With the defeat of Napoleon at Waterloo in 1815, Britain was again pre-eminent among the great powers, and was to remain so for the next seventy years. Her colonial empire was far more extensive than that of any other country; London was the financial capital of the world; she had the largest navy and mercantile marine, the chief share of the world's trade, the highest manufacturing production, and the most progressive agriculture. From Castlereagh...