There was a folded bit of paper there, and Walter reached out for it, took it, and opened it up. It was covered on one side with some drawings and diagrams, and as Walter looked at them, not paying much attention at first, as he worked a high power formula over in his head, a little at a time it dawned on him as he continued to stare at Bauer's drawings, that without having realised it himself, perhaps, Bauer had actually suggested in his own drawing the key to the arc light Walter had been puzzling over for several months without success. "Yes! yes!" Walter was saying, excitedly, to himself. "I see it! I see it! What a dummy I was. The electrodes can be fitted with teeth at equal distances. Let the tooth rest on the porcelain plate. It will gradually soften and melt under the heat of the arc. Then--then. I see! I see--the electrode will, or it ought to, drop down of its own weight upon the next tooth. Then that will melt and the electrode will drop again. The two electrodes can be coupled together with a scissors coupling, so the teeth will have to be made in only one of them. I see the whole thing! Hurrah!" He said the last word out loud. The echo of it in the big, empty shop startled him. The glow of the discoverer, of the inventor, was on him and within him. Then he received a distinct reaction. That was Bauer's paper, not his! He had left it out of the locker when he went away! It was Bauer's discovery, not his, even if Bauer did not yet realise the real value and meaning of his diagram. He was on the road to the discovery. Walter stared at the paper again and wished he had never seen it. For he was face to face with a real temptation, one of the hardest and most alluring his young manhood had ever confronted, and he was afraid, as he continued to stare at the diagram made by Felix Bauer. CHAPTER IV IT was ten o'clock at night when Walter finally went out of the shop and up to his room. He did not turn on the light at once, but went over by his table and sat down. The temptation he still faced had assumed alluring shapes. In the first place, he was saying to himself, "Bauer's drawings differ only a trifle from my own and I had practically gone as far as he, only one or two points were suggested to me by his diagram of the electrodes resting at an angle on the porcelain plate. The cutting of the teeth in the soft metal was also suggested by him. But I had thought out other points that were essential."