The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1913-03-02

week or two when patches OF snow
were observed to maintain high hui
midity conditions.
In January, 1913, more fogginess anc
smokiness occurred than In any othel
month during the past forty years
thero being eighteen gloomy days. Dur
ing these January fogs the wind aver
from southcrly directions, 1t also is Of
interest to note that from tho 9th tt
the 18th inclusive, when only one lighl
fog occurred. the total daily number OF
miles of wind blowing across Salt Lake
City averaged 293; but during the
continuous foggy, smoky weather from
the 10Th to the 3lst inclusive, the av
erage daily number Of miles of wind
was only los, or only about one-third
as much.
The total amount of moisture con
tanned in the atmosphere during oul
winter mornings, with relative humidl
ties of about 10 per cent and average
temperatures around 30 degrees, is
about Ia grains per cubic foot, by &C
tual weight. Not all OF this can be
condensed on smoke and smelter dust
particles, or absorbed by the hygro'
scopic sulphur dust OF acids, in the
free air conditions, yet, II only one
fourth of 1T appears As visible moisture
| (Which is doubtless conservative esti-
mate for many mornings), at least that
amount, 0.3 grains of new sulphuric
acid, would be produced for every cubic
foot Of air from the ground up to the
average limit of the smoke and SCOT
This, it must be remembered, is the
amount added to that already contained
in the air, thus making tho total
amounts very great, if it is not regu-
larly precipitated by transforms, or
driven out of the valley by windstorms.
Effect of Moisture In Air.
If the hundreds of tons of sulphur
GUS SCOT suspended In the air over Salt
Lake City at any one time were per.
fectly dry it would cause but relative.
ly small percentage Of the detriment
that now occurs. Absolutely dry
smoke particles of whatever size they
may happen to be, would be very much
more buoyant than moisture coated
PARTICLES. and would not only float
throughout the atmosphere and have
less tendency to fall in sheets and
clouds upon the city, by reason of their
floating higher, would find themselves
in air whose movement is normally
from five to twenty times as rapid as
the movement Of surface air. And thus
would the dry dust-like SCOT be carried
beyond the city limits before it fell to
earth. Moreover, in q perfectly dry air,
where no moisture could appear on the
smoke particles by condensation, the
lower strata Of air would contain prac"
tically nothing but the coarser, heavier
particles; the finer and more trouble
some SCOT and dust occupying the
greater attitudes, finding as nearly sta.
Bile equilibrium high in the mir as the
heavier particles find in the lower,
denser air.
And so far as the smoke particles re.
main dry this natural distribution of
the coarser and finer particles occurs,
but unfortunately, with winter humidi-
ties in Salt Lake City of from 65 per
cent to 85 per cent of saturation, prob
ably no smoke particle, however
small, descends very far towards the
earth on It's return journey before 1t IS
cooled to the temperature Of the dew
point, and anpexes its full carrying ca
pacity of moisture.
Instantly then do We have the light
obstructing smoke particle Of say, one
three-thousandth Of an inch in diam.
eter increase In size to one thousandth
of an inch in diameter; that Is, rem
dcring an atmosphere clogged with
dry smoke and dust particles from the
smelter smoke and elsewhere, about
three times as Opaque with the moist
ure OF fog particles added. OF course,
limited to small streams of cold air
OF to small regions Of quiet air, the
fog area growing gradually. In M
ture it is also true that one dust
moisture particle will unite with
others, the tendency to coalesce being
limited only by the amount Of humid
ity available.
The condensations on the larger par
ticles may not Immediately increase
rs it does the smaller ones, yet the
increase will soon reach this dimen.
sion If there is sufficient humidity
available. Therefore, in considering
the actual sieht-carrying quality of
the air over the city alone. with an
air so dry that no cooling dust parti-
Gle could reach the dow point and
collect its moisture load, if we could
see on abject three blocks away, it is
in moist air, with all particles col"
lectng moisture. the same object
would be obscured beyond one block
or Just one-third as far.
Part Played by Mineral Oils.
Moreover, we have it from eminent
meteorologists and engineers, that the
unconsumcd mineral oils in the fuel
smoke forms an oil film around every
fog or moisture particle which greatly
delays evaporation. renders the fog
more tenacious and much moro dur.
able than plain, common country or
seashore fog. The moist observation,
now Of triple density, is therefore be-
come an object Of far greater perma-
nency than the former mere mass of
segregated, separated, unbonded smoke
PARTICLES.
The sulphur oxide gas. rendered so
abundant in our atmosphere by the
smelters, coming in contact with the
moisture particles, instantly forms sui.
phuric acid, as We have previously
pointed out. In low humidities, when
there is q dearth Of moisture, the
new sulphuric acid is in condensed
form; but during high humidities, with
abundant moisture, the moro dilute
sulphuric acid naturally results, at
first.
However, unless the relative humid
ity is very close to 100 per cent, OF
actual satnration, it is improbable that
the sulphuric acid poison is very much
diluted This is because Of the great
and unquenchable thirst the suIphuric
acid and the sulphur dioxide has for