okay stupid question...

Prompted by my desire to have a Victorian bathing suit, Next year's plans for Costume College, and the fabric.com wool sale amoungst other things.
What kind of wool exactly are Victorian bathing suits made out of?
I thought wool did evil shrinking and felting like things when it got wet.... so why were all, (okay may not be all but this is what my research as of now is showing me) made of wool. So confused.
Please oh LJ brain trust HELP!!!!!!!!!!!!!!!!!!!!!