The boundary from the St. Lawrence westward through the Great Lakes and thence to the Lake of the Woods had been laid down in the Treaty of 1783 in the usual vague terms, but it was determined in a series of negotiations from 1794 to 1842 with less friction and heat than the eastern line had caused. From the Lake of the Woods to the Rockies a new line, the forty-ninth parallel, was agreed upon in 1818. Then, as the Pacific Ocean was neared, the difficulties once more increased. There were no treaties between the two countries to limit claims beyond the Rockies. Discovery and settlement, and the rights inherited from or admitted by the Spaniards to the south and by the Russians to the north, were the grounds put forward. British and Canadian fur traders had been the pioneers in overland discovery, but early in the forties thousands of American settlers poured into the Columbia Valley and strengthened the practical case for their country. "Fifty-four forty or fight"--in other words, the calm proposal to claim the whole coast between Mexico and Alaska--became the popular cry in the United States; but in face of the firm attitude of Great Britain and impending hostilities with Mexico, more moderate counsels ruled. Great Britain held out for the Columbia River as the dividing line, and the United States for the forty-ninth parallel throughout. Finally, in 1846, the latter contention was accepted, with a modification to leave Vancouver Island wholly British territory. A postscript to this settlement was added in 1872, when the German Emperor as arbitrator approved the American claim to the island of San Juan in the channel between Vancouver Island and the mainland.* * See "The Path of Empire". With the most troublesome boundary questions out of the way, it became possible to discuss calmly closer trade relations between the Provinces and the United States. The movement for reciprocal lowering of the tariffs which hampered trade made rapid headway in the Provinces in the late forties and early fifties. British North America was passing out of the pioneer, self-sufficient stage, and now had a surplus to export as well as townbred needs to be supplied by imports. The spread of settlement and the building of canals and railways brought closer contact with the people to the south. The loss of special privileges in the English market made the United States market more desired. In official circles reciprocity was sought as a homeopathic cure for the desire for annexation. William Hamilton Merritt, a Niagara border business man and the most persistent advocate of closer trade relations, met little difficulty in securing almost unanimous backing in Canada, while the Maritime Provinces lent their support.