LENA KEYS TO GUADIANA BAY 213 



and shirts of very heavy white wool which they 

 found preferable to any sort of rubber or oil-skin 

 protection. One would reasonably suppose that 

 such a covering would be intolerably hot in the 

 temperature of 76 (about the day's average). 

 There is much that is peculiar about the relation 

 of the body to air temperature in the tropics. 

 Very slight changes of temperature, especially a 

 drop of four or five degrees, are keenly felt. On a 

 bright sunny day with a temperature of, say 78 , 

 one dresses in very thin clothes and seeks the shade. 

 If a passing shower depresses the glass to 74 , one 

 may find a wrap comfortable. At 69°, one may 

 positively suffer with cold, especially if the air is 

 damp, and a temperature of 6o° fairly shrivels 

 up a community. Apparently a residence in the 

 tropics, where temperature changes are rela- 

 tively slight, deprives the skin of its adaptability 

 acquired in colder climates. Humidity in the air, 

 whether north or south, greatly increases the effect 

 of temperature upon the body, but this is even 

 more felt in the tropics. In New York, for in- 

 stance, a temperature of 76 , with a high degree 

 of humidity, would be hot and uncomfortable. 

 Here it gives a feeling of cold. The dividing line 



