Correspondence with clockmakers and other papers concerning new clocks and improvements. There are papers on the Royal Exchange and Hamburg clocks; the rating of the Royal Exchange Clock for 1848; ratings of various chronometers; elasticity of balance springs; improved and new escapements; E.J. Dent's magneto-electric dial; and improved pendulums by J.G. Ulrich and E.T. Loseby. The correspondents include H.C. Schumacher, Lord Wrottesley, F. Beaufort and R. Sheepshanks.