member of the expedition.

"We ought to get there tomorrow, then," he said eagerly. Indoor life did
not appeal to him, even under such exciting circumstances. He peered at
Mercury through his binoculars. "Beginning to show up fine now."

The builder improved upon Van Emmon's example by setting up the car's
biggest telescope, a four-inch tube of unusual excellence. All three
pronounced the planet, which was three-fourths "full" as they viewed it,
as having pretty much the appearance of the moon.

"Wonder why there's always been so much mystery about Mercury?" pondered
the architect invitingly. "Looks as though the big five-foot telescope
on Mt. Wilson would have shown everything."

"Ask doc," suggested Smith, diplomatically. Jackson turned and hailed
the little man on the other side of the car. He looked up absently from
the scientific apparatus with which he had been making a test of the
room's chemically purified air, then he stepped to the oxygen tanks and
closed the flow a trifle, referring to his figures in the severely exact
manner of his craft. He crossed to the group.

"Mercury is so close to the sun," he answered the architect's question,
"he's always been hard to observe. For a long time the astronomers
couldn't even agree that he always keeps the same face toward the sun,
like the moon toward the earth."

"Then his day is as long as his year?"

"Eighty-eight of our days; yes."