23 
THE WATER WE DRINK. 
(Illustrated by the Lantern). 
By HARRI HE A P, M.Sc., F.I.C., F.C.S. October 26th, 1915. 
The most striking and yet the most fascinating phenomena 
of nature are wrought by water, and without it life itself 
would be extinct. In a perfectly pure state water was never 
met with in nature, and could only be so obtained by the 
most refined operations. Impurities in water were derived 
from the materials— solid, liquid, or gaseous — with which it 
came in contact, and they might be present either in a state 
of solution or suspension or in both conditions ; but owing 
to the great solvent powers of water all its natural forces 
contained matters in both states. Waters might be con- 
veniently classified according to their origin : — (a), rain, snow, 
hail, hoarfrost, and dew, containing only impurities which 
they derived from the atmosphere ; (b), upland surface waters, 
which contained chiefly the remnants of decomposing vege- 
table matter ; and (c,) surface waters from cultivated land 
or partly cultivated land which were rich both in organic 
matter and living organisms. Shallow well waters were similar 
in their nature to surface waters, but deep wells generally 
offered the characteristics of mineral waters. These — thermal, 
saline, sulphated, alkaline, iron, or chalybeate — were interest- 
ing more as medicinal waters than as types of the so-called 
drinking waters. 
The chief sources of drinking supplies were either surface 
waters, lake waters, well waters, or artesian well waters. 
Upland surface, cultivated land, and shallow well waters 
presented more or less the same features ; whilst another 
class, with similar properties, was formed by the deep well 
and the artesian well waters. Primitive people draw their 
supplies from the rivers, wells, lakes, or springs, but where 
these supplies were periodic they had either to seek other 
supplies or resort to storage in times of plenty. The Car- 
thaginians and the Romans drew their supplies direct from 
the freshly-thawed waters of the high mountains, and led 
them down to their cities in huge aqueducts. In England 
we generally resorted to artificial reservoirs, but of late we 
had bridled the natural lakes and conducted the waters, 
which were, so to speak, pure supplies, by the less picturesque 
