16 EXPLORATION OP THE CANONS OF THE COLORADO. 
ening roar of the water is loud and constant, and I lie awake with thoughts 
of the morrow and the canons to come, interrupted now and then by char 
acteristics of the scenery that attract my attention. And here I make a 
discovery. On looking at the mountain directly in front, the steepness of 
the slope is greatly exaggerated, while the distance to its summit and its true 
altitude are correspondingly diminished. I have heretofore found that to 
properly judge of the slope of a mountain side, you must see it in profile. 
In coming down the river this afternoon, I observed the slope of a particular 
part of the wall, and made an estimate of its altitude. While at supper, I 
noticed the same cliff from a position facing it, and it seemed steeper, but 
not half as high. Now lying on my side and looking at it, the true propor 
tions appear. This seems a wonder, and I rise up to take a view of it stand 
ing. It is the same cliff as at supper time. Lying down again, it is the 
cliff as seen in profile, with a long slope and distant summit. Musing on 
this, I forget "the morrow and the canons to come." I find a way to esti 
mate the altitude and slope of an inclination as I can judge of distance along 
the horizon. The reason is simple. A reference to the stereoscope will 
suggest it. The distance between the eyes forms a base-line for optical 
triangulation. 
June 1. To-day we have an exciting ride. The river rolls down the 
canon at a wonderful rate, and, with no rocks in the way, we make almost 
railroad speed. Here and there the water rushes into a narrow gorge; the 
rocks on the side roll it into the center in great waves, and the boats go 
leaping and bounding over these like things of life. They remind me of 
scenes witnessed in Middle Park ; herds of startled deer bounding through 
forests beset with fallen timber. I mention the resemblance to some of the 
hunters, and so striking is it that it comes to be a common expression, "See 
the black-tails jumping the logs." At times the waves break and roll over 
the boats, which necessitates much bailing, and obliges us to stop occasion 
ally for that purpose. At one time, we run twelve miles in an hour, stop 
pages included. 
Last spring, I had a conversation with an old Indian named Pa'-ri-ats, 
who told me about one of his tribe attempting to run this canon. "The 
rocks," he said, holding his hands above his head, his arms vertical, and 
