"Well, I'm off," said Pierce cheerfully; "got to visit the other dumps."

"Stop a minute," said Blair, as the other turned away. "Haven't you any sort of public news as well as private news? How are things going in the political world?"

"Expressed in mathematical formula," replied Pierce over his shoulder, "the political news is MP squared plus LSD over U equals L. L let loose. L upon earth, my boy."

And he climbed again into his castle of the air.

Oliver Green stood staring at the crumbled paper and suddenly began to straighten it out.

"Mr. Blair," he said, "I am terribly ashamed of myself. When I see you living here like a hermit in the mountains and scrawling your calculations, so to speak, on the rocks of the wilderness, devoted to your great abstract idea, vowed to a great cause, it makes me feel very small to have entangled you and your friends in my small affairs. Of course, the affair isn't at all small to me; but it must seem very small to you."

"I don't know very precisely," answered Blair, "what was the nature of the affair. But that is emphatically your affair. For the rest, I assure you we're delighted to have you, apart