The hiss of escaping air as the water came into the tanks was heard, and Matt secured the hatch and came down the ladder.
The hissing ceased suddenly.
"We're ten feet down, Matt," reported Clackett through the tube.
"Take the wheel, Tirzal," said Matt.
With head under the periscope hood and one hand on the wheel, Tirzal rang for slow speed ahead. Matt and Jordan likewise gave their attention to the periscope mirror and watched, with curious wonder, while the tropical river unfolded beneath their eyes like a moving picture.
The Izaral was bank-full. As the Grampus rounded the northern bluff and swerved into the river channel, the high, steep banks, covered with dense foliage, resembled a narrow lane with a blank wall at its farther end. When the boat pushed into the stream, however, and fought the current for three or four hundred yards, the seemingly blank wall gave place to an abrupt turn.
The submarine took the turn and entered upon another stretch of the lane.
This part of the river was as perfect a solitude as though removed thousands of miles from human habitations. At a distance of perhaps two miles from the coast the high banks dwindled to low rises, and on each side was an unbroken forest; the banks were overflowed; the trees seemed to grow out of the water, their branches spreading across so as almost to shut out the light of the sun and were reflected in the water as in a mirror.
Birds of gaudy plumage fluttered among the trees, and here and there in a bayou alligators could be seen stretching their torpid bodies in the black ooze.
Tirzal kept his eyes glued to the periscope. The channel was crooked and dangerous, and a moment's neglect might hurl the submarine into a muddy bank, causing trouble and delay, if not actual peril.