194 



REPORT ON 



directly from the table; while the coefficients 53 and S were obtained by means 

 of the formulae 



H 

 1 



A 



H 



t 

 H 



where is the true magnetic dip; -Z^the earth's magnetic horizontal force, expressed 

 in English units, namely, in feet, grains, and seconds; and t the time in days, 

 counted from November 1st, 1865. The results, expressed in parts of radius, are 

 as follows: 



COEFFICIENTS OF THE DEVIATIONS OF THE ADMIRALTY STANDARD COMPASS. 



COEFFICIENTS OF THE DEVIATIONS OF THE AFTER BINNACLE COMPASS. 



COEFFICIENTS OF THE DEVIATIONS OF THE AFTER RITCHIE COMPASS. 



