[ 26]. PR 
cultivated life—to all of which you would nevertheless prefer a refreshing 
draught of cold water—there emerges in the plain before your astonished 
eyes a beautiful lake. Its guriace looks like os the wind moves but 
= EL eo 
Menon of mirage 
e high plain, with eel horizon, and but slight undula- 
groun 
y, hard ground, either quite barren, or but coated with parched 
isolated vegetation, like the short buffalo grass. 
3. Dry and ngs aresees ai aclear sky. On such days, and less in 
the morning and evening, but rather when the sun has the most power, 
mirage is the most frequent and pe plainest. 
4. A slight hollow in the he ey plain, however insignificant it may 
be, producing a background. Where this low background is interrupted 
by. the horizon, on that place the mirage grows more dim and disappears 
entirely 
The distance of several miles from the stand of the observer. The 
nearer one approaches, the more indistinct becomes the mirage, and it 
changes at last into a climmering of the air, such as can be seen on hot. 
summer days upon dry, solid, macadamized roads, from which the rays of 
the sun are powerfully reflected. 
he mirage is therefore the effect of a strong reflection of the rays of 
the sun from the ground, seen out of a certain distance, on certain locali- 
ties 
“8 That esi being near the mirage, as trees, animals, men, Ses are 
seen double, can also be explained by the following law of reflec 
When two strata of air, one of common middle temperature “me ea 
and the other hotter, meet together, an observer, standing also in a com- 
mon temperature and looking at an object near where the two strata meet, 
will see that. object double, directly in the stratum of common air, in which 
he stands himself, and indi rectly by reflected light in the hotter stratum. 
The direct image will stand upright; the reflected one inverted. 
But let us return to our carav While we were travelling to-day over 
the lonesome. plain , men and canals ane tired and exhausted, on the 
rising of a hill before us quite suddenly appeared a number of savage: 
looking riders on horseback, which at first sight we took for Indians; a 
their covered heads convinced us soon of ou - mistake, because Indi 
never wear hats of any kind: it was a band of Ciboleros, or Mexican Bf. 
falo hunters, dressed in leather or blankets, aed with bows and.arrows 
and a lance—sometimes, too, with a gun—and leading along a large train of 
jaded pack animals. ‘Those Ciboleros are generally poor Mexicans from 
the frontier settlements. of New Mexico, and. by their os We expeditions 
into the buffalo regions they provide themselves with meat 
for their own Aaa and for sale. Their pea acsacty is the lance, 
—_ 
