200 



RE POUT ON 



The following table shows, for each compass, the maximum change, Ar\ in its 

 deviation, which occurred on any single point, together with the azimuth at which, 

 and the places between which that change occurred. 



In order to show the difference between the values of the deviation computed 

 from observations made at a single station, and those computed from all the obser- 

 vations of the cruise, or, in other words, the difference between the theory and the 

 observations, let ^ be the deviation of a compass on any point, , at a given station, 

 as computed from values of A B^ O lt Dj, E^ derived from all the observations of 

 that compass made during the cruise; and also let b' be the deviation of the same 

 compass, on the same point, at the same station, as computed from values of A } , 

 BI, (7,, Z>,, EI, derived from observations of that compass made on each of the 

 thirty-two points at the station in question. Then the following table shows, for 

 each compass, the maximum value attained by ^ <$' during the cruise, together 

 with the point on which, and the station at which, that maximum occurred. 



