The Tibbetts-Jelf Lamp was something new in motor lamps. It was a lamp which had all the advantages of the old lamp, plus properties which no lamp had ever had before, and it had none of the disadvantages of any lamp previously introduced, and, in fact, had no disadvantages whatsoever. So Jelf told Bones with great earnestness.
"You know me, Tibbetts," he said. "I never speak about myself, and I'm rather inclined to disparage my own point of view than otherwise."
"I've never noticed that," said Bones.
"You know, anyway," urged Jelf, "that I want to see the bad side of anything I take up."
He explained how he had sat up night after night, endeavouring to discover some drawback to the Tibbetts-Jelf Lamp, and how he had rolled into bed at five in the morning, exhausted by the effort.
"If I could only find one flaw!" he said. "But the ingenious beggar who invented it has not left a single bad point."
He went on to describe the lamp. With the aid of a lead pencil and a piece of Bones's priceless notepaper he sketched the front elevation and discoursed upon rays, especially upon ultra-violet rays.
Apparently this is a disreputable branch of the Ray family. If you could only get an ultra-violet ray as he was sneaking out of the lamp, and hit him violently on the back of the head, you were rendering a service to science and humanity.
This lamp was so fixed that the moment Mr. Ultra V. Ray reached the threshold of freedom he was tripped up, pounced upon, and beaten until he (naturally enough) changed colour!
It was all done by the lens.