“It reached me,” continued Thorndyke, “only after Dr. Jervis had started for Densford. The greater part of one side was blank, excepting for a rough plan drawn in pencil, and this blank side I laid down on a sheet of glass and wetted the written side with a small wad of cotton-wool dipped in distilled water. Of course, the blue writing began to run and dissolve out; and then, very faintly, some other writing began to show through in reverse. I turned the paper over, and now the new writing, though faint, was quite legible, and became more so when I wiped the blue-stained cotton-wool over it a few times. A solution of methylene blue would have made it still plainer, but I used water only, as I judged that the blue writing was intended to furnish the dye for development. Here is the final result.” He drew from his pocket a letter-case, from which he extracted a folded paper which he opened and laid on the table. It was stained a faint blue, through which the original writing could be seen, dim and blurred, while the secret message, though very pale, was quite sharp and clear. And this was the message: “… so although we are not actually blown on, the position is getting risky and it’s time for us to hop. I have booked passages for the four of us to Ostend by the _Cornflower_, which sails on Friday evening next (20th). The names of the four illustrious passengers are, Walsh (that’s me), Grubb (Dorman), Jenkins (Spiller), and Thorpe (that’s you). Get those names well into your canister--better make a note of them--and turn up in good time on Friday.” “Well,” said Miller, as he handed back the letter, “we can’t know everything--unless we are Dr. Thorndyke. But there’s one thing I do know.” “What is that?” I asked. “I know why that fellow, Pinder, grinned when I told him that I had photographed his confounded letters.” IV. THE NATURALIST AT LAW A hush had fallen on the court as the coroner concluded his brief introductory statement and the first witness took up his position by the long table. The usual preliminary questions elicited that Simon Moffet, the witness aforesaid, was fifty-eight years of age, that he followed the calling of a shepherd and that he was engaged in supervising the flocks that fed upon the low-lying meadows adjoining the little town of Bantree in Buckinghamshire. “Tell us how you came to discover the body,” said the coroner.