30 REGION OF GYPSUM. 
that might be taken by hostile savages in 
such a locali 
After the fire had raged with great violence 
for a few hours, a cloud suddenly obscured 
the horizon, which was almost immediately 
followed by a refreshing shower of rain: a 
phenomenon often witnessed upon the Prai- 
ries after an extensive conflagration; and 
affording a practical exemplification of Pro- 
fessor a s celebrated theory of artificial 
showers 
We now continued our journey without 
further trouble, except that of being still forced 
out of our proper latitude by the northern 
bearing of the Canadian. On the 30th of 
May, however, we succeeded in ‘doubling’ 
the spur of the Great North Bend. Upon as- 
cending the dividing ridge again, which at 
this point was entirely destitute of timber, a 
‘prairie expanse’ once more greeted our view. 
This and the following day, our route lay 
through a region that abounded in gypsum, 
from the finest quality down to ordinary plas- 
ter. On the night of the 31st we encamped 
on a tributary of the North Fork, which we 
called Gypsum creek, in consequence of its 
being surrounded with vast quantities of that 
substance. 
Being compelled to keep a reckoning of 
our latitude, by which our travel was partly 
governed, and the sun being now too high at 
noon for the use of the artificial horizon, we 
had to be guided entirely by observations of 
the meridian altitude of the moon, planets, or 
