Proofs of "Mars" (Is Mars Habitable?), all William's suggestions adopted, Lowell quoted on atmosphere of Mars; Lowell doing a series of popular articles in Century magazine so a "fair stand-up fight" between him and ARW; will now continue with work on "Spruce", (Notes of a Botanist on the Amazon and Andes by Richard Spruce, ed. and condensed by ARW, Dec. 1908) intends to include matter from Spruce articles and reports for Linnean Society, Geographical Society and Blue books and some new letters, cutting out much of the Journal and botanical matter to make the book more readable; supposes they must wait 6 months for the "Widows" [Scottish Widows insurance].