Many of us associate wool with sheep, but other mammals — including alpacas, camels and goats — also produce fibres that can be twisted into yarn and then textiles.
It’s possible humans started making wool after noticing that, as the fibrous hairs were scraped from the hide of an animal, they twisted together easily into lengths.
Wool fibres — made mostly of alpha-keratin, which is found in all mammalian hair as well as horns and claws — stick together easily. The cells of their outer layer, or cuticle, have evolved to overlap like tiny shingles, creating spots for one fibre to catch on another as they are twisted.
Clothing and other items made of wool have been found throughout much of the ancient world, from 3,400-year-old Egyptian yarn to fragmentary textiles unearthed in Siberian graves dating from the first century B.C.
The process of making wool fabric from fibres was rough going at first — literally. Wild and early domesticated sheep have a bristly overcoat called the kemp and a fine undercoat of wool called the fleece. Over time, animals were selected for more fleece, with finer fibres, and less kemp. The more than 200 domesticated sheep breeds today are mostly kemp-free.
Modern wool fibres range from a fine 16 microns in diameter, from merinos, to 40 microns. [Ouessant wool is at the finer end of the spectrum, averaging around 25 microns]
That itch from your warm winter woolies? Most likely it’s sensitivity to thicker (and coarser) fibre diameter or fibre ends, not a wool allergy, which is practically unknown.
Less lush pastures — such as in a drought — can produce finer fibres, with smaller diameters.
Wool has been a valuable commodity across cultures and centuries. When Richard I (the Lionhearted) was captured in 1192, Cistercian monks paid their part of the ransom to the Holy Roman emperor in 50,000 sacks of wool (a year’s clip).
Wool has stood in for even more precious fabrics: In 18th-century Norway, when the king forbade the wearing of silk by commoners, farmers opted for imported worsted wool fabric, which had a similar sheen.Besides clothing, wool has quite a few industrial uses, from piano dampers for very small bits to large absorbent pads for those bad oil spills.
Wool has the right properties for ground covering in the garden because it’s a lightweight and allows seedlings to grow right through it. Ed. I am testing this out right now to see if airborne weeds can grow on top.
Wool is also biodegradable. It breaks down slowly, fertilising the plants with a generous nitrogen content of a whopping 17 percent compared with the 6 percent nitrogen in commercial turf products. And it is water-retentive.
In a seeming paradox, wool can absorb and repel water simultaneously.
The outer surface of wool fibre is made up of fatty acid proteins and does not absorb liquid. However, structural features in the fibres interior, called salt linkages, can sop up copious amounts of moisture in vapour form.
In short, wool hates liquid but loves vapour.
These qualities recently attracted the interest of the U.S. Army, which is researching wool’s potential in clothing designed to protect combat troops from explosive blasts.
With flame retardancy up tp 600c, Merino wool has long been the preferred material for firefighters uniforms. It doesn’t melt, shrink, or stick to skin when exposed to very high temperatures and has no toxic odours. Ed. not sure if this is used here.
We can thank wool for a different kind of explosion — one we actually want. Inside most baseballs, including those used in Major League Baseball, you’ll find layers of tightly wound wool yarn: Each ball contains about 370 yards of the wool windings, which provide resilience to withstand the crushing impact of a batter’s hit off high-velocity pitches.
Author: Marie Clarke (with acknowledgements to Discovery magazine)