th asbestos, not to
keep the cold out, but the heat in. On the back of the dress there was a
square case, looking like a knapsack, containing the expanding
apparatus, which would furnish breathable air for an almost unlimited
time as long as the liquefied air from a cylinder hung below it passed
through the cells in which the breathed air had been deprived of its
carbonic acid gas and other noxious ingredients.

The pressure of air inside the helmet automatically regulated the
supply, which was not permitted to circulate through the other portions
of the dress. The reasons for this precaution were very simple. Granted
the absence of atmosphere on the moon, any air in the dress, which was
woven of a cunning compound of silk and asbestos, would instantly expand
with irresistible force, burst the covering, and expose the limbs of the
explorers to a cold which would be infinitely more destructive than the
hottest of earthly fires. It would wither them to nothing in a moment.

A human hand or foot--we won't say anything about faces--exposed to the
summer or winter temperature of the moon--that is to say, to its
sunlight and its darkness--would be shrivelled into dry bone in a
moment, and therefore Lord Redgrave, foreseeing this, had provided the
breathing-dresses. Lastly, the two helmets were connected, for purposes
of conversation, by a light wire, the two ends of which were connected
with a little telephonic receiver and transmitter inside each of the
head-dresses.

"Well, now I think we're ready," said Redgrave, putting his hand on the
lever which opened the outer door.

His voice sounded a little queer and squeaky over the wire, and for the
matter of that so did Zaidie's as she replied:

"Yes, I'm ready, I think. I hope these things will work all right."

"You may be quite sure that I shouldn't have put _you_ into one of them
if I hadn't tested them pretty thoroughly," he replied, swinging the
door open and throwing out a light folding iron ladder which was hinged
to the floor.

They were in the shade cast by the hull of the _Astronef_. For about ten
yards in front of her Zaidie saw a dense black shadow, and beyond it a
stretch of grey-white sand lit up by a glare of sunlight which would
have been intolerable if it had not been for the smoke-coloured slips of
glass which had been fitted behind the glass visors of the helmets.

Over it were thickly scattered boulders and pieces of rock bleached and
desiccated, an