AIR DRAINAGE AS AFFECTING ACCLIMATIZATION. 35 



thermometer was exactly on the flowing line, it would give it, but really 

 there is not enough of it. There would be radiation enough from the 

 ground so perhaps you would not get any. 



Mr. Muiison — Has any downflowing current been discovered near 

 the ground ? 



Dr. Ma.cDougal — I don't know how we are going to escape it. It 

 has been a matter of observation with me. I am using the mountain in 

 my illustration, because here we have a thing that is most accentuated. 

 Take this cafion situation. The wind there becomes so strong as to 

 become actually unpleasant, and in the autumn or in the spring, much 

 of the time we find the temperature is too uncertain for comfort. I find 

 the Indian, and next to the Indian, the prospector, and the man who is 

 out of doors, avoids the.^e cafions and keeps on the cooler ridges where he 

 is not bothered at all. This movement is reversed during the day. You 

 have the upflow during the day and the downflow during the night. 



Dr. Gager — May I say a word in response to a request for a specific 

 instance of the observation of such an occurrence? The matter has 

 been very thoroughly worked out on Cayuga Lake, by the observations 

 of .Cornell University, and the result has been published as to this down- 

 flow of cold air. 



A recess was here taken until two in the afternoon. 



First Session — Afterxoox. 



The President — The time for our Afternoon Session has arrived. 

 We will have a paper on "The Real Factors in Acclimatization," by Frede- 

 ric E. Clements, University of Nebraska. In the absence of Mr. Clements, 

 Dr. MacDougal will read the paper. 



