breeze blows, or, what is more common, close up tight the adobe
house in the morning and remain indoors until the intense heat
from the scorching sun penetrates the thick walls, which causes
the inmates to move out. In the cool of the evening they visit
and transact business and when the hour comes for retiring go to
bed on cots made up out of doors where they sleep until morning,
while the house is left open to cool off during the night. This
process is repeated every day during the hot summer months and is
endured without complaint.

The natives, also, take advantage of the dry air to operate a
novel method of refrigeration. The cloth covered army canteen
soaked in water and the handy water jug of the eastern harvest
field wrapped in a wet blanket are familiar examples of an
ineffectual attempt at refrigeration by evaporation. But natural
refrigeration find its best illustration in the arid regions of
the southwest by the use of an olla, which is a vessel made of
porous pottery, a stout canvas bag or a closely woven Indian
basket. A suitable vessel is selected, filled with water and
suspended somewhere in midair in the shade. If it is hung in a
current of air it is all the better, as any movement of the
atmosphere facilitates evaporation. A slow seepage of water
filters through the open pores of the vessel which immediately
evaporates in the dry air and lowers the temperature. The water
in the olla soon becomes cold and if properly protected will
remain cool during the entire day.

The dry air also acts as a valuable preservative. During the
winter, when the weather is cool but not freezing, if fresh meat
is hung out in the open air, it will keep sweet a long time. A