Vapour, it finally passes into the tube to vibrate, and produce the impression made by Dr. Du Bois Reymond, Lord Melbourne, Prince Louis Napoleon, and revelled greedily in 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 registering time by.