Having ejected the poor discomfited animal, who was making her way towards him to be congratulated, as usual, upon her prowess, Claude turns to pick up the fallen books.
He has replaced all but two, when he stops short, for the feel of the smooth, cold cover of one of them now in his hand has made him thoughtful again. Strange what a host of memories will crystallize into shape, one after another, in the brain, like the scintillating colours of the kaleidoscopes,—all arising from a simple keynote set buzzing by some slight passing circumstance. The book he held in his hand was a rough copy-book, so dilapidated that he had hesitated to pack it in his boxes when coming to the colony. In it, when a boy at school, he used to keep his notes upon the science lectures delivered once a fortnight to the assembled scholars. He remembered, in the semi-darkness, how fond he was of those lectures. He recollected, as if it had occurred but yesterday, that he was holding the book just in that position when, at the end of one lecture, he rose in exceeding trepidation to ask a question relative to biblical science that caused an awful hush to fall upon the schoolroom. There before his mind’s eye was the picture of the professor—who was small, and rather nervous amongst boys—as he blushed, stammered, and finally refused to answer “a foolish question,” to the delight of the boys, his pupils, and the glorification of Claude in the playground by-and-by.
Claude turns up the light, and glances through the pages covered with his long-past schoolboy scrawl. His whole attention is however presently directed to a note on a scribbled memorandum, which relates, as a fact, that iodine can be employed to determine whether certain infusoria, in water taken from a pond or ditch, belong to the animal or vegetable kingdom. “The former,” says the note, “do not contain starch and remain unaltered in colour; the latter turn blue upon coming in contact with the iodine.”
Just as the thoughts, roused by reading these words, are shaping themselves for action in Claude’s brain, a step is heard on the stairs, the handle of the door rattles, and Dick enters the room. He is in his pyjamahs, just as he has tumbled out of his bed.
“I guessed you’d be grinding away at your letter,” he roars, “so having had a bright idea I thought I would come and lend you a hand. Cryptography’s the answer to the doctor’s puzzle, and your iodine will do something towards bringing the secret to light.”
“Well, we’ll try, without wasting further time,” and Claude, going out of the room, presently returns with a wine-glass half full of light-brown liquor.
“It’s mighty strange that you should have hit on what I believe is the answer to the puzzle just as I had done the same thing.” Here the speaker pushes the manuscript book towards Dick, who, sitting on the table, is cutting some tobacco for his pipe off a rough roll of Maori-prepared leaf, called torori.
Claude now pours some of the liquid, which contains about forty per cent. of iodine, into a plate, and proceeds with some hesitation to moisten a corner of the letter with the same. Both young men watch the result breathlessly. There is no result. Claude’s face clouds over with a disappointed look; but he nevertheless plunges half the sheet beneath the surface of the liquor.
As if by magic a change immediately begins to make itself apparent upon the surface of the paper.
At right angles to the pencil writing there gradually appears, after the manner of a photographic negative that is being developed, a series of parallel lines of disjointed dots and dashes, of a faint blue colour. These markings grow stronger each minute. The letter is wholly immersed, and presently withdrawn and held to the lamp. A hitherto hidden message, written in fairly distinct blue-green characters, is now visible. It runs as follows:—