Wool has some amazing qualities, all in one fibre, grown naturally:

The first thing to know about wool is that it is hygroscopic – a great trait for clothing and an equally great word for your next crossword puzzle or cocktail party. Hygroscopic means that the fiber is able to absorb up to 30% of its weight in moisture while still feeling warm and dry against your skin. This helps the fabric breathe, readily absorbing and releasing moisture to maintain a steady ecosystem of comfort against your skin, no matter how cold or damp the external weather may be.

Wool is naturally flame-retardant and has long been a favorite material for firemen’s blankets and industrial fabrics in public buildings. When exposed to flame, wool simply extinguishes itself without a peep. The constant level of moisture in the fiber keeps wool from conducting static electricity, which not only causes those annoying shocks but also acts as a magnet to pull fine dirt and dust particles deep into your garment.

Wool is also extremely resilient and highly extensible, which essentially means you can stretch a third of its length, or two-thirds when wet, and it’ll recover to its original shape. Despite over a century of effort, not a single manmade fiber yet possesses all these amazing qualities.

– C. Parkes, The Knitter’s Book of Yarn: The Ultimate Guide to Choosing, Using, and Enjoying Yarn, Potter Craft 2007, New York

Image © Susan Crawford and used with her kind permission. You can read some more about this vintage ball band in her Wovember2011 contribution.