"How came people to find these things out?"
"By watching—and experimenting—and calculating."
"Then how big is the sun, Dr. Sandford?"
"How big does it look?"
"Not very large—I don't know—I can't think of anything it looks like."
"It looks just about as big as the moon does."
"Is it just the same size as the moon? But Dr. Sandford, it is a great deal further off, isn't it?"
"Four hundred times as far."
"Then it must be four hundred times as large, I should think."
"It is just about that."