VITALITY. THE origin, growth, and the children of a bridge. This went on to the construction of timepieces--The driving power--The escapement--Compensating pendulums--The spring balance--The cylinder escapement--The lever escapement--Compensated balance-wheels--Keyless winding mechanism for watches--The hour hand train. LOCKS:--The Chubb lock--The Yale lock. THE CYCLE:--The gearing of a 'materialism.