APPENDIX E 271 



These considerations lead to the conclusion that humidification of 

 the air in houses should be universal during the winter. If the air has 

 a humidity of 60 per cent and a temperature of 64*°, that is ample for 

 both health and comfort. Such air can cool down to 55° at night with- 

 out danger of depositing moisture except on the windows. Even if the 

 humidity is no more than 50 per cent, our health and comfort will be 

 greatly increased. 



If we would have the very best health, however, we must remember 

 that it is not wise to preserve a uniform temperature and humid- 

 ity. The right average must be secured by varying the temperature 

 first one way and then the other. The air in the ideal house should 

 fluctuate back and forth from about 60° to 68° at irregular intervals. 

 Such fluctuations may not seem pleasant at first if begun in the middle 

 of the winter after people have become softened by dry air and uniform 

 temperature. So long as the windows are kept open, however, they 

 prevail naturally in the fall at the very time when people's health is 

 best. If the conditions of those fall days, with their optimum temper- 

 ature, their comparatively high humidity, and their variability could 

 prevail all winter, it seems probable that the appalling increase in our 

 winter deathrate would be much diminished. 



Another important consideration is the degree of movement of the 

 air. In many houses the air moves so little that the upper part of a 

 [ room may have a temperature of 75° while on the floor the thermometer 

 I records only 65°. Such a condition is of course undesirable. It can 

 I be avoided only by a proper system of ventilation. 



Having seen the nature of the atmospheric conditions most favor- 

 <i able to health, the next step is to secure them. The first and greatest 

 i requisite, as we have seen, is proper temperature. Today 70° is the 

 ,, standard indoor temperature, although wise people see that 68° would 

 be better. Our study of health shows that an average of 64° is appar- 

 ently high enough. If this were the only element in the problem we 

 could simply reduce our coal consumption until our rooms averaged 

 i 64° instead of 70° during the hours when we are not sleeping. That 

 I in itself, if we may judge from the experience of the New York schools, 

 I would decrease the number of colds by nearly half. Such a result 

 I would be due not merely to the more favorable temperature, but also 



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