that way! Only with me it's like ants
crawling up and down my back."

"O-o-o-oh!" again sighed Genevieve. "It--it so overpowers one!"

"It's sure some canyon," admitted her husband. "That French artist Dore
ought to have seen it."

"If only we had a copy of Dante's Inferno to read here on the brink!"
she whispered.

"It always reminds me of Coleridge's poem," murmured Isobel, and she
quoted in an awed whisper:

Where Alph, the sacred river, ran
Through caverns measureless to man,
Down to the sunless sea.

"Fortunately for us, this is a canyon, not a string of measureless
caverns," said Blake. "It can be measured, one way or another. If I
had a transit, I could calculate the depth at any point where the
water shows--triangulate with a vertical angle. But it would cause a
long delay to send on for a transit. We shall first try to chain down
at that gulch break."

Genevieve shrank back from the verge of the precipice and drew the
others after her.

"Dear!" she exclaimed, "I did not dream it was so fearful. One has to
see to realize! You will not go down--promise me you will not go
down!"

"Now, now, little woman," reproached Blake. "What's become of my
partner?"

"But baby--? If you should leave him fatherless!"

"Better that than for him to have a father who is a quitter! Just
wait, Sweetheart. That break looks much less overwhelming than these
sheer cliffs. You know I shall not attempt anything foolhardy. If it
is not possible to get down without too great risk, I shall give it up
and send for a transit."

"Oh, will you?" exclaimed Isobel, hardly less apprehensive than his
wife. "Why not wait anyway until you can send for your transit?"

"Because I cannot triangulate the bottom within half a mile upstream
from where the tunnel would have to be located. That roar and the
wildness of the water wherever we can see it is proof that it is
flowing down a heavy grade. At the point where I triangulated it might
be above the level of Dry Mesa, and way below the mesa here at the
tunnel site."

"You could triangulate at the first place where the bottom can be
seen, beyond here," suggested Genevieve.

"Suppose it proved to be lower than Dry Mesa, wouldn't that still
leave us up in the air?" he asked. "Like this--"

He pulled out his notebook and drew a rough sketch.

[Transcriber's Note: an illustration showing "Elevation of bench-mark
at foot of chute in Dr