In America France regained Louisiana, covering the mouth of the Mississippi. It had been in Spanish hands since 1763; but Talleyrand, Bonaparte's foreign minister, put pressure upon Spain, and Louisiana became French once more under the secret treaty of San Ildefonso (October 1800). The news of the retrocession, however, aroused intense feeling in the United States, inasmuch as the establishment of a strong foreign power at the mouth of the principal water-way in the country jeopardised the whole trade of the Mississippi valley. President Jefferson, recognising that the perpetuation of the new situation "would have put us at war with France immediately," sent James Monroe to Paris to negotiate. As Bonaparte plainly saw at the beginning of 1803 that another war with Great Britain was inevitable, he did not wish to embroil himself with the Americans also, and agreed to sell the possession to the Republic for eighty million francs. Indeed, he completed arrangements for the sale even before Monroe arrived. Some efforts had also been made, at Bonaparte's instance, to induce Spain to give up the Floridas, East and West, but European complications prevented the exertion of pressure in this direction; and the whole of Florida became part of the United States by treaty signed in 1819. The sale of Louisiana lowered the French flag on the only remaining portion of American territory that acknowledged the tricolour, except the pestilential fragment of French Guiana, on the north-east of South America, where France has had a footing since the beginning of the seventeenth century, save for a short interval (1809 to 1815) when it was taken by the British and Portuguese. But the possession has never been a profitable one, and a contemporary writer, quoting an official publication, describes it as enjoying "neither agriculture, commerce, nor industry."* (* Fallot, L'Avenir Colonial de la France (1903) page 237.) In the West Indies, France had lost Martinique and Guadeloupe during the naval wars prior to Bonaparte's ascension to supreme authority. These islands were restored to her under the Treaty of Amiens; were once more captured by the British in 1809 to 1810; and were finally handed back to France under the Treaty of Paris in 1814. Tobago and St. Lucia, taken from France in 1803, were not restored.