very _soft_,
and admirably adapted for many culinary purposes, and various processes
in different manufactures and the arts.

Fresh-fallen _snow_, melted without the contact of air, appears to be
nearly free from air. Gay-Lussac and Humboldt, however, affirm, that it
contains nearly the usual proportion of air.

Water from melted _ice_ does not contain so much air. _Dew_ has been
supposed to be saturated with air.

Snow water has long laid under the imputation of occasioning those
strumous swellings in the neck which deform the inhabitants of many of
the Alpine vallies; but this opinion is not supported by any
well-authenticated indisputable facts, and is rendered still more
improbable, if not entirely overturned, by the frequency of the disease
in Sumatra[12], where ice and snow are never seen.

In high northern latitudes, thawed snow forms the constant drink of the
inhabitants during winter; and the vast masses of ice which float on the
polar seas, afford an abundant supply of fresh water to the mariner.

_Spring Water_,

Includes well-water and all others that arise from some depth below the
surface of the earth, and which are used at the fountain-head, or at
least before they have run any considerable distance exposed to the air.
Indeed, springs may be considered as rain water which has passed through
the fissures of the earth, and, having accumulated at the bottom of
declivities, rises again to the surface forming springs and wells. As
wells take their origin at some depth from the surface, and below the
influence of the external atmosphere, their temperature is in general
pretty uniform during every vicissitude of season, and always several
degrees lower than the atmosphere. They differ from one another
according to the nature of the strata through which they issue; for
though the ingredients usually existing in them are in such minute
quantities as to impart to the water no striking properties, and do not
render it unfit for common purposes, yet they modify its nature very
considerably. Hence the water of some springs is said to be _hard_, of
others _soft_, some _sweet_, others _brackish_, according to the nature
and degree of the inpregnating ingredients.

Common springs are insensibly changed into mineral or medicinal springs,
as their foreign contents become larger or more unusual; or, in some
instances, they derive medicinal celebrity from the absence of those
ingredients usually occurring in spring