"That is frozen dynamite," continued the Professor, "and is, as I have said, practically harmless. Now, it will be my pleasure to perform two startling experiments with the unfrozen substance," and with that he picked up a handful of the wet sawdust and flung it on a small iron anvil that stood on the table. "You will enjoy these experiments," he said, "because it will show you with what ease dynamite may be handled. It is a popular error that concussion will cause dynamite to explode. There is enough dynamite here to blow up this hall and to send into oblivion every person in it, yet you will see whether or not concussion will explode it." The Professor seized a hammer and struck the substance on the anvil two or three sharp blows, while those in front of him scrambled wildly back over their comrades, with hair standing on end. The Professor ceased his pounding and gazed reproachfully at them; then something on the anvil appeared to catch his eye. He bent over it and looked critically on the surface of the iron. Drawing himself up to his full height again, he said, "I was about to reproach you for what might have appeared to any other man as evidence of fear, but I see my mistake. I came very near making a disastrous error. I have myself suffered from time to time from similar errors. I notice upon the anvil a small spot of grease; if my hammer had happened to strike that spot you would all now be writhing in your death-agonies under the ruins of this building. Nevertheless, the lesson is not without its value. That spot of grease is free nitro- glycerine that has oozed out from the dynamite. Therein rests, perhaps, the only danger in handling dynamite. As I have shown you, you can smash up dynamite on an anvil without danger, but if a hammer happened to strike a spot of free nitroglycerine it would explode in a moment. I beg to apologize to you for my momentary neglect." A man rose up in the middle of the hall, and it was some little time before he could command voice enough to speak, for he was shaking as if from palsy. At last he said, after he had moistened his lips several times:-- "Professor, we are quite willing to take your word about the explosive. I think I speak for all my comrades here. We have no doubt at all about your learning, and would much prefer to hear from your own lips what you have to say on the subject, and not have you waste any more valuable time with experiments. I have not consulted with my comrades before speaking, but I think I voice the sense of the meeting." Cries of "You do, you do," came from all parts of the hall. The Professor once more beamed upon them benevolently.