With the advent of the Industrial Revolution, the traditional triangular trade of sugar, tobacco and slaves was no longer relevant. Demand for industrial raw materials, such as cotton, wool, fuel, iron, copper, tin, coal, etc. in the industrial countries replaced demand for consumer goods, and there was an urgent need for these countries to develop markets outside their own countries to absorb the manufactured goods produced in their own countries. As the European market was saturated, it had to look to the Americas and Asia (which had not yet colonized Africa) for growth.
After the independence of thirteen states in North America in 1776, Britain’s colonial cause suffered a great blow, so it shifted its colonial policy focus from North America to India, which had more abundant resources and a larger market. Britain also occupied Australia, New Zealand, Burma, the Cape Colony, and Hong Kong in China.
Due to the influence of the innate human rights concept advocated by the French Revolution and religious, humanitarian and economic reasons, Britain outlawed slave trade in 1807. Later, the Netherlands, France, Sweden, Denmark and other countries also outlawed slave trade. As a result of this measure, the strongholds of all countries on the coast of Africa shrank rapidly. Denmark and the Netherlands both sold their commercial stations on the coast of West Africa in the mid-19th century. At the same time, due to the impact of the Napoleonic Wars, the Spanish and Portuguese colonies in the Americas declared independence one after another, the demand for slaves decreased sharply, and the colonial power of these two countries in Africa also weakened rapidly.
In North Africa, France took advantage of the decline of Turkey and infiltrated Algeria, Morocco, Tunisia and other Turkish vassal states with the opportunity of eliminating pirates in North Africa. Algeria, where pirates were most active, was hit the hardest. In 1815, the Algerian Navy was defeated by the American Navy, and in 1819, the Anglo-Dutch fleet bombarded the city of Algiers. France also had several conflicts with Algeria, which it occupied in 1830.
From 1825 to 1875, the conquest of new colonies by European countries, with the exception of Britain and France, had largely ceased, replaced by emigration to overseas colonies. In the case of Britain, British Prime Minister Disraeli said in 1852 that the British attitude towards colonies during this period can be best summed up: “Colonies are a millstone hanging around our necks.” In the case of the two small British colonies in the Gambia and on the Gold Coast, commercial taxes were not enough to keep up with administrative costs. The British Parliament suggested several times that the colonies should be reduced in size or abandoned altogether, only to retain them because the West African Branch of the Royal Navy needed a naval base in the Gulf of Guinea to ban the slave trade.
However, in order to house freed black slaves in the Caribbean islands, the British created colonies in Sierra Leone during the period of colonial atrocity by establishing licensing companies, the American Colonial Society established colonies in Liberia at the same time, and the French established colonies in Libreville (modern Gabon), which were used to house freed slaves.