i 62 
The Colorado River 
on the bank in their care, to be picked up by Captain Wilcox, 
who, going down on one of the fort steamers, had passed the 
Explorer, and offered to take these extra stores to the fort on 
his return. They were placed with the Cocopas by his direc¬ 
tion, an arrangement that better describes the relations of the 
steamboat people and the natives than anything that could be 
said about them. The fuel used was wood, of which there 
was great abundance along the shore, the hard, fine-grained 
mesquite making a particularly hot fire. The routine of ad¬ 
vance was to place a man with a sounding-pole at the bow, 
while Robinson, the pilot, had his post on the deck of the 
cabin, but the sounding was more for record purposes than to 
assist Robinson, who was usually able to predict exactly when 
the water would shoal or deepen. Later, Ives says: “If the 
ascent of the river is accomplished, it will be due to his skill 
and good management. “ Besides the ordinary shifting of the 
sands by the restless current, there was another factor occa¬ 
sionally to guard against. This was earthquakes. Sometimes 
they might change the depth of water on the lower river in the 
twinkling of an eye. On one occasion, a schooner lying in a 
deep part was found suddenly aground in three feet of water, 
with no other warning than a rumble and a shock. Heintzel- 
man, in one of his reconnoissances, discovered the adjacent 
land full of cracks, through which oozed streams of sulphurous 
water, mud, and sand, and Diaz, in 1540, came to banks of 
“hot ashes “ which it was impossible to cross, the whole 
ground trembling beneath his feet. At low water, even in the 
lower reaches of the river, a boat is liable to run aground often, 
and has to be backed off to try her fortune in another place. 
The bottom, however, is soft, the current strong, so no harm 
is done and the rush of water helps to cut the boat loose. One 
does not easily comprehend how sensitive a pilot becomes to 
every tremor of the hull in this sort of navigation. The 
quality of the boat’s vibration speaks to his nerves in a distinct 
language, and the suck of the wheel emphasises the communi¬ 
cation. 
The Explorer at length arrived at Yuma. Here the re¬ 
mainder of the party, including Dr. Newberry, having come 
