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SCIENCE 



[N. S. Vol. XXXIV. No. 877 



Declination. — rrom measures on the collimators 

 and from a discussion of the observed declinations 

 in different positions of the instrument the follow- 

 ing corrections were determined. Some confirma- 

 tory results from short series of direct and re- 

 flected observation taken in 1909 are also tab- 

 ulated. 



Dn is a constant correction to reduce direct 

 observations of north stars to the mean of direct 



The probable error of a single observation is 

 reduced from 0".62 to 0".34 for circle A and from 

 0".58 to 0".44 for circle B. 



and reflected, and Vs is a similar correction for 

 south stars. 



By the application of the corrections due to the 

 flexures, etc., as determined from the observations, 

 the following improvements are made in the mean 

 differences taken without regard to sign: 



All of the cosine flexures considered above are 

 completely eliminated from the mean of an equal 

 number of clamp east and clamp west observations. 

 The following table gives comparisons with the 

 declinations of Boss, and the reduction from Boss 

 to Newcomb. The direct observations were re- 



