The philosophy of eating. By Albert J. Bellows, M.D.

SOURCES OF INORGANIC MATTER.

191

and purer regions of the atmosphere, it brings down
with it less of the organic impurities, but being in other
respects the same, cannot be injurious to health, as is
commonly supposed. It will not, however, quench
thirst unless melted before it goes into the mouth, the
loss of heat in melting counteracting entirely the natural effect of water, so that the natives of arctic regions,
according to the testimony of Captain Ross, "prefer
enduring the utmost extremity of thirst rather than
attempt to remove it by eating snow;" but after it is
melted it is as nearly pure as any water, and quenches
thirst as well.
Spring Water.
Water falling in rain on the surface of the earth
percolates through the soil and substratal gravel or
sand, till it comes down to an impervious stratum,
carrying with it of course all soluble substances that
have been taken up but not filtered out by the sand
through which it passes. It passes along this impervious substratum till it comes to some opening in a
valley, or remains to be obtained through a well. It
is of course affected by the salts of the soil, and by the
soluble minerals in the gravel, or sand, or rock through
which it passes, and the quality of the water depends
on the character of the soil and the gravel. If the soil
be thin and poor, and the foundation rock and gravel
be granite, as in New England, there are few soluble
salts or minerals to be taken up, and the water is pure;
but if the soil is rich, and the subsoil and rocks are