The reply of Mr. McLane to the preceding note is dated on the 11th of March. He expressed his regret that His Britannic Majesty's Government should still consider any part of the opinion of the arbiter obligatory on either party. Those opinions, the Secretary stated, could not have been carried into effect by the President without the concurrence of the Senate, who, regarding them not only as not determining the principal object of the reference, but as in fact deciding that object to be impracticable, and therefore recommending to the two parties a boundary not even contemplated either by the treaty or by the reference nor within the power of the General Government to take, declined to give their advice and consent to the execution of the measures recommended by the arbiter, but did advise the Executive to open a new negotiation for the ascertainment of the boundary in pursuance of the treaty of 1783, and the proposition of Mr. Livingston, submitted in his letter of 30th of April, 1833, accordingly proceeded upon that basis. Mr. McLane denied that a decision, much less the expression of an opinion, by the arbiter upon some of the disputed points, but of a character not to settle the real controversy, was binding upon either party, and he alleged that the most material point in the line of the true boundary, both as it respects the difficulty of the subject and the extent of territory and dominions of the respective Governments, the arbiter not only failed to decide, but acknowledged his inability to decide, thereby imposing upon both Governments the unavoidable necessity of resorting to further negotiation to ascertain the treaty boundary and absolving each party from any obligation to adopt his recommendations. The Secretary also declined to admit that of the three main points referred to the arbiter as necessary to ascertain the boundary of the treaty he had decided two. On the first point, Mr. McLane said, it was not contended a decision was made or that either the angle or the highlands called for by the treaty was found, and on the third point an opinion merely was expressed that it would be suitable to proceed to fresh operations to measure the observed latitude, etc.