CHAPTER XXI 



CLOTHING AS A PROTECTION TO JACK'S HOUSE 



THE normal temperature of our bodies, ninety-eight 

 and six-tenths degrees, is almost always higher than 

 that of the surrounding air. On this account, the 

 heat made by the union of oxygen and bodily tissues 

 would generally escape too quickly, if there were no 

 outside covering to prevent. The fur of animals and 

 the feathers of birds sufficiently regulate the passing 

 of their bodily heat. Man, having only a thin, delicate 

 skin for an outside covering, must conserve the warmth 

 produced by combustion in his body by means of 

 clothing. 



People often speak of wearing apparel as warm or 

 cold, but clothing does not give warmth of itself. Its 

 power to keep us warm depends entirely upon how 

 slowly or how rapidly it allows the heat generated in 

 our bodies to pass away. Feathers and fur are very 

 poor conductors of heat, and make very warm clothing. 

 Dry air not in motion is also a very poor heat conductor. 

 Consequently cloth having numerous air spaces makes 

 warm clothing, while fabrics so closely woven as to 

 contain but a small number of air spaces are better 



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