72 SEVENTEENTH REPORT. 



laws of chance, assuming- that the start was made on the second or 

 tlie third step. The "skewness" of the curve (i. e., the fact that the 

 mode is not exactly at the center of the series) may be due to the 

 fact that tlie platform furnished a landmark at one end of the 

 series. 



I am indebted to Professor Goddard for aid in making the obser- 

 Aations upon which this account is based, and to Mr. C. C. Edwards 

 for jihotographing the nests. 



