ed with putrid vegetable matter
and animalculae, would be very likely to generate fevers and dysenteries
if taken into the stomach without purification. It should therefore be
thoroughly boiled, and all the scum removed from the surface as it
rises; this clarifies it, and by mixing powdered charcoal with it the
disinfecting process is perfected. Water may also be purified by
placing a piece of alum in the end of a stick that has been split, and
stirring it around in a bucket of water. Charcoal and the leaves of the
prickly pear are also used for the same purpose. I have recently seen a
compact and portable filter, made of charcoal, which clarifies the
water very effectually, and draws it off on the siphon principle. It
can be obtained at 85 West Street, New York, for one dollar and a half.
Water may be partially filtered in a muddy pond by taking a barrel and
boring the lower half full of holes, then filling it up with grass or
moss above the upper holes, after which it is placed in the pond with
the top above the surface. The water filters through the grass or moss,
and rises in the barrel to a level with the pond. Travelers frequently
drink muddy water by placing a cloth or handkerchief over the mouth of
a cup to catch the larger particles of dirt and animalculae.

Water may be cooled so as to be quite palatable by wrapping cloths
around the vessels containing it, wetting them, and hanging them in the
air, where a rapid evaporation will be produced. Some of the
frontier-men use a leathern sack for carrying water: this is porous,
and allows the necessary evaporation without wetting.

The Arabs also use a leathern bottle, which they call _zemsemiyah_.
When they are _en route_ they hang it on the shady side of a camel,
where the evaporation keeps the water continually cool.

No expedition should ever set out into the plains without being
supplied with the means for carrying water, especially in an unknown
region. If wooden kegs are used they must frequently be looked after,
and soaked, in order that they may not shrink and fall to pieces. Men,
in marching in a hot climate, throw off a great amount of perspiration
from the skin, and require a corresponding quantity of water to supply
the deficiency, and unless they get this they suffer greatly. When a
party makes an expedition into a desert section, where there is a
probability of finding no water, and intend to return over the same
track, it is well to carry water as f