time knockout
• Old hospital supply
• Word on old gas pumps
• Chloroform cousin