Under his direction I cut such gashes in the sides of the trees as would ensure that it should fall as we desired.  It had already a strong, natural tilt in the direction of the plateau, so that the matter was not difficult.  Finally I set to work in earnest upon the trunk, taking turn and turn with Lord John.  In a little over an hour there was a loud crack, the tree swayed forward, and then crashed over, burying its branches among the bushes on the farther side.  The severed trunk rolled to the very edge of our platform, and for one terrible second we all thought it was over.  It balanced itself, however, a few inches from the edge, and there was our bridge to the unknown.

All of us, without a word, shook hands with Professor Challenger, who raised his straw hat and bowed deeply to each in turn.

“I claim the honor,” said he, “to be the first to cross to the unknown land—­a fitting subject, no doubt, for some future historical painting.”

He had approached the bridge when Lord John laid his hand upon his coat.

“My dear chap,” said he, “I really cannot allow it.”

“Cannot allow it, sir!” The head went back and the beard forward.

“When it is a matter of science, don’t you know, I follow your lead because you are by way of bein’ a man of science.  But it’s up to you to follow me when you come into my department.”

“Your department, sir?”

“We all have our professions, and soldierin’ is mine.  We are, accordin’ to my ideas, invadin’ a new country, which may or may not be chock-full of enemies of sorts.  To barge blindly into it for want of a little common sense and patience isn’t my notion of management.”

The remonstrance was too reasonable to be disregarded. 
Challenger tossed his head and shrugged his heavy shoulders.

“Well, sir, what do you propose?”

“For all I know there may be a tribe of cannibals waitin’ for lunch-time among those very bushes,” said Lord John, looking across the bridge.  “It’s better to learn wisdom before you get into a cookin’-pot; so we will content ourselves with hopin’ that there is no trouble waitin’ for us, and at the same time we will act as if there were.  Malone and I will go down again, therefore, and we will fetch up the four rifles, together with Gomez and the other.  One man can then go across and the rest will cover him with guns, until he sees that it is safe for the whole crowd to come along.”

Challenger sat down upon the cut stump and groaned his impatience; but Summerlee and I were of one mind that Lord John was our leader when such practical details were in question.  The climb was a more simple thing now that the rope dangled down the face of the worst part of the ascent.  Within an hour we had brought up the rifles and a shot-gun.  The half-breeds had ascended also, and under Lord John’s orders they had carried up a bale of provisions in case our first exploration should be a long one.  We had each bandoliers of cartridges.