MAGNETIC OBSERVATIONS. 



181 



The observations made at stations where the deviations had been determined on 

 all of the thirty-two points were first discussed. For that purpose the values of 

 the coefficients J. H JB,, C^ J5,, E^ for each compass, at each station, were computed 

 from the deviations on the true magnetic points by means of the equations given 

 on pages 126 to 128. A specimen of the form employed in making these com- 

 putations is appended. It sufficiently explains itself. 



ADMIRALTY STANDARD COMPASS. COMPUTATION OF COEFFICIENTS B, AND C,, FROM DEVIATIONS 



, OBSERVED ON 32 POINTS, ON THE U. S. IRON CLAD MONADNOCK. 



Bahia, December 30, 1865. 



N. B. Easterly deviations are to be entered in this table with the sign +; Westerly deviations with the sign . 



