certain number of questions and put them in sealed envelopes. Then, on entering the presence of the horse, they would take one of the envelopes at random, open it and write down the problem on the black-board; and Mohammed or Zarif would answer with the same facility and the same readiness as though the solution had been known to all the onlookers. But was it really unknown to their subconsciousness? Who could say for certain? Tests of this kind require extraordinary precautions and a special dexterity; for the action of the subconsciousness is so subtle, takes such unexpected turns, delves in the museum of so many forgotten treasures and operates at such distances that one is never sure of escaping it. Were those precautions taken? I was not convinced that they were; and, without pretending to decide the question, I said to myself that my blissful ignorance of mathematics might perhaps be of service in shedding light upon some part of it. For this ignorance, however deplorable from other points of view, gave me a rare advantage in this case. It was in fact extremely unlikely that my subliminal consciousness, which had never known what a cubic root was or the root of any other power, could help the horse. I therefore took from a table a list containing several problems, all different and all equally unpleasant looking, covered up the solutions, asked Krall to leave the stable and, when alone with Zarif, copied out one of them on the black-board. In order not to overload these pages with details which would only be a repetition of one another, I will at once say that none of the antitelepathic tests succeeded that day. It was the end of the lesson and late in the afternoon; the horses were tired and irritable; and, whether Krall was there or not, whether the problem was elementary or difficult, they gave only absurd replies, wilfully "putting their foot in it," as one might say with very good reason. But, next morning, on resuming their task, when I proceeded as described above, Mohammed and Zarif, doubtless in a better temper and already more accustomed to their new examiner, gave in rapid succession correct answers to nearly every problem set them. I am bound in fairness to say that there was no appreciable difference between these results and those which are obtained in the presence of Krall or other onlookers who, consciously or unconsciously, are already aware of the answer required.