*No. 69.[108]
Extract from Additional Instructions to Captain Prevost.
If, however, the commissioner of the United States will not adopt the line along Rosario Strait, and if, on a detailed and accurate survey, and on weighing the evidence on both sides of the question, you should be of opinion that the claims of Her Majesty’s government to consider Rosario Strait as the channel indicated by the words of the treaty cannot be substantiated, you would be at liberty to adopt any other intermediate channel which you may discover, on which the United States commissioner and yourself may agree as substantially in accordance with the description of the treaty.The British government in 1866 does not claim the so-called Rosario as the boundary.
Captain Prevost.