unquestionable

In an incoherent and, as I deeply feel, an entirely inadequate fashion, I have endeavoured to give some account of my strange experiences in his company from the chance which first brought us together at the period of the “Study in Scarlet,” up to the time of his interference in the matter of the “Naval Treaty”—an interference which had the unquestionable effect of preventing a serious international complication.

“Well, then, under these circumstances,” said Caderousse, “I will, I even believe I ought to undeceive you as to the friendship which poor Edmond thought so sincere and unquestionable.”