Related Clues:

• Early number?
• Number three substituted
• Air, poetically
• Clear night sky, in poetry
• Number used no more?
• Highly flammable liquid once used as an anaesthetic
• Number one from one of two
• A number rule the roost, to some extent
• Solvent; clear sky
• Old number — some leave the room
• I'm volatile in that place, the first to rise up
• Some chose the right anaesthetic
• What radio signals travel through, with 'the'
• Old dentist's supply
• Anaesthetic liquid; clear sky