This mode
being for obvious reasons impracticable, cisterns are made, and rain
conducted to them through pipes leading from the roof. The water has thus
taken up all the dust, soot, and other impurities found upon the roof,
and, unless filtered, can not be considered desirable drink. The best
cistern will include a filter of some sort, and this is accomplished in
two ways. Either the cistern is divided into two parts, the water being
received on one side, and allowed to slowly filter through a wall of
porous brick, regarded by many as an amply sufficient means of
purification; or a more elaborate form is used, the division in such case
being into upper and under compartments, the upper one containing the
usual filter of iron, charcoal, sponge, and gravel or sand. If this water
has a free current of air passing over it, it will acquire more sparkle
and character; but as a rule it is flat and unpleasant in flavor, being
entirely destitute of the earthy salts and the carbonic-acid gas to be
found in the best river or spring water.
Distilled water comes next in purity, and is, in fact, identical in
character with rain-water; the latter being merely steam, condensed into
rain in the great alembic of the sky. But both have the curious property
of taking up and dissolving _lead_ wherever they find it; and it is for
this reason that lead pipes as leaders from or to cisterns should _never_
be allowed, unless lined with some other metal.
Pages:
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40