The two known to me treating it at greatest length are (1) Callahan, _Diplomatic History of the Southern Confederacy_ and (2) Sears, _A Confederate Diplomat at the Court of Napoleon III_.Am.Hist.

Rev., Jan., 1921.

Both writers drew their information wholly from Confederate documents, using, especially, the private correspondence of Mason and Slidell, and neither treats the matter from the English view point.

I have therefore based my account on the unused letters of British officials, citing other materials only where they offer a side light.

The principal new sources are Cowley's private and official letters to Russell.] [Footnote 612: Russell Papers.