COLONIALISM AND IMPERIALISM IN AFRICA
Both openly and by implication, all the European powers in the nineteenth century indicated their awareness of the fact that the activities connected with producing captives were inconsistent with other economic pursuits. That was the time when Britain in particular wanted Africans to collect palm produce and rubber and to grow a agricultural crops, for export in place of slaves; and it was clear that slave raiding was violently conflicting with that objective in Western, Eastern, and Central Africa.
The slave trade was abandoned because it no longer suited the capitalists' needs.

This was why Europe's relationship to Africa shifted from slave trading to colonialism. Kwame Nkrumah put it correctly: "Colonialism is, therefore, the policy by which the 'mother country,' the colonial power, binds her colonies to herself by political ties with the primary object of promoting her own economic advantages." He went on to point out:
Such a system depends on the opportunities offered by the natural resources of the colonies and the uses for them suggested by the dominant economic objectives of the colonial power. Under the influence of national aggressive self-consciousness and the belief that in trade and commerce one nation should gain at the expense of the other, and the further belief that exports must exceed imports in value, each colonial power pursues a policy of strict monopoly of colonial trade, and the building up of national power.
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The French Premier Jules Ferry, in a speech to the Chamber of Deputies in 1885, clearly articulated the main reasons Europe acquired its colonies: "The nations of Europe desire colonies for the following three purposes: (i) in order that they may have access to the raw materials of the colonies; (ii) in order to have markets for sale of the manufactured goods of the home country; and (iii) as a field for the investment of surplus capital." Many years later, Nkrumah, whose country underwent colonialism, spelled out the colonial policies the Europeans used to ensure their success in achieving these goals: "(i) to make the colonies non-manufacturing dependencies; (ii) to prevent the colonial subjects from acquiring the knowledge of modern means and- techniques for developing their own industries; (iii) to make colonial 'subjects' simple producers of raw materials through cheap labor; (iv) to prohibit the colonies from trading with other nations except through the 'mother country."'