"Have no fear, I will not explode it. Now watch me closely. I will ignite a minute quantity, about as much as would make the head of a small black pin or a No. 4 bird-shot. See, the rest we will put in this pail of water. There--now all is ready--here goes!" He lit a match and touched the little brown dot--a tremendous explosion followed and the wooden table was split into pieces. The sound was so terrific and the shock so unexpected that I was dizzy and frightened. "Great heavens!" I exclaimed, "you have broken everything in the laboratory!" "No," replied the ghost rather shamefacedly, "not so bad as that, but I'm afraid that I have ruined the table and cracked a few things; however, I will be more careful next time: it is even more powerful than I thought. What do you suppose would be the effect on a warship if struck with a shell containing one hundred pounds of that stuff?" I answered that she would be destroyed. "Destroyed? I should say she would; the largest battleship would be blown to atoms." The spook glanced at an old-fashioned Dutch clock in the corner of the laboratory. "Fine clock that; glad I didn't break it with our little racket just now. I see I have nearly an hour to spare. Is there any experiment you would like to try?" I said anything would interest me, but that I didn't care for any more explosives. "I suppose you know how to make diamonds, don't you?" I answered that for years men had tried to manufacture diamonds, but practically without success; that as far as I was aware they had only succeeded in making them so small as to be practically of no use commercially, and the expense of the manufacture was far in excess of their value. "That's all right," answered the spook; "but really it is a very simple matter. Here; I will make a diamond for you." He walked across the room to the fireplace, and taking from the grate a lump of coal about the size of a billiard ball, he laid it upon the table. "This," he said, "is nearly pure carbon, and as you are well aware it is practically what a diamond is. Now, I will illustrate to you how you may make a diamond from this piece of coal, which will be as good as any diamond ever found in the mines. We will manufacture it instead of letting nature do it. "We will first place it in this glass bowl, and pour over it sufficient liquid air to cover it completely. We will let it remain until it is thoroughly cold, say, at least 200° below zero; there--now all we have to do is to heat it and then subject it to a powerful--Great Gee Hosiphat! Five minutes to twelve! I must go--appointment with a lady at twelve. But I say, old fellow, just hold it under the blowpipe and get it hot--just as hot as you can; I will be back soon--ta-ta." His last words came to me faintly through the window--he had already floated out.