I knew that I should have given the direct quote, its different than my memory.

entry for "February 8, 1861...After dinner, in the general conversation, some one venturing to ask Governor Seward how he could utter officially what the Virginians regarded as such truculent language in regard to the way in which New York should treat Southern reclamations for runaway slaves, Governor Seward threw himself back in his chair, burst ont laughing violently, and said: “Is it possible you gentlemen suppose I believe any such — nonsense
as that’? It’s all very well, and in fact it’s necessary, to be said officially up there in New York for the benefit of the voters, but surely we ought to be able to understand each other better over a dinnertable!”

This meeting must have been in the 1840s when Seward was a Governor because it does not give the date. Just the date of when the writer heard this from Mr. Seddon who witnessed the conversation.

David