doctor.

They soon gave up the chase, however, for the lights were
continually moving and frequently went out. While groping in the
growing darkness, they came upon a brown object about the size of
a small dog and close to the ground. It flew off with a humming
insect sound, and as it did so it showed the brilliant
phosphorescent glow they had observed.

"That is a good-sized fire-fly," said Bearwarden. "Evidently the
insects here are on the same scale as everything else. They are
like the fire-flies in Cuba, which the Cubans are said to put
into a glass box and get light enough from to read by. Here they
would need only one, if it could be induced to give its light
continuously."

Having found an open space on high ground, they sat down, and
Bearwarden struck his repeater, which, for convenience, had been
arranged for Jupiter time, dividing the day into ten hours,
beginning at noon, midnight being therefore five o'clock.

"Twenty minutes past four," said he, "which would correspond to
about a quarter to eleven on earth. As the sun rises at
half-past seven, it will be dark about three hours, for the time
between dawn and daylight will, of course, be as short as that we
have just experienced between sunset and night."

"If we stay here long," said the doctor, "I suppose we shall
become accustomed, like sailors, to taking our four, or in this
case five, hours on duty, and five hours off."