him, looking at the clock.

"Our measurement of our time here," he began, "like yours, is based
on----"

"Excuse me," interrupted the Very Young Man. "I just want to know first
what time it is now?"

"It is in the fourth eclipse," said the Chemist with a twinkle.

The Very Young Man was too surprised by this unexpected answer to
question further, and the Chemist went on.

"We measure time by the astronomical movements, just as you do in your
world. One of the larger stars has a satellite which revolves around it
with extreme rapidity. Here at Arite, this satellite passes nearly
always directly behind its controlling star. In other words, it is
eclipsed. Ten of these eclipses measure the passage of our day. We rise
generally at the first eclipse or about that time. It is now the fourth
eclipse; you would call it late afternoon. Do you see?"

"How is the time gauged here?" asked the Big Business Man, indicating
the clock.

The instrument stood upon a low stone pedestal. It consisted of a
transparent cylinder about twelve inches in diameter and some four feet
high, surmounted by a large circular bowl. The cylinder was separated
from the bowl by a broad disc of porous stone; a similar stone section
divided the cylinder horizontally into halves. From the bowl a fluid was
dropping in a tiny stream through the top stone segment into the upper
compartment, which was now about half full. This in turn filtered
through the second stone into the lower compartment. This lower section
was marked in front with a large number of fine horizontal lines, an
equal distance apart, but of unequal length. In it the fluid stood now
just above one of the longer lines-the fourth from the bottom. On the
top of this fluid floated a circular disc almost the size of the inside
diameter of the cylinder.

The Chemist explained. "It really is very much like the old hour-glass
we used to have in your world. This filters liquid instead of sand. You
will notice the water filters twice." He indicated the two compartments.
"That is because it is necessary to have a liquid that is absolutely
pure in order that the rate at which it filters through this other stone
may remain constant. The clock is carefully tested, so that for each
eclipse the water will rise in this lower part of the cylinder, just the
distance from here to here."

The Chemist put his fingers on two of the longer marks.

"Very ingenious," remarked the Doctor. "Is it accurate?"