One of the unique things about sheep's wool is that sheep produce lanolin, a waxy, oily secretion that helps the wool repel water. Nature's WD-40!
Those grayish-yellowish Aran Isles sweaters you see on the Irish fishermen help them to repel the mist and moisture while they work. Knitters can buy lanolin-oiled wool in various degrees of water resistance. The darker the wool, the more lanolin has been left in. The whiter the wool, the more it's been bleached out.
