"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 other words, wool is the best material to maintain an equable normal temperature."
Camp Site
"The essentials of a good camp site are these:
1. Pure water.
2. Wood that burns well. In cold weather there should be either an abundance of sound down wood, or some standing hard wood trees that are not too big for easy felling.