Piece of steel showing a friction stir weld join, 2000.

Piece of steel showing a friction stir weld join, 2000.

Stir weld update, Challenge of Materials Gallery, Science Museum, Nov 2000.

Stir weld update, Challenge of Materials Gallery, Science Museum, Nov 2000.

Charles Augustin de Coulomb, French physicist, c 1780.

Cylinder escapement stopwatch, 1748.

Records from Coulomb's memoir, c 1884.

Screwdrivers and other tools, 1996.

Bridge of Tsin-kiang-fou, China, late 18th century.

Bridge of Cou-tcheou-fou, China, late 18th century.

Bridge of Fou-yang-hien, China, late 18th century.

Bow drill, Egypt, c 1480 BC.