In their turn the English and the French, who had heard of the fabulous treasures of the Joliba valley and the Tinbukhtu mart, began to claim their share. As early as 1551 Captain Thomas Wyndham touched at the Gold Coast and brought home 150 lbs. of the precious dust. The first English company for exploring the Gambia River sent out (1618) their agent, Richard Thompson. This brave and unfortunate explorer was rancorously opposed by the Portuguese and eventually murdered by his own men. He was followed (1620) by Richard Jobson, to whom we owe the first account of the Gambia River. He landed at various points, armed with mercury, aqua regia (nitric acid), large crucibles, and a 'dowsing' or divining rod; [Footnote: A form of this old and almost universal magical instrument, worked by electricity, has, I am told, been lately invented and patented in the United States.] washed the sands and examined the rocks even beyond the Falls of Barraconda. After having often been deceived, as has occurred to many prospectors since his day, he determined that gold never occurs in low fertile wooded lands, but in naked and barren hills, which embed it in their reddish ferruginous soil. Hence it was long and erroneously determined that bare rocks in the neighbourhood of shallow alluvia characterise rich placers, and that the wealthiest mining-regions are poor and stunted in vegetation. California and Australia, the Gold Coast and South Africa, are instances of the contrary. Wasa, however, confirms the old opinion that the strata traversed by lodes determine the predominating metal; as quartz produces gold; hard blue slate, lead; limestone, green-stone and porphyry, copper; and granite, tin. [Footnote: Page 17, _A Treatise on Metalliferous Minerals and Mining_, by D. C. Davies. London, Crosby and Co., 1881. The volume is handy and useful to explorers.] After twenty days' labour Jobson succeeded in extracting 12 lbs. from a single site. He declares that at length he 'arrived at the mouth of the mine itself, and found gold in such abundance as surprised him with joy and admiration.' Unfortunately he leaves us no notice of its position; it is probably lost, like many of the old Brazilian diggings. The Gambia River still exports small quantities of dust supposed to have been washed in the Ghauts, or sea-subtending ridges, of the interior. Most of it, however, finds its way to the wealthier and more prosperous French colony. Whilst the English chose the Gambia the French preferred Senegal, where they founded (1626) 'St. Louis,' called after Louis XIV. The Sieur Brue, Director-General of the Senegal Company, made a second journey of discovery in 1698, and reached with great difficulty the gold-mines of desert and dreary Bambuk. There he visited the principal districts, and secured specimens of what he calls the _ghingan_, or golden earth. He proposed a third incursion, but the absolute apathy of his countrymen proved an insuperable obstacle.