But that greenish tint--to what was it due?
To a dense tropical vegetation maintained by a low atmosphere, a mile or so in thickness?
Possibly.

But this was another question that could not be answered at present.
Further on he could detect here and there traces of a decidedly ruddy tint.

Such a shade he knew had been already detected in the _Palus Somnii_, near _Mare Crisium_, and in the circular area of _Lichtenberg_, near the _Hercynian Mountains_, on the eastern edge of the Moon.

To what cause was this tint to be attributed?
To the actual color of the surface itself?
Or to that of the lava covering it here and there?
Or to the color resulting from the mixture of other colors seen at a distance too great to allow of their being distinguished separately?
Impossible to tell.
Barbican and his companions succeeded no better at a new problem that soon engaged their undivided attention.

It deserves some detail.
Having passed _Lambert_, being just over _Timocharis_, all were attentively gazing at the magnificent crater of _Archimedes_ with a diameter of 52 miles across and ramparts more than 5000 feet in height, when Ardan startled his companions by suddenly exclaiming: "Hello! Cultivated fields as I am a living man!" "What do you mean by your cultivated fields ?" asked M'Nicholl sourly, wiping his glasses and shrugging his shoulders.
"Certainly cultivated fields!" replied Ardan.