Mechanical-advantage demonstration with pulley block and weight.
1932
Mechanical-advantage demonstration with windlass, pulley block and weight
1932
Mechanical-advantage demonstration with pulley block and weight.
1932
Pulley Block Made at the Block Mill, Portsmouth Dockyard, 1943-1953
1943-1953
Hexagonal fitting of black phenolic decorated with Gallia trademark
1931-1939
Triple pulley block
1752