Four days later his judgment was improved, for he began, and thereafter maintained with vigour, the "high moral purpose" argument as evinced in the emancipation proclamation.
"The interests of humanity," he wrote to Adams, "have now become identified with the cause of our country[918]...." That the material interests of Great Britain were still in Seward's thought is shown by the celerity with which under Lincoln's orders he grasped at an unexpected opening in relation to liberated slaves.

Stuart wrote in mid-September that Mr.Walker, secretary of the colony of British Guiana, was coming from Demerara to Washington to secure additional labour for the British colony by offering to carry away ex-slaves[919].

This scheme was no secret and five days after the issue of the proclamation Seward proposed to Stuart a convention by which the British Government would be permitted to transport to the West Indies, or to any of its colonies, the negroes about to be emancipated.

On September 30, Adams was instructed to take up the matter at London[920].
Russell was at first disinclined to consider such a convention and discussion dragged until the spring of 1864, when it was again proposed, this time by Russell, but now declined by Seward.

In its immediate influence in the fall of 1862, Seward's offer had no effect on the attitude of the British Government[921].
To Englishmen and Americans alike it has been in later years a matter for astonishment that the emancipation proclamation did not at once convince Great Britain of the high purposes of the North.