Related Clues:

• Fire was one thing to heat water
• He can stand for one, so can I, and so, from what we hear, can you
• He is one, and I too!
• Heating wire in iron, say
• Ingredient section of clientele mentioned
• Ecstasy left me in hospital department getting oxygen, say?
• Component that defies analysis
• Fundamental component
• Spain allowed to capture soldiers, creating suspicion
• He or I could be one
• Copper, perhaps, in part of cooker
• Basic substance that's used in heating
• Singular ingredient of the weather
• Component of periodic table
• Earth, air, fire or water