Commerce is in most cases the mainspring of the relationship between colonies and the governing country. Say what we may of benevolent assimilation and the government of colonies for the good of the governed, there can be no doubt that commerce has been and is the underlying motive in the acquisition and continued control of a large proportion of the world's area now known as colonies, dependencies, or protectorates. In a few cases, like our own Philippine Islands, the control of territory has been assumed as a necessary result of war waged for purposes other than territorial acquisition; but the expectation of commercial advantages, present or prospective, may be properly assigned as a leading cause for the control which a half-dozen temperate-zone nations now exercise over 25 million square miles of non-contiguous territory occupied by 500 million people, a territory lying largely within the Tropics and a people largely of habits different from those of the governing country.