Query: When did the Island start to experience a period of prosperity?
Context: 18th century governors tried to tackle the island's problems by implementing tree plantation, improving fortifications, eliminating corruption, building a hospital, tackling the neglect of crops and livestock, controlling the consumption of alcohol and introducing legal reforms. From about 1770, the island enjoyed a lengthy period of prosperity. Captain James Cook visited the island in 1775 on the final leg of his second circumnavigation of the world.