35. Some of the spirits of the earth Mercury came to me, being sent by others, in order that they might hear what was going on near me. These were told by one of the spirits of our Earth, to tell their [friends] not to speak anything but what was true, and not, as they were wont, to present opposite things to their questioners; for that if any of the spirits of our Earth were to do so, he would be punished. But immediately the company from which those spirits had been sent forth, and which was at a distance, made answer, that if they must be punished on that account, they must all be punished, inasmuch as, from continual practice, they could not do otherwise. They said that when they speak with the men of their own earth, they also do likewise, not, however, with any intention to deceive, but to inspire the desire of knowing; for when they present opposite things, and conceal things in a certain manner, the desire of knowing is excited, and thus from the zeal of exploring those things, the memory is perfected. I also, on another occasion, spoke with them on the same subject, and, as I knew that they spoke with the men of their earth, I asked in what manner they instructed their inhabitants. They said that they do not instruct them fully as to how a matter is, but keep insinuating some apperception of it, in order that from this the desire of exploring and of acquiring knowledge may be nourished and grow; for if they were to answer all their questions, the desire would perish. They added, that they suggest opposites for this reason also, that the truth (_veritas_) may afterwards appear the better; for all truth appears from relation to its opposites. 36. It is their custom not to tell another what they know, but still they want to learn from all others what is known to them. With their own society, however, they communicate everything, insomuch that what one knows all know, and what all know each one in the society knows[l].