Having kept the middle watch, which is from twelve to four, Mr. Spokesly was sitting in his cabin abaft the bridge of the _Tanganyika_, his feet in a white-enamelled bucket of hot water, contemplating the opposite bulkhead. He was thinking very hard, according to the System of the London School of Mnemonics. The key of this system was simplicity itself. You wanted to remember something which you had forgotten. Very well; you worked back on the lines of a dog following a scent. From what you were thinking at the present moment to what you were thinking when you came in the door, which would lead you by gentle gradations back to the item of which you were in search. Very simple. Unfortunately, Mr. Spokesly, in the course of these retrograde pilgrimages, was apt to come upon vast and trackless oceans of oblivion, bottomless gulfs of time in which, as far as he could recall, his intellectual faculties had been in a state of suspended animation. The London School of Mnemonics did not seem to allow sufficiently for the bridging of these gaps. It is true they said in Lesson Three, with gentle irony, _Remember the chain of ideas is often faulty; there may be missing links_. Mr. Spokesly, who on this occasion was determined to remember what he was thinking of at the moment when the Old Man spoke sharply behind him and made him jump, was of the opinion that it was the chain that was often missing and that all he could discover were a few odd links! He lifted one foot out of the grateful warmth and felt the instep tenderly, breathing hard, with his tongue in one corner of his mouth, as his mind ran to and fro nosing at the closed doors of the past. What _was_ he thinking of? He remembered it attracted him strangely, had given him a feeling of pleasant anticipation as of a secret which he could unfold at his leisure. It was ... it was.... He put his foot into the water again and frowned. He had been thinking of Ada, he recalled----Ah! _Now_ he was on the track of it. He had been thinking not of her but of the melancholy fact communicated to him by his own sister, that Ada had no "dot," no money until her father died. Now how in the world did that come to react upon his mind as a pleasant thing? It was a monstrous thing, that he should have capsized his future by such precipitate folly! Mr. Spokesly comprehended that what he was looking for was not a memory but a mood. He had been in a certain mood as he stood on the bridge that morning about half-past three, his hand resting lightly on the rail, his eyes on the dim horizon, when the Old Man, in his irritating pink-striped pajamas, had spoken sharply and made him jump. And that mood, the product of some overnight reflections on the subject of will power, had been rising like some vast billow of cumulous vapour touched with roseate hues from a hidden sun, and he had been just on the brink of some surprising discovery, when----It was very annoying, for the Old Man had been preoccupied by a really very petty matter, after all. (The word "petty" was a favourite with Mr. Spokesly.) It had, however, broken the spell, and here he was, a few hours later, hopelessly snarled up in all sorts of interminable strings of ideas. The business of thinking was not so easy as the London School of Mnemonics made out. Lifting his feet slowly up and down, he reached out and took Lesson Number Five from the holdall (with his initials in blue) which hung above his head. As he turned the richly printed pages, a delicious feeling of being cared for and caressed stole over him. _Never despair_, said the Lesson gravely, _Nil Desperandum. Just as the darkest hour is before the dawn, so victory may crown your toil at the least likely moment._