172 



PROCEEDINGS OF THE AMERICAN ACADEMY 



The probable errors (1) and (2) do not agree very well, owing to 

 the small number of observations ; but those denoted by (2) are the 

 larger, upon the whole, owing to errors constant either for all the ob- 

 sei-vations of a night, or upon a pair of stars. The three results wUl 

 be thus : — 



Class (a) 

 „ (7) 



38°50'41//61 

 41.41 

 41.46 



Probable Error. 



(1) 



J-(y'069 

 -t- 0.134 

 J- 0. 096 



-to'aoi 



i 0. 099 

 ± 0. 126 



I think no considerable uncertainty will be left if the stars of Class 

 (|S) have a weight of | each, and those of Class (j') \ each. This will 

 give the total probable error for weight 1, a thoroughly good pair suf- 

 ficiently observed ; as, — 



and the final latitude 



88°59'41'/47 ±0^067 



including errors of all kinds. 



The latitude is manifestly determined with all the precision neces- 

 sary for an arc of the meridian ; the instrument being of the largest 

 class, the observer excellent, and the star-places the result of a careful 

 investigation. 



