NO. 6 BODY RADIATION ALDRICH 21 



temperatures we can compute from the Stefan formula the average 

 radiation per sq. cm. per minute from the body. It results as follows : 



March 31, from thermoelement, .1003 cal., from melikeron, .1109 cal. 

 April I, from thermoelement, .0432 cal., from melikeron, .0673 cal. 



Thus the body actually radiated in the order of twice as much when 

 the walls were at 15° as when the walls were at 26°. The best work 

 in basal metabolism indicates that an individual's metabolism remains 

 practically unchanged through this range of room temperature. A 

 very considerable readjustment, perhaps of water vapor loss, must 

 take place to compensate for the large change in radiation. 



Let us compare the two series of experiments on human subjects 

 recorded in tables B and E. Each series included 10 individual sub- 

 jects, composed of adults and children of school age, of both sexes and 

 all normally clothed. The first series was performed in midwinter, 

 the second series in midsummer. During the first, the mean relative 

 humidity was 43% and during the second 62%. In each series de- 

 terminations were made on each subject of the total loss of heat by 

 radiation in still air. The second of the two series deserves greater 

 weight for two reasons : 



(i) Cloth walls were used and the mean wall temperature deter- 

 mined from actual measurements with the thermoelement. 



(2) A greater number of skin and clothing temperatures were 

 measured since only the thermoelement was used. 



In the first series the subject radiated to the walls, windows, and 

 furniture of the room. Their mean temperature was estimated from 

 the room temperature, after a study, on a typical day, of the relation- 

 ship between the room temperature and that of the walls, windows, 

 and furniture. From this study it was concluded that the mean wall 

 temperature was probably ?5 below room temperature. Ibis arbi- 

 trary correction was adopted for all the preliminary 10 subjects and 

 also for the preliminary calorimeter experiments (see table C). It is 

 remarked on page 17 under (2) that the estimated wall temperatures 

 in the table C data are probably too low. The reason for this can 

 be seen from the fact that the table C data were obtained' in the 

 spring, whereas the table B data were taken in midwinter. The mean 

 outside temperature was ii?o for table C, and 3°5 for table B. It is 

 evident that with a warmer temperature outside, the °5 difiference 

 between room and wall temperature was too great. On the other 

 hand, on examining the data of the typical day from which the arbi- 

 trary °5 correction was determined, I find that the outside tempera- 

 ture was 2° and that the mean wall temperature was in reality i°o 

 below room temperature. The arbitrary correction was made "5 



