No wonder.

The travellers found themselves now in a night that had plenty of time not only to become black itself, but to steep everything connected with it in palpable blackness.

This was the night 354-1/4 hours long, during which the invisible face of the Moon is turned away from the Sun.

In this black darkness the Projectile now fully participated.

Having plunged into the Moon's shadow, it was as effectually cut off from the action of the solar rays as was every point on the invisible lunar surface itself.
The travellers being no longer able to see each other, it was proposed to light the gas, though such an unexpected demand on a commodity at once so scarce and so valuable was certainly disquieting.