New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1888-08-19
MYSTERIES OF MUGGINESS.
A PHASE OF SUMMER WEATHER.

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neither inolcgant dshabllle iced beverages phil
osophy profanity would sensibly assuage his mis-
cry the suspicion has stolen across the mind OF many
swetering mortal that something besides mere
caloric was making mischief with the weather Science
! now confirms these mlsgivings No reader Of Tho
Tribune for the last two years needs TO be told that
the trouble due to excessive humidity of the air
the presence OF two three drops OF water in
the form Of Invisible vapor than usually lurk In every
cubic foot OF atmosphere In this meteorological
factor the interest both OF professional sanltarans
and OF the suffering lay has, therefore, been highly
awakened Of aIe II has important bearings health
and comfort which are not yet fully understood
Something Of its immediate operations be gath
cred by comparing ones sensations on a hot day
with the indications of hygrometer Ono form Of
this Instrument is made by placing two good thcr-
mometers side by side. having It's bulb properly
covered with thin cloth, which is kept constantly wet.
Cooled BY evaporation, the mercury will not climb as
high this sdo of the hygrometer as on the other,
the difference depending upon and hence bctraying,
tho precise amount Of vapor in the air. On two
cessve days. for instance the ordinary thermometer,
and consequently tho dry-bulb thermometer Of the
moisture measurcr, might register oO0 IN the shade
But II on one Of these afternoons the bulb ind-
cation was 49, aud on tho next only 74e the weather
in the former would much moro sultry.
In the first instance the humidity would be .51-that
IS, the air would be 81 per cent saturated and would
not readily take up moro moisture. Hence, evapora-
ton from perspring cucle would be very slow and
the consequent refreshment OF that process slight In
the other case, the air would be only AZ per cent
saturated and evaporation. especially If assisted by
light breeze or the use of fan, would proceed rap
Idly and the air would seem to be remarkably bracng
and delicious Ruinous as II IS to linen, the phenome
non Of perspiraon is in wonderfully blessed
provision Of nature but the relief It designed
afford depends upon tho freedom with which It evapo-
and hfs In tur
spongelko atmosphere is already saturated.
In typical summer weather the exposed portions
OF the human body and TO certain extent those that
are only lightly clothed are IN the condition OF a
wet bulb thermometer; and the heat Of which one |
then sensible Is Indicated by that side of hygrom-
eter rather than by the mercury in the dry bulb |
tube In the two instances Just cited an ordinary |
thermometer would have failed to explain the difference
In ones sensations; but the wet bulb INSTRUMENT
showed that afternoon no ar. Could cool the |
observer below $50, while the other the greedy |
absorption OF dampness his skin and In HIS dress
reduced his surface tempera ure TO 74a II will be
readily seen from this that II In two widely sepa-
rated parts Of the country, at the same hour, the
ordinary thermometers registered 11O0 and 9Os in the
shade respectively, material difference In popular
comfort would exist If, in both cases. tho wet bulb
thermometer registered sOa
HOW HUMIDITY AFFECTS MANKIND
1t IS worth noting that high degree Of humidity
Is sometimes safeguard to health ard comfort.
Many delicate maiden has discovered the seaside
that on cool evenings she SIT drafty doorways
near open windows, out from under shelter
without wraps, with perfect impunity whereas at
her inland home such exposure with the same tenn
pcrature-say 7oe-would usually induce a severe
cold. This IS because tho humidity OF the sea air
keeps the temperature Of evaporation" It scien-
tlhcaly called, up at So more and little or no
evaporation actually occurs from her lightly clad
Dcrson In the drler air Of the interior, especially
In anticyclonic' weather. the wet bulb reading
might easily be as low as $50 or $50, with the dry
bulb at 7oS. The urchiH who catches cold from an
unexpected bath with his clothes on does So not as
result Of the wetting but of the drying process
md the risk would be less wet than on a dry
lay, the indications OF ordinary thermometer being
he
When warm, the atmosphere viii hold moro vapor
han when cold At 03', cubic foot Of air needs
vice much water to saturate It at 730, and
light times as much as at 33S. Hence, with
hango Id the actual amount Of moisture present the
relatiye' humidity varies with every huctuaton OF
emperature Usually It Is highest at the coolest
Of the day, Just before dawn and lowest at tho
ottest time, which is about p In New
ork, a very dry summer day, the humidity might
e about .65 30 in the early morning and fall
0 40 or .45 in the afternoon On muggy' day,
he humidity at daybrcak without rain or fog,
hight easily be 50 90 and not get below .65
20 at the elimination Of the days heat With
hf of the wind, however, the temperature and hui
iidty might both rise, fall, a of air much
rier damper than that already observed would =
rObably bo drawn thus TO the place Of observation 4
ometmes. on a hot day sudden rise in humidity t
caused by shower; tho rain drops falling on !
Gated pavement, converted into steam which for
few minutes almost completely saturates the air 4
wENTY DEGREES BETWEEN WET AND DRY
BULBS \
A difference OF eos hetween the wet and dry bulb t
thermometers occurs in New-York half dozen times
year, perhaps At the Central Park Observatory, t
r Daniel Draper has them 25a apart. c.
his IS highly exceptional But there places y
here the extreme dryness OF the air admits Of still II
eater disparity. The Signal Service has readings b
50 apart in Arizona; and occasional difference Of
Early 4o' there and In Central Africa is not ncred
To- In Upper Egypt, porous Jar Of water, set in
70 shade, where the mercury IS well up in the nine u
es becomes cool spring water in short time, >
ON evaporation, and at night falls to the freezing
)int leo Is actually made in similar "
amer In parts OF India. There IS dry re- y
on in tho southwestern part Of the United states.
aching from Western Texas to the Sierra Nevada a.
ID up toward Salt Lake, where army officers often -
Ol their drinking water a hot summers day by :,
nging 1t up in tho shade in canvas bag through v
hch the liquid barely ooze and swinging It to a
ID fro. Even ordinary clothcovered tin canteen =
,tted from the outside, can be used effectively for
Is purpose. In York, the normal humidity
June, IS about 20 for July IL for August, 20
10. But at Forts Grant, Apache and Florence h,
tzona In June IT is "a % and at Winnemucca 4
'vada, about 81 for July and August. No doubt ia
ere many summer days in that region when in IS
e afternoon for two three hours the relative
mdlty is as low IL IA. In the metropolis, a.
summer. it seldom gets below "a 80. even for "
hour
ACTING AS CHECK TO THE ATMOSPHERE.
One interesting effect OF humidity is the check II We
rs on the cooling Of the earth by radiation night be
re in New-York. when general change IS in u.
ogress, the average daily temperature oscillation Nj
out 149 On moist days II IS much less. Rarely he
the drest day does It exceed oO'. But in Central