THE LAND OF FOOTPRINTS 



cally constant whatever the temperature of the air 

 and is dangerous even on a cloudy day, when the 

 heat waves are effectually screened off, but when the 

 actinic rays are as active as ever. For this reason 

 the protection of helmet and spine pad should never 

 be omitted, no matter what the condition of the 

 weather, between nine o'clock and four. A very 

 brief exposure is likely to prove fatal. It should be 

 added that some people stand these actinic rays 

 better than others. 



Such being the case, mere temperature tables 

 could have little interest to the general reader. I 

 append a few statistics, selected from many, and il- 

 lustrative of the different conditions. 



408 



I 



