[68] The original South Sea Company, which became so notorious through its connection with the first great speculative mania in England in 1720, came into existence in 1711 (partly promoted, it may be, by Dampier and Daniel Defoe), for the purpose of trading with the "South Sea", viz. the Pacific Ocean, and chiefly the west coast of South America and the vaguely known islands of Oceania. It received in course of time certain concessions from Spain, such as the sole right to supply Negro slaves to the Pacific coast of Spanish America, and from the British Government the exclusive monopoly of British trade with the "South Seas". Although fraudulently speculative, it did not smash in 1720, but continued an uncertain existence till 1807. Amongst other privileges it received permission to coin the silver it brought back from Peru into shillings, and these were the "South Sea" shillings--coined mostly in 1723--so often referred to in the history of the eighteenth century. In 1762 he returned to England and married. His married life lasted for sixteen years, but it is computed that of that sixteen he spent only about four and a half in his wife's society, chiefly at a house in Shadwell, in the eastern part of London, which he bought for her. Nevertheless they were fond of one another, and a family of six children was born to them in course of time.[69] [69] All of whom died young, from illnesses or accidents. Mrs. Cook, the widow, lived to the age of ninety-three, and died in 1835. Between the time of his marriage and 1768 he began to make himself noteworthy by his publications of sailing directions and his work as a mathematician and astronomer; for he found the opportunity of observing a solar eclipse off the coast of North America, and described it very lucidly. Consequently, when at the instance of the Committee of the Royal Society, who were desirous that the transit of Venus across the disk of the sun should be carefully observed by competent persons from some central part of the Pacific Ocean, the British Admiralty decided to appoint James Cook to take charge of this expedition, and at the same time to make a determined search in the Central and Southern Pacific for the supposed vast southern continent, stretching from the south tropic to the South Pole. Cook, therefore, was given a commission as a lieutenant-commander, and appointed to H.M.S. _Endeavour_.[70] The _Endeavour_ was a sailing vessel of only 368 tons burden, which had been constructed at Whitby and purchased by the Admiralty. [70] Originally the Royal Society had suggested a Mr. Dalrymple, a sort of merchant-adventurer, who had traded a good deal in the Malay Archipelago, and who had formed and promulgated theories about the immense size of the Australian continent, but apparently Dalrymple knew very little about astronomy, and the Admiralty wisely refused to allow him to command the king's ship.