Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1881-08-25


curry at 80 deg to IS deg.p" This is the
question asked by correspondent with
an observing turn of mind, and he refers
to two dates as exemplifying what he
means. These are the 18th and 18th OF
July, which we clearly remember
as TO their relative comfort and discom-
fort. We might reply to him briefly
!. that the thermometer does not tell all
the story as to the "bearability" of heat.
Other things come in to ameliorate or to
aggravate the temperature "a breeze or
quantity of moisture in the air. ''Rela-
tive humidity however, as you find it
in the weather reports, is the great
helper or the great offender. 1t is less
comfortable on hot moist day than on
hotter dry day.
On Tuesday, July IL, the first of the
days mentioned, the maximum temper
ATTIRE Cat the Signal Office) was 50 deg.
and the relative humidity (or moisture
in the air) ranged from 80 to 100 per
cent. with an effect by no means pleas
ant. 1t was a sultry, ''muggy'' day,
while on Thursday, the 14th, the Their
mometer rising to much higher point
GOA deg.) than on the 10Th, the hui
Nudity was much lower, ranging from
81 to GA per cent. only, leaving the heat
much more endurable. This latter day
was in fact remarkably pleasant day,
though over ten deg. hotter than the
former, and this was not due to a
stronger breeze, as the Signal Service
thermometer (wind measurer) registered
the same velocity of the winds-from
four to ten miles an hour on both days.
The sensible difference in the two days,
as respects the comfort of the body is,
therefore, traceable to the great humid
ity of the air on the 18th and the smaller
degree of moisture on the l4th.
The term srelative humidity.' or
humidity" it is true, does not refer to
the absolute quantity of moisture in the
air. In the language of meteorologists,
the term {" humidity denotes the de-
gree of its approach to saturation in the
air Tor containing as much as it can
hold). 1t expresses the proportion
which the amount of vapor actually
present in the air bears to that amount
which the air would hold if it was at the
point of saturation-when dew, mist or
rain is about to fall 'FRONT.' it,. When the
humidity is recorded as 100, the air is
completely saturated with moisture and
rain is imminent, but if reported at IS
it contains only three-fourths of the
amount requisite for saturation. For
tunately for Philadelphians, the average
humidity of the air here year in and year
out is under IS, and we are exempt from
the sultry climate of many places lying
even in higher ATTITUDES.
1t is of great Importance for those
who would profit by the daily Signal
service reports to bear in mind the sig
nificance of it's s. humidity column,
especially in the so-called "dog days"
The warmer the air is the larger be-
comes the quantity of invisible vapor it
is capable of sustaining and storing
away in the interstices between its
atoms. At the freezing point it can only
hold one one-hundredth part of it's own
weight of invisible vapor; at the tenn
perature of SO deg, one eightieth part of
its weight; at SO deg, one-fortieth part,
and for every addition of q deg. of
temperature its capacity is doubled. If
fully saturated at 81 deg. of tempera-
ture it contains 2.37 grains of aqueous
vapor per cubic foot; at 60 deg, 5.87
grains in each cubic foot, and at 80 deg.
of the thermometer 1881 grains A fall
of temperature from 80 deg. to GO deg.
throws down therefore nearly ) grains
of water for every cubic foot of air thus
chilled. A cubic foot of saturated air
under average pressure and tempera-
ture of 80 deg. weighs 495 grains (Troy).
of which 148 grains are pure aqueous
vapor. With the tenn perature verging
on 100 deg, as it sometimes does in our
"water waves,'' the atmosphere, at
sataration, contains as much as 10 81
grains of water to the cubic foot; from
which some idea may be gathered of
the enormous rain fall possibilities of
tropical clouds, which, heated up di-
rectly under the fierce sun, are replete
with evaporation from equatorial seas.
AS these watery particles offer resist
ance to the heat of both the earth and
air beneath them, which is seeking to
escape by radiation into the upper at
mosphere, they thus effectually prevent
the cooling of the soil and of the lower
aerial strata. While the s'relative hui
midity' data in the Weather Bureau
bulletins do not give the absolute
amount of vapor in the air, neverthe-
less, when the percentages given are
high, or near 100, they show that the
molecules of yapor are coalescing over
head, and are forming with the air
atoms canopy above US winch inter-
cepts the heat of the earth in its attempt
TO fly into the clouds. The vapor pres
ent also prevents the body from throw
ing off the high cumulative temperature
thus engendered in our midsummer
weather depends upon several circum-
stances. Evaporation from the skin,
and lungs is perhaps the most impor-
tAnt means the body has of reducing its
surplus heat, as DR.. Max Won Petten-
koffer, the eminent Munich hygienist,
has shown by the use of an apparatus
for testing the quantity of water evap-
Grated by men and animals. His exper-
ilnents demonstrate that men at rest
evaporate about two pounds only during
twenty-four hours, but on day OF hard
work four and half pounds of water.
ain the first instance he says, "about
2,016 caloric units in the second, 4,4SO
had to leave the body in consequence of
evaporation" and he forcibly adds:
sThis explains how it can be that even
with the hardestwork our blood will not
become warmer, but sometimes even
cooler, and what powerful means of