trange thing is, that we all seem to have been impressed
the same way."

Concluding that they must have been mistaken, they continued on their
journey.

All about they heard a curious humming, as that of bees, or like the
murmuring of prayers in a resonant cathedral. Thinking it was the wind
in the great trees that grew singly around them, they paid no attention
to it until, emerging on an open plain and finding that the sound
continued, they stopped.

"Now," said Bearwarden, "this is more curious than anything we found on
Jupiter. Here we have an incessant and rather pleasant sound, with no
visible cause."

"It may possibly be some peculiarity of the grass," replied Cortlandt,
"though, should it continue when we reach sandy or bare soil, I shall
believe we need a dose of quinine."

"I FEEL perfectly well," said Ayrault; "how is it with you?"

Each finding that he was in a normal state, they proceeded, determined,
if possible, to discover the source from which the sounds came.
Suddenly Bearwarden raised his gun to bring down a long-beaked hawk;
but the bird flew off, and he did not shoot. "Plague the luck!" said
he; "I went blind just as I was about to pull. A haze seemed to cover
both barrels, and completely screened the bird."

"The Callisto will soon be hidden by those trees," said Cortlandt. "I
think we had better take our bearings, for, if our crack shot is going
to miss like that, we may want canned provisions."

Accordingly, he got out his sextant, took the altitude of the sun, got
cross-bearings and a few angles, and began to make a rough calculation.
For several minutes he worked industriously, used the rubber at the end
of his pencil, tried again, and then scratched out. "That humming
confuses me so that I cannot work correctly," said he, "while the most
irrelevant things enter my mind in spite of me, and mix up my figures."

"I found the same thing," said Bearwarden, "but said nothing, for fear
I should not be believed. In addition to going blind, for a moment I
almost forgot what I was trying to do."

Changing their course slightly, they went towards a range of hills, in
the hope of finding rocky or sandy soil, in order to test the sounds,
and ascertain if they would cease or vary.

Having ascended a few hundred feet, they sat down near some trees to
rest, the musical hum continuing meanwhile unchanged. The ground was
strewn with large coloured crystals, apparently rubies, sapphires, and