“The first part is to take hold of the knobs,” putting them into Bruno’s hands. “The second part is——” Here he turned the handle, and, with a loud “Oh!”, Bruno dropped both the knobs, and began rubbing his elbows. The Professor chuckled in delight. “It had a sensible effect. _Hadn’t_ it?” he enquired. “No, it hadn’t a _sensible_ effect!” Bruno said indignantly. “It were very silly indeed. It jingled my elbows, and it banged my back, and it crinkled my hair, and it buzzed among my bones!” “I’m sure it _didn’t_!” said Sylvie. “You’re only inventing!” “Oo doosn’t know nuffin about it!” Bruno replied. “Oo wasn’t there to see. Nobody ca’n’t go among my bones. There isn’t room!” “Our Second Experiment,” the Professor announced, as Bruno returned to his place, still thoughtfully rubbing his elbows, “is the production of that seldom-seen-but-greatly-to-be-admired phenomenon, Black Light! You have seen White Light, Red Light, Green Light, and so on: but never, till this wonderful day, have any eyes but mine seen _Black Light_! This box,” carefully lifting it upon the table, and covering it with a heap of blankets, “is quite full of it. The way I made it was this—I took a lighted candle into a dark cupboard and shut the door. Of course the cupboard was then full of _Yellow_ Light. Then I took a bottle of Black ink, and poured it over the candle: and, to my delight, every atom of the Yellow Light turned _Black_! That was indeed the proudest moment of my life! Then I filled a box with it. And now—would any one like to get under the blankets and see it?” Dead silence followed this appeal: but at last Bruno said “_I’ll_ get under, if it won’t jingle my elbows.” Satisfied on this point, Bruno crawled under the blankets, and, after a minute or two, crawled out again, very hot and dusty, and with his hair in the wildest confusion. “What did you see in the box?” Sylvie eagerly enquired. “I saw _nuffin_!” Bruno sadly replied. “It were too dark!” “He has described the appearance of the thing exactly!” the Professor exclaimed with enthusiasm. “Black Light, and Nothing, look so extremely alike, at first sight, that I don’t wonder he failed to distinguish them! We will now proceed to the Third Experiment.” The Professor came down, and led the way to where a post had been driven firmly into the ground. To one side of the post was fastened a chain, with an iron weight hooked on to the end of it, and from the other side projected a piece of whalebone, with a ring at the end of it. “This is a _most_ interesting Experiment!” the Professor announced. “It will need _time_, I’m afraid: but that is a trifling disadvantage. Now observe. If I were to unhook this weight, and let go, it would fall to the ground. You do not deny _that_?” Nobody denied it. “And in the same way, if I were to bend this piece of whalebone round the post—thus—and put the ring over this hook—thus—it stays bent: but, if I unhook it, it straightens itself again. You do not deny _that_?”