Here are some geeky but useful sites about bow hair–why we use horsehair, how rosin works, different kinds of hair, etc:
Splitting Hairs
Study on Violin Bow Hair (also applies to bass)
Here are some general sites about the bow and how it works:
How the Bow Produces Sound
The Art of the Bow
General Bow Info
A Bow on the Couch
Bass News Right To Your Inbox!
Subscribe to get our weekly newsletter covering the double bass world.