Year: 1879

RluoerI o0dtvui nhHss


There was an excellent paper on
this subject published in the Ninth
Report of the State Board of Health
for Massac chusetts, written By Prof.
VIM. r. Nichols, of the Mass. In.
stitute Of Teachnology, and as 1t Is
not readily accessible to your read
ers, and too long for insertion as a
whole, the following epitome of it,
giving its more essential points,
with other ideas of the writer, may
Interest your readers:


1t often becomes necessary for
consumers to apply filters in their
houses. These are of two kinds.
First, a vase or receptacle contain
ing one or more gallons of water, to
be allied at intervals or by autom-
alto supply from the service pipes
and containing the filtering mater
ial properly disposed for the per-
t,,,i isttiioIi Of the water. And second,
small nuzzles to be screwd on to the
taps, something made invertible
Tor cleansing. The latter are SIM
pIe strainers, and as they contain
within their limited space very
small quantity of filtering material,
and as the water is expected to pass
through them quite rapidly, their
action is but very imperfect even as
strainers, and as they rapidly ac-
cumulate foreign matter, if any
such exists and they are efficient in
any degree, they need cleansing
eyery day, or even oftener in hot
weather. Otherwise the contents,
il organic, ferment and begin to de-
cav, and thus become even more
dangerous than the same matter
was when fresh and diluted by the
water which brought it. The diff
Guilty of enforcing this cleansing at
such frequent intervals in an or
dinary household renders the util.
ity of such so-called filters a very
doubtful matter. In fact, with or
dinary usage, they would be likely
to do more harm than good. A bag
Of cotton or flannel closely woven
and tied to the faucet would be a
safer device, because the foalness
of this bag would be visible and at
tract attention. Moreover, its
cleansing is easily effected by turn
ing it inside out. If made as large
"a an octave volume it would let
through water fast enough for con-
veniepce, and if made pointed at
thee Jottom the water oozing
through its sides would all be col
iected there in one stream.


The portable vessels used as fit
ers are of various styles and filled
with various materials. If sand
alone can be used, the action is
simply mechanical, removing the
solid matter as strainer, and there
fore subject to clogging and need
ing renewal and cleansing at inter-
walls, depending on the size and con.
tents of the apparatus compared
with the quantity of work done by
it. These are also likely to be
harmful if not frequently cleansed.
Animal charcoal, from bones, has
been largely used ,and more recently
spongy iron, both of which SUBJ
stances act chemically by the oxy-
gen contained in their pores and
constantly renewed from the air,
burning up as it were, such parts
of the organic matter as are the
most combustible by nature. But
these filters also eau be overwork-
ed, overcharged, and will not work
indefinitely without cleansing and
renewal, though far more efficient
In that respect tnan simple sand
filters.


There is a very simple filter used
in Egypt for removing silt from
the Nile water and cooling it at the
same time. A large jar OF unglazed
pottery, holding ten gallons or
more, with a pointed bottom, Is
supported on wooden frame
some two feet above the floor and
filled with water. The contents
percolate through the pores of the
vessel and drop from Its base into
another jar, of glazed ware, placed
beneath it, and the water thus fiji
tered is found to be not only clear,
but some 50 or 1Oo cooler than the
air, for The climate is so dry as to
promote a rapid evaporation from
the surface Of the porous jar, car
rying off q large amount of heat
in the process. There is no
reason why this apparatus should
not succeed we'll upon our
Western rivers, though the abund-
ance of ice in this country is prob
ably more efficient as a cooling
agent than the evaporation from an
atmosphere already half saturated
with vapor as ours is. Perhaps
Western men are attached to the
peculiar color of the Mississippi,
but they would soon become accus-
toned to transparent water, and
probably might prefer 1t in the end.
The ease with which this jar can
be cleaned out before filling. and
its cheapness, recommend its trial,
especially on steamboats, and at
river towns where the water is gen.
orally taken directly from the river
a. In Egypt. This sort of filtration
is simply mechanical, Of course, the
water in question containing no sp.
preciable amount of organic mat
r s1s. Thheera are various corubina-
tions of charcoal, sand, sponges,
and spoRgy iron used by the manu-
facturers of domestic filters; but al
though efficient to some extent in
removing organic matter which is
held by the water in solution, their
continued efficiency depends so
much upon the attention of the ler-
son using them, in renewing or
cleansing their contents at frequent
intervals, that their usefulness is
thereby impaired for the average
consumer. Tere are, of course, GER
tain quantities of organic matter
contained in our river and pond wa
ters In mechanical suspension, both
vegetable and animal forms, living
and dead. Such matter can be re-
moved by the flannel bag or any
fine sand filter. 1t does not often
occur in sufficient quantities to
do any harm. The writer has here
fnfnra given In fhpaa cnlumns a