Note: Pages 457-98 identically in the 1902 editions contain "Appendix"/"Appendices" (US/UK), or Appendix A to Appendix E. • Appendix A to D, pp. 457-75 These feature secret writing, Francis Bacon's "Bi-Literal Cipher" and some derived ciphers. Presumably these support the role in the story of two encoded messages that are displayed on one unnumbered leaf following the Contents list. • Appendix E, pp. 476-98 "Narrative of Bernardino de Escoban, Knight of the Cross of the Holy See and Grandee of Spain" Several reviews mention the cipher. The earliest found (Louisville Courier-Journal 1902-03-29 p5) is the most emphatic, as it notes, "The clever[est?] ... of the book is the adaptation of the Baconian cipher in furthering the plot and the romance."

Synopsis: "When Archibald Hunter comes to Cruden Bay, Aberdeenshire, for his annual holiday, he looks forward to a tranquil few days by the sea. But as he sits by the bridge he is disturbed by a strange vision of a couple he had seen earlier, the man now carrying a small black coffin. Shortly afterwards he discovers their child has drowned. The following day, speaking to a fisherman, he is again confronted by a portent of doom. As he sets out to sea, the other men speak his name - Lauchlane Macleod: the very same whose death Gormala had foretold. But how can this gaunt old woman know such things? Where are these terrible visions, whose force he seems unable to counter, taking him? What is the significance of the pages of cipher which once belonged to Don de Escoban? Can he solve the Mystery of the Sea?" --quoted from this book's product page at Amazon UK as of 2017-08-29 --found 2019-05-10 as "From the Back Cover" at ASIN B079558GC5, 2018 Jovian Press ebook --Google Books 2019-05-10 quotes the same description for its display of the 1902 Doubleday, Page edition (as W. Heinemann, 1902) "What is the significance of the pages of cipher which once belonged to Don de Escoban? The cipher used is a Bacon biliteral cipher. Appendices to the novel contain an explanation of the Bacon biliteral cipher and of the solution process used. The main purpose of the novel seems to be not the plot, but the exposition of the cipher system and the solution of the cipher messages." --Original Crypto Fiction #120 (faculty.knox.edu/jdooley/Crypto/Crypto1.htm)