o bottom,
and, by taking a series of vertical and horizontal angles from the top
edge, can measure the contour of the two sides, at the point crossed by
the survey line, with the nicest accuracy."

"How do you mean?" demanded Butler.

Harry proceeded to elaborate his explanation, patiently describing each
step of the intended operation, and making it perfectly clear that the
elaborate series of unnecessary measurements demanded could be secured
with the most beautiful precision.

"But," objected Butler, "when you have taken all those angles you will
have done only part of the work; you will still have to calculate the
length of the vertical and horizontal lines subtended by them--"

"A matter of about half an hour's work!" interjected Harry.

"Possibly," agreed Butler. "But," he continued, "I do not like your
plan at all; I do not approve of it; it is amateurish and theoretical,
and I won't have it. A much simpler and more practical way will be for
you to go down the _quebrada_ at the end of a rope, measuring as you
go."

"That is one way certainly," assented Harry; "but, with all submission,
Mr Butler, I venture to think that it will not be nearly so accurate as
mine. Besides, consider the danger. If the rope should happen to be
cut in its passage over the sharp edge of that rock--"

"Look here," interrupted Butler, "if you are afraid, you had better say
so, and I will do the work myself. But I should like you to understand
that timid people are of no use to me."

The taunt was unjust, for Harry was not afraid; but he was convinced
that his own plan was far and away the more expeditious and the more
accurate, also it involved absolutely no danger at all; while it was
patent to even the dullest comprehension that there was a distinct
element of danger attaching to the other, inasmuch as that if anything
should happen to the rope, the person suspended by it must inevitably be
precipitated to the bottom, where a mountain stream roared as it leaped
and boiled and foamed over a bed of enormous boulders.

Had Escombe been ten years older than he actually was he would probably
not have hesitated--while disclaiming anything in the nature of
cowardice--to express very strongly the opinion that where there were
two methods of executing a certain task, one of them perfectly safe, and
the other seriously imperilling a human life, it was the imperative duty
of the person with whom the decision rested to select the sa