gravitational force of the Earth, almost three times as great as that
of Mars, but the two Martian scientists struggled to their feet as the
Terrestrials entered.

"As you were, fellows--lie down again and take it easy." Brandon
suggested in the common Interplanetarian tongue. "We'll be away from
here very soon, then we can ease off."

"We greet our friends standing as long as we can stand," and, towering
a full two feet above Brandon's own six-feet-two, Alcantro and Fedanzo
in turn engulfed his comparatively tiny hand in a thick-shelled paw
and lifted briefly the inner lids of quadruply-shielded eyes. For the
Martian skin is not like ours. It is of incredible thickness; dry,
pliable, rubbery, and utterly without sensation: heavily lined with
fat and filled throughout its volume with tiny air-cells which make
it an almost perfect non-conductor of heat and which prevent absolutely
the evaporation of the precious moisture of the body. For the same
reasons their huge and cat-like eyes are never exposed, but look
through sealed, clear windows of membrane, over which may be drawn at
will one or all of four pairs of lids--lids transparent, insensible,
non-freezable, air-spaced insulators. Even the air they exhale carries
from their bodies a minimum of the all-important heat and moisture,
for the passages of their nostrils do not lead directly to the lungs,
as do ours. They are merely the intakes for a tortuous system of
tubes comprising a veritable heat-exchanger, so that the air finally
expelled is in almost perfect equilibrium with the incoming supply
in temperature and in moisture content. A grayish tan in color, naked
and hairless--though now, out of deference to Terrestrial conventions,
wearing light robes of silk--indifferent alike to any extreme of heat or
cold, light or darkness: such were the two forbidding beings who arose
to greet their Terrestrial friends, then again reclined.

"I suppose that you have been given to drink?" Westfall made sure that
they had been tendered the highest hospitality of Mars.

"We have drunk full deeply, thanks; and it was not really necessary,
for we drank scarcely three weeks ago."

Brandon and Westfall turned then and greeted the two Venerians,
as different from the Martians as they were from the Terrestrials.
Of earthly stature, form, and strength, yet each was encased in a
space-suit stretched like a drum-head, and would live therein or in
the special Venerian rooms of the ves