Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1907-08-06

things being equal, there Is more cvap-
grafton the warmer, the drer, and the
less quiet the air The hotter the air,
the greater its capacity for water vapor.
the drier the air. the more water can
still be evaporated into 1t; the more
wind, the greater the opportunity for
evaporation Into Il: the more wind, the
greater the opportunity for evaporation
into the fresh supply of air which is
constantly brought 10 the body. IL
the air be completely saturated at the
body temperature, there can be no
evaporation: but II the air be saturated
below the body temperature, the body
warns the air nearest It; In so doing
the capicty of the air for water vapor
is Increased and evaporation may then
begin again. Even II the temperature
of the air be 9S.6 deg, unless the air he
saturated, the body can cool by evpp
Grafton. 1t has been shown that when
the air is very dry human beings can
endure extraordinarily high tempera-
ture, as In the case of man who
stayed twenty minutes In dry air at
212 deg. Hot dry air in motion is
much cooler than hot dry air at rest,
and hot moist air is oppressive because
there is little opportunity for cvapora-
ton. The moist heat felt during a
voyage across the Red Sea In August
or September. with an air temperature
OF 30 deg, is much more oppressive
than is the heat in the upper provinces
Of India during the blowing of the
hot Winds" which are dry, when the
temperature Is 112 deg. and 11S deg.
The excessive dryness of these winds
Is made use of to keep the air of dwell
ings cooler by means of wet 'tatties"
hung over doors and windows. The
more moist the air and the nearer it's
temperature to that of the body, the
less difference does wind make Dry
air is In many respects an advantage
at all seasons; in winter, because II
makes the loss of heat by conduction
less, and in summer, because II IN
creases the loss of heat by evaporation.
HUMIDITY AND TEMPERATURES.
Evidently. too. conduction enters
into this question, for when the air Is
moist. evaporation is lessencd, but
conduction (unless the air be MT the
body temperature) is increased. On
the whole. oonduction is at maxi
mum in winter. and evaporation In
summer. The very dry air of our fur
nace-heated houses in winter must be
kept at a high temperature IL we
wish to be comfortable In IT, We les
sen the loss of heat from the body
by conduction when we raise the tenn
perature. but the loss by evaporation
must be very great, because Of the
drvness of the air If our houses
were provided with more moist heat
we could be comfortable indoors with
considerably lower temperature. he
cause evaporation would be so much
decreased. This has been experiment.
ally determined by DR.. Henry ].
Barnes of Boston, who found that
when the air in his office had rela-
tive humidity of 81 per cent the tenn
perature had to be 20 or II degrees,
but when. by means of "humidiiier,"
which evaporated Az quarters of
water daily, he had brought the air
to relative humidity Of SO per cent
temperature of 65 degrees was com
Portable. The temperatures In our
houses are comfortable ut about 70
degrees, because the air is calm. If
the air were in motion we should be
uncomfortably cool, because of the in
creased evaporation.
The temperature which we feel does
not depend solely on the temperature,
the moisture, and the movement of the
air. 1t is also influenced by the physic-
al condition in which the body finds
itself. for the body is not a passive OBJ
iect. When In health II adjusts itself
to surrounding conditions by its own
action. At low temperatures 1t seeks
to check the loss of heat from its sur
face by contracting the pores, keeping
tho skin dry. and diminishing the
amount of heat near the surface Of
the body. At high temperature, on
the other hand. the pores are opened,
perspiration is abundant. and the
skin is cooled by evaporation. Fur
thermore, the relations of the body
to the meteorological conditions of the
atmosphere are affected to n very
marked degree by the clothing. Many
interesting experimental studies have
shown that the differences between
the temperature on the surface Of the
clothing and the air temperature de-
crease with an increasing num-
Der of articles of clothing be-
tween the skin and the outside air. The
successive air strata between the dit
ferent layers OF clothing serve to modi-
fy the effect Of the temperature and
humidity of the air Thus clothing.
whose thickness, weight and texture
may be varied at will keeps the body