Answer:
What is the thing which, once poured out, cannot be gathered again?
What is long and slim, works in light. Has but one eye, and an awful bite?
Although my cow is dead, I still beat her. What a racket she makes!
In Paris but not in France, the thinnest of its siblings.
What is weightless but takes two people to hold it?
You use it between your head and your toes, the more it works the thinner it grows.