My allusion was to the exclusion of Mr. Douglass from the common table of the mail-packet on the Potomac, almost within sight of the Executive Mansion, simply on account of color,--and I added, that the President, on whose invitation he had joined the Commission, never uttered a word in rebuke of this exclusion, and when entertaining the returned Commissioners at dinner carefully omitted Mr. Douglass, who was in Washington at the time, and thus repeated the indignity. On this you are represented as remarking, that General Sigel was also omitted, but that, in fact, Mr. Douglass and General Sigel had already left for their homes (forgetting that Mr. Douglass continued in Washington); and you do not allow yourself to doubt, that, had they been in town, they would have been included in the invitation. Your apology clearly shows your opinion that they ought to have been invited; but please not to forget that there was a reason for inviting Mr. Douglass that did not exist in the case of General Sigel. The General was white, and he had suffered no indignity on board a mail-packet which it was in the power of the President to rebuke by example. But you are mistaken in the facts, as appears by the newspapers of the time. The Commissioners reached Washington on the evening of March 27th. They were entertained at dinner by the President March 30th. On the day before the dinner Mr. Douglass presided at the Convention to nominate a Delegate to Congress from the District of Columbia, and on taking the chair made a speech. Mr. Chipman was nominated against Mr. Douglass, who made another speech thanking his supporters for their votes. To gratify the friends of Mr. Douglass, there was an understanding that he should succeed Mr. Chipman as Secretary of the District. These things show that Mr. Douglass was not only in Washington, but conspicuously so, presiding at a public Convention, and being voted for as a candidate for Congress.