The Grange advance., 1874-04-15
Ventilation Of school Rooms.

Ventilation Of School Rooms.
We give below an analysis of the re-
marks Of DR.. Hewitt, Secretary of the
State. Board. Of Health, on this subject, to
the Teachers of our Public Schools:
The State Board sare making careful
study Of the ventilation of the State Insti-
.utions and Of school buildings. AS part
OF that work the Doctor has examined the
Red Wing school buildings. His conclu-
sions on the general subjecr are of so much
Importance that they deserve a larger au-
dience than that to which they were given.
He said there should be no mistake as to-
what is meant by venti ilation. False meth
DDS and ccnsequentafailu have come
from wrong ideas Of what can in this way
be done.
The object Of ventilation is tbe removal
Of the impurities added to the fir of inh.b-
tied buildings by the respiration and cuta-
neous Transportation Of pen ,/and by lights
and fires. 1t is accomplished by the pas
sage Of a stream Of pure tir taken from
the outside atmosphere.
1t cannot remove other Impurities which
come from uncle1n11hesF rooms, furni-
ture or persons; from solid or fluid nasti.
ness permitted to accumulate in dirty
houses. nor can it alone remove the efluvia
from sewers, cess pools. or drains allowed
to gain access to the interior Of the houses.
1t is "sver to be forgotten that ,e;h the most
perfect ventilatom possible, the air Of inhabited
buildings !. ntver 50 pure as the outside atmo.-
phere.
Ventilation is, therefore. but one method
Of cleanliness; to b successful it must be
used in common with other methods. This is
the invariab;e rule of nature. Its methods
in the house must spe the least possible
modification Of natural methods, the prin-
ciples are tho same. The last we expound
| in two natural laws,:tviz: L, the law of diff
fusion Of gasses. III, the law of the expau-
sion Of air By heatspnd its contraction by
cold. =
To illustrate the first Of these laws here
ere few facts: earbonic acid gas has .
specific gravity ofSSl.5, i. E: it is heavier
by one-hslf than conmon air in which it
exists in small compt tr.tive amount, 4 parts
in 10000; greatly II excess of this amount
it 10 dangerous and Sven fatal to life.
Now every adult person adds to the air
about fourteen cubic feet Of this gas every
t~enty-four hours. and the population of
our State in the same time gives to the air
5000, 900 cubic feet. Their fires and lights
add probably $4,000. 900 cubic feet more,
and domestic animals as much more, be-
side it is produced in variety of other
ways. So that ats least 3O,O00,O 900 cubic
feet Of this gas % i9to pur common air
from these sources alRsf, every day, and
yet its diffusion is 20 imm( (diate and perfect
that the differences ia its proportion to the
other elements~ef~'str~is pot diseernible.
This diffusion Of gases tak1 b place wherev-
er air penetrated through wood, mortar,
brick and even stone, and to great depths
in the earth
Familiar illustrations Of the operation of
the second law are found in the phenomena
of winds and storms.
The stmosphers is never entirely at rest,
it is always in ftate Of unrest, so that by
the operation Of these laws the composition
Of the external ar is always uniform. i,
The elements q the atmosphere are not
chemically CONT It is . mixture Of
easses holding later as vapors in suspen-
sion +; in this Wy it is most properly fitted
tor its work, to carry food to the myriad
forms Of organic llfe and material for the inf
mite variety of Changes which make up the
activities Of the tinorganic world. 1t is not
difhcult to understand that, shut up within
the walls Of : buading deprived ofits oxygen
By organic procsses and mixed constantly
with the emuvisf from body and breath, from
decaying anima4 and vegetable matter, from
f'res and lights it can become . very offen-
sive, foul, and Aoxious mixture, sort Of
stirabout' IS fetid sasses, vapors and
organic particles.
That even ii our best houses it is 80
made : direct a.use Of disease i proven by;
statistics. ss#
The great jority Of disease causss gain
sntraace TO su bodies through the air. sin-
ats, i.;e.#dhif flrsn under fyss ysars Of ags
faraisA int 1ittls bodies tAs most doll
ea3s & Z n asass e disea,s. These
flitslso nsrs - forty .psf