rvP.M KICIKNTS TO APPLY TO Mi:\\ UKMamoNS FOR 



\VUmmNX l\ ItAKOMKTKK AM) TKNPKKATl 'UK. 



Any true refraction either In zenith or polar distance tabulated refraction X coef- 

 ficient for barometric pressure X coefficient for temperature. 



The differences between the true and the tabulated refractions are generally snuill 

 nii'l K'-nerally negligible excepting for the combined effect of low apparent altitude 

 of observation with high elevation above sea level or extremes of temperature. 



4147910 14 



