your shoes. If both are right, you are right.

"The chief uses of clothing are to help the body maintain its normal
temperature and to protect it from sun, frost, wind, rain and injuries.
_To help_, mind you--the body must be allowed to do its share.

"Perspiration is the heat-regulating mechanism of the body. Clothing
should hinder its passage from the skin as little as possible. For this
reason one's garments should be _permeable_ to air. The body is cooled
by rapid evaporation, on the familiar principle of a tropical water bag
that is porous enough to let some of the water exude. So the best summer
clothing is that which permits free evaporation--and this means all
over, from head to heel. In winter it is just the same, there should be
free passage for bodily moisture through the underclothes, but extra
layers or thickness of outer clothing are needed to hold in the bodily
heat and to protect one against wind; even so all the garments should be
permeable to air. * * *"

"Underclothing, for any season, should be loosely woven, so as to hold
air and take up moisture from the body. The air confined in the
interspaces is a non-conductor, and so helps to prevent sudden chilling
on the one hand, and over-heating on the other. A loose texture absorbs
perspiration but does not hold it--the moisture is free to pass on to
and through the outer garments. In town we may indure close woven
underwear in summer, if thin enough, because we exercise little and can
bathe and change frequently. In the woods we would have to change four
times a day to keep * * * as dry.

"_Wool versus Cotton_--Permeability also depends upon material. Ordinary
cotton and linen goods do not permit rapid evaporation. They absorb
moisture from the skin, but hold it up to the limit of saturation. Then,
when they can hold no more, they are clammy, and the sweat can only
escape by running down one's skin.

"After hard exertion in such garments, if you sit down to rest, or meet
a sudden keen wind, as in topping a ridge, you are likely to get a
chill--and the next thing is a 'bad cold' or lumbago, rheumatism, or
something worse.

"Wool, on the contrary is permeable. That is why (if of suitable weight
and loose weave) it is both cooler in summer and warmer in winter than
cloth made of vegetable fibre. 'One wraps himself in a woolen blanket to
keep warm--to keep the heat _in_. He wraps ice in a blanket to keep it
from melting--to keep the heat _out_.' In ot