114 ANNUAL REPORT SMITHSONIAN INSTITUTION, 192 8 



one-third less than the radiation loss in still air and normal room 

 temperatures. 



(4) Increasing air motion rapidly decreases the percentage radia- 

 tion loss and increases the convectional. With the vertical calo- 

 rimeter : 



Per cent 

 Air motion : radiation loss 



60 



75 feet per minute 41 



130 feet per minute 35 



190 feet per minute 25 



(5) Total body radiation similarly decreases with air motion: 



Air motion : Radiation loss (mean for 10 subjects) 



50 feet ijer minute 30. 7 large cal. per sq. m. per tiour. 



50 to 100 feet per minute 29. 3 large cal. per sq. m. per hour. 



100 to 150 feet per minute 25. 7 large cal. per sq. m. per hour. 



180 to 250 feet per minute 23. 2 large cal. per sq. m. per hour. 



(6) Increase in room temperature (which also means increase in 



wall temperature) produces a progressive lowering of radiation loss. 



mi X- Radiation loss -, -ii, • ^ ^ ^a 



The ratio ^^ -, r-i — r- decreases with increase oi room and 



Basal metabolism 



wall temperature : 



Radiation loss 



Basal metabolism 



Table L. 

 Table J. 



0.80 (mean of 10 subjects). 

 0.75 (mean of 10 subjects). 

 0.84 (mean of 3 subjects). 

 0.74 (mean of 4 subjects). 

 0.66 (mean of 3 subjects). 



(7) Keeping room and wall temperatures unchanged, the tempera- 

 ture of the skin and clothing decreases with increasing air motion, 

 the decrease being greatest on the side facing the wind and about 

 one-half as great on the side away from the wind. The clothing 

 temperature drop on the side toward the wind is about one-third 

 greater than the corresponding skin temperature drop. Summary of 

 10 subjects : 



Air motion (feet per minute) 



^^'° ^d^p^""**^"^^ • Clothing temperature drop 



Away 

 from 

 wind 



Toward 

 wind 



Away 

 from 

 wind 



Toward 

 wind 



Perpen- 

 dicular to 

 wind 



OtolOO... 

 100 to 250. 



C. 

 -°.4 



-°.7 



C. 



-".8 



-r.2 



c. 



-1°.3 



-°.6 

 -".5 



