."

"Then so you shall. You need no chart of directions now, since you
will have the inestimable advantage of my own guidance. From the first
I had determined that I would myself preside over your investigation.
The most elaborate charts would, as you will readily admit, be a poor
substitute for my own intelligence and advice. As to the small ruse
which I played upon you in the matter of the envelope, it is clear
that, had I told you all my intentions, I should have been forced to
resist unwelcome pressure to travel out with you."

"Not from me, sir!" exclaimed Professor Summerlee, heartily. "So long
as there was another ship upon the Atlantic."

Challenger waved him away with his great hairy hand.

"Your common sense will, I am sure, sustain my objection and realize
that it was better that I should direct my own movements and appear
only at the exact moment when my presence was needed. That moment has
now arrived. You are in safe hands. You will not now fail to reach
your destination. From henceforth I take command of this expedition,
and I must ask you to complete your preparations to-night, so that we
may be able to make an early start in the morning. My time is of
value, and the same thing may be said, no doubt, in a lesser degree of
your own. I propose, therefore, that we push on as rapidly as
possible, until I have demonstrated what you have come to see."

Lord John Roxton has chartered a large steam launch, the Esmeralda,
which was to carry us up the river. So far as climate goes, it was
immaterial what time we chose for our expedition, as the temperature
ranges from seventy-five to ninety degrees both summer and winter, with
no appreciable difference in heat. In moisture, however, it is
otherwise; from December to May is the period of the rains, and during
this time the river slowly rises until it attains a height of nearly
forty feet above its low-water mark. It floods the banks, extends in
great lagoons over a monstrous waste of country, and forms a huge
district, called locally the Gapo, which is for the most part too
marshy for foot-travel and too shallow for boating. About June the
waters begin to fall, and are at their lowest at October or November.
Thus our expedition was at the time of the dry season, when the great
river and its tributaries were more or less in a normal condition.

The current of the river is a slight one, the drop being not greater
than eight inches in a mile. No s