My first is in pleasure, but never in sleeping;
My next is in smiles, but never in weeping.
My third can be found in both lemons and limes;
My fourth is in moments, but never in time.
My fifth is in children, but not in their cries;
My sixth is in girls, but is never in guys.
My last is in peaches, and also in pears.
My whole, when you find it, is lighter than air!
What am I?
I think the answer is
"ammonia"
Each line in the riddle, except the last one, represents a letter from this word that follows the rules:
"a" is in the word "pleasure", but not in "sleeping"
"m" is in the word "smiles", but not in "weeping"
"m" is in both in the word "lemons" and in "limes"
"o" is in the word "moments", but not in the word "time"
"n" is in the word "children", but not in the word "cries"
"i" is in the word "girls", but not in the word "guys"
"a" is both in the word "peaches" and in the word "pears"
The last line in the riddle refers to the fact that ammonia is twice as light as the air.
