Answer:
It cannot be seen, it weighs nothing, but when put into a barrel, it makes it lighter.
My first is equality; my second is inferiority; my whole is superiority.
I am a span of time you can always see through I am also the timepiece with the most pieces. What am I?
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
I'm flat. You use me everyday. You need me to live. But you give me away everyday. I'm coloured and I have a founding father on me. What am I?
You use it between your head and your toes, the more it works the thinner it grows.