84 



PROCEEDINGS OF THE AMERICAN ACADEMY 



character of the atmospheric conditions under which the observa- 

 tions were made. Arranging the resuUs according to the character of 

 the seeing, we have : 



TABLE VIII. — Seeing Fair to Good. 



Combining by weights proportional to the number of observations, 

 we have : 



TABLE IX. 



From the observations made under favorable conditions, we have 

 for the distance unity : 



D for i = 90° 



16".01 



D for i = 10° . . . . 45° 



16".24 



There is a general tendency of the observations to indicate a lesser 

 value for the equatorial diameter, but the method of obtaining this 

 quantity by direct transits over a vertical line is not a very reliable one. 

 The apparent difference, therefore, between the diameter determined 

 at different angles of inclination, is probably fictitious rather than real. 



In order to determine the difference in the amount of the irradiation 



