His usual and lesser crime was to do all the arithmetic for the bunch and so gain time for sport. He had been punished in school and out of school for this misdemeanor, but he would never promise not to repeat it. What could a teacher say to a beautiful boy who smiled into her eyes and declared it “anti-social” not to help the other kids! Marvin led everything and apparently had no desire to lead anything. He led because his brain was a little quicker, his foot a little swifter, his eye a little surer than those of any mate. He was the undisputed cockerel of the walk. As for girls—only God knew what he might be guilty of in the course of the next ten years. Chase lamented that his own energy seemed so little tempered in Marvin by the mother’s steadiness. It was only in fits of abstraction that Marvin looked like the Helen Marvin whom Chase had loved these five and twenty years. The boy had some of the makings of a scientific genius—the quickness and accuracy of observation, the mathematical power, the swift intuition—but he seemed to lack the power of quiescence which permits a real genius to brood doggedly on a single problem. Presently Marvin bounded up the steps, balancing the glass jar, with some water in it, on the back of his left hand. Chase explained that the process of separating water into two gases is electrical, and that the simplest way to get a current is to bring zinc and sulphuric acid together in the water. He said that both materials could be found in the room, and having said it returned to his writing. There stood Marvin, left to his own devices, permitted to blow his eyes out if he so desired. He rolled up a strip of zinc, dropped it into the water, and corked the jar. Then he punched a hole and inserted a small glass funnel to let the sulphuric in. It stood to reason that there should be another hole and a pipe to let the hydrogen out. He punched a second hole and inserted a piece of glass tubing. So far, so good. It was the first time he had been allowed to monkey with the wonderful things in that corner of the den. He took down the bottle of sulphuric and pondered. If anything went wrong, dad would never let him try it again. If the acid made the water bubble and the hydrogen come out of the tube, would it be safe to light it like a gas jet? No, because there was no pressure and the flame would backfire into the jar. He removed the tube and bent it in the flame of a bunsen burner. He thrust the short end back through the cork and ducked the other end into a bowl of water. Then he poured in a little acid and watched. Sure enough, bubbles began to rise and the glass grew warm, even hot Presently corresponding bubbles appeared on the surface of the bowl. He stirred in a little soap so that he could see them better, and they collected in iridescent masses.