"Not at all, Geoffrey. A mystery is like a conjuring trick—seemingly insoluble, but you know how it is done, and then it becomes bald and commonplace. Suppose the stuff is mixed with water and the mixture placed in a small spray worked by an india-rubber ball. Then one goes into the dining hall for half a minute, gives two or three rapid motions of the hand, and the thing is accomplished."
"Yes, that sounds easy. You speak as if you knew who did it."
"Yes," Ralph said, with one of his spasmodic smiles, "I do."
"You know the author of this dastardly thing. Tell me."
"Not yet. I dare not tell you, because you are young and might betray yourself. I could not confide my secret to any one, even the best detective in England. It is only known to Tchigorsky and myself. You shall help me in drawing the net around the miscreants, but you must not ask me that."
"And to-night's doings are to remain a secret?"
"Of course. Nobody is to know anything. They may conjecture as much as they like. Good heavens, if any one in the house were to know what I have told you to-night, all my work would be undone. You are my instrument, by which I ward off danger without attracting attention to myself. You are the unsuspecting boy, who by sheer good luck foils the enemy. Keep it up, keep it up; for so long as you appear young and unsophisticated, there is less of the deadly danger."