The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1882-12-16

medical topography supplies abundant affirmative
testimony. that moist subsoils. with surface ex-
posed 10 high temperatures and rapid evaporation,
present all the conditions necessary for the gen.
Grafton of this poison. In such places the ground
air may become contaminated and the poison
may be gathered in the strata of air near or on
the surface.
Ground air Is perhaps neither q less potential
nor a less frequent factor than ground water in
the causation of disease. The popular belief il
that the atmosphere ends where the ground be-
gins, but the fact is that the pores of the earth
when not filled with water are filled with air.
The quantity varies according to the nature of
the soil. The greater its porosity the more air it
can contain. Bubble soil, gravel or sand will
hold about 35 per cent of its mass of air. The
degree of humidity of a soil represents the amount
OF ground water, and soil saturation begins at the
lowest limit OF the air. Ground air contains a
larger proportion Of carbonic acid than either the
atmosphere or the ground water. and, at a few
feet below the surface, even more than is usually
found in badly ventilated dwellings. The guam
tIty is greater during the, winter than summer.
and increases with the depth, except during the
months of June and July, when the percentage
Is Inversed. Pettenkotfer concludes from his in
designations that the soil is the source Of this gas,
and is yielded by it to the ground water and
ground air, most freely to the latter and be be-
lieyes that it finds it's origin in organic processes
taking place in the soil. Huxley, Haeckel and
OtIlcE nave snOHu tudt OTSdulC litc tAlSle EVERY
where in every porous soil, as well as at the bot
tom of the sea. The more porous the soil, the
greater the quantity and more rapid the diffusion
OF air; the more active the processes of decay and
putrefaction, the greater the development oil low
organisms and the more abundant underground
life The ground is not only permeable, but the
air il contains is in constant motion. produced by
the pressure of the atmosphere and wind against
the surface by differences of temperature by
any and every cause which can produce move
ment and by the general law of diffusion OF
gases. The leakage of coal gas from street mains
has frequently been known to permeate the earth
beneath the street, penetrate walls, vaults and
foundations, and escape into dwellings at con-
siderable distances from the leak. So, also, has
the poison of disease been transported by under
ground conveyance. Whatever impurities and
pollutions may contaminate the ground air will
be difused by the current and constant change
going on. 1t may be impregnated with noxious
emanations generated either on or below the sur
face. All forms of filth, the excreta of animals,
and the processes and products OF putrefaction
collected upon or under the surface, or deposited
in vaults, eesspools or pits, constitute foci from
which deleteriOus exhalatiOns are disseminated
throughout the ground. In cities and other
places where people are massed in large numbers
In circumseribed areas, the soil water and ground
air will be, to a great degree, untitled for the
purposes of human life by such poisonous, and,
oftentimes, disease-bearing efiuvia. They are
more detrimental to life when received into the
system through the ground air than when con-
veyed through the atmosphere, because more con-
centrated, and mixed with larger percentages of
carbonic-acid gas. When exhaled into the free
atmosphere they are more easily diffused and
diluted, are blown away by the winds, and,
probably, more speedily oxldized and rendered
inert. But how can the ground air reach us?
Currents are created by differences Of tempera-
ture, and will be in the direction of the higher.
Ii should then constantly oscillate up and down
towards the atmosphere and into the earth. For
tunately for human life it does this, and in the
process the earth is ventilated, and the dele
terious constituents of the ground air are diffused
into space. But this movement and change of
air between the atmosphere and the earth is only
partial, and is Influenced by many conditions and
circumstances, such as the currents and force OF
the wind, formation of the soil, amount and fire.
quency OF precipitations, degree Of soil humidity.
and depth of soil saturatIon. 1t comes to US
when least expected, and when least resistance
can be offered to it's influences. 1t comes with
high percentage of carbonic-acid gas, with rela-
tiuely high humidity, and, perhaps, laden with
the germs of disease. 1t comes in our dwellings, in
our sleeping apartments, during the hours of rest
and repose, and is most apt to do SO when we are
most securely protecting ourselves from the ex-
ternal atmosphere, either because we fear its in
furious contaminations OF its chilling influences.
Ii Comes under the surface, passes through the
earth, and the permeable walls, foundations and
floors of our houses, and poisons the air we
uioutlC. Livery nOuoo unprotected Nv IOuuudtlOD5
and walls impermeable below the surface is a
draught-fue for the earth. The penetration Of
the air through the earth is promoted and facili-
tated by every such house. The warmer the air
inside, and the more securely protected against
the external and free atmosphere. the more rapid
the current Of ground-air through the foundations
and ground-6oors of such dwellings. 1t is a more
evil during the colder than during the
warmer seasons, because of the greater difference
The temperature of the houses and of the
ground air. "
1.-The air, both inside and outside of dwellings,
is always in motion, though this is not always
to our senses. Ventilation is effected
BY the constant interchange due to motion pro-
iuced by differences of temperature and by the
orce OF the wind, and is regulated by the porosity
If the walls and the size and number of the aper-
ures and architectural openings. The difference
IF temperature and the force of the wind fire.
luently supply the insuficiency of the one or the
By these means spontaneous ventilation
'ught to be sufficient for the purposes of health,
the greatest cleanliness and abstention
rom superduous pollutions are observed. There
ire, however, many circumstances and conditions
which interrupt and impede this necessary and
interchange.
I" Ventilation and draught are not the same.
Both imply motion of the air. Ventilation is the
necessary change of air in a closed space taking
,lace without perception of its movement.
)raught is the motion of air made manifest to
%ensation, and differs from wind only in intensity.
(Conchuded merit aOeek.)