Finally they set off, and it was a sight to see the long procession of dry-land Tortoises heavily laden with savants, scientific instruments, Glow-Worms and Fire-Flies for signal service, provisions, Ants and Tumble-Bugs to fetch and carry and delve, Spiders to carry the surveying chain and do other engineering duty, and so forth and so on; and after the Tortoises came another long train of ironclads—­stately and spacious Mud Turtles for marine transportation service; and from every Tortoise and every Turtle flaunted a flaming gladiolus or other splendid banner; at the head of the column a great band of Bumble-Bees, Mosquitoes, Katy-Dids, and Crickets discoursed martial music; and the entire train was under the escort and protection of twelve picked regiments of the Army Worm.

At the end of three weeks the expedition emerged from the forest and looked upon the great Unknown World.  Their eyes were greeted with an impressive spectacle.  A vast level plain stretched before them, watered by a sinuous stream; and beyond there towered up against the sky along and lofty barrier of some kind, they did not know what.  The Tumble-Bug said he believed it was simply land tilted up on its edge, because he knew he could see trees on it.  But Professor Snail and the others said: 

“You are hired to dig, sir—­that is all.  We need your muscle, not your brains.  When we want your opinion on scientific matters, we will hasten to let you know.  Your coolness is intolerable, too—­loafing about here meddling with august matters of learning, when the other laborers are pitching camp.  Go along and help handle the baggage.”

The Tumble-Bug turned on his heel uncrushed, unabashed, observing to himself, “If it isn’t land tilted up, let me die the death of the unrighteous.”

Professor Bull Frog (nephew of the late explorer) said he believed the ridge was the wall that inclosed the earth.  He continued: 

“Our fathers have left us much learning, but they had not traveled far, and so we may count this a noble new discovery.  We are safe for renown now, even though our labors began and ended with this single achievement.  I wonder what this wall is built of?  Can it be fungus?  Fungus is an honorable good thing to build a wall of.”

Professor Snail adjusted his field-glass and examined the rampart critically.  Finally he said: 

“’The fact that it is not diaphanous convinces me that it is a dense vapor formed by the calorification of ascending moisture dephlogisticated by refraction.  A few endiometrical experiments would confirm this, but it is not necessary.  The thing is obvious.”

So he shut up his glass and went into his shell to make a note of the discovery of the world’s end, and the nature of it.

“Profound mind!” said Professor Angle-Worm to Professor Field-Mouse; “profound mind! nothing can long remain a mystery to that august brain.”