STEAM made ocean journeys very cheap, manufacturing wages provided small sums of capital, increased population provided a surplus for emigration, and after 1870 refrigeration made farming in remote colonies more profitable. There are now in the United States, the British Dominions, and South America more people of British descent than in the British Isles. The overseas dependencies belong to the British Empire largely as a consequence of British naval strength, and this strength during the past century was due to trade and the Industrial Revolution. It could not have been maintained by a poor country, however good its human material. The interest and value of these dependencies began to grow, and though they were encouraged to take responsible government as soon as possible in order to free the Mother Country of expense, it began to be expected that they would remain attached to her voluntarily. After 1880 the Imperial idea was cultivated and unwritten obligations were acknowledged by the Dominions during the wars of 1899-1902 and 1914-18. Economically, however, the Mother Country and the Dominions diverged.

The two original provinces of Canada were united in 1841 after much friction between old and new British settlers, and between the old-fashioned French Canadians and the British officials. Friction continued, but virtual self-government was conceded to Canada by the governor, Lord Elgin, acting in the spirit of the famous Report which Lord Durham had signed in 1839. In 1867 the Dominion of Canada was established, and soon included all the scattered Canadian colonies except backward Newfoundland. When railways were introduced, it became possible to administer Canada. Before the transcontinental lines were built there was no communication between East and West coasts except by sea round Cape Horn. The Dominion of Canada was a Federal Union, the provinces retaining great powers, like the American States, while the functions of the central Parliament were modelled on the British Constitution.