Barley and Yak

Barley ripens higher than any other cereal, and the altitude at which it stops is the altitude at which settled farming stops.

Roasted barley flour keeps, needs no cooking and can be eaten anywhere, which is why it is the staple rather than bread.

Transport, wool, milk, hair for tents and dung for fuel in a place with no wood — the whole economy rests on one animal.

Woven from yak hair, the cloth swells when wet and closes its own weave, so a loose fabric becomes a rainproof roof.

Salt from the northern lakes moved south and grain moved back, on the backs of the same animals.