Answer:
Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around.
I turn around once. What is out will not get in. I turn around again. What is in will not get out.
What gets beaten, and whipped, but never cries?
The sharp slim blade, that cuts the wind. What is it?
In your fire you hear me scream! Creaking and whining yet I am dead before you lay me in your hearth.