KXI'IUMTION TO POINT HAKKOW, ALASKA. 



Tin- mean values of // by the two instruments and methods agree. \vcll, and t!ie monthly value/, 

 may therefore advantageously lie united as shown In-low: 



Mean II from L'l mouths of observation, 1.93C, answering to the epoch October (middle), 1882. 

 Annual increase approximately O.OOG 



The following table contains the resulting monthly values i'or the horizontal, the vertical and 

 the total intensity, the last t\vo quantities computed from the relations, V=H tan H and F =11 sec 0; 



In order to facilitate comparisons of similar quantities at other stations, using different units 

 of measure, the values of H, V, F at Uglaamie are given in the table expressed in the three differ- 

 ent systems of units at present in use, viz: the English system in foot, grain and second units : 

 the Gaussian system in millimeter, milligramme, second units; and the British Association or tho 

 C. G. S. system in centimeter, gramme, second units, or dynes. 



Bcnullliiff horizontal, vertical ami total magnetic force at I'ylaamic. 



To an annual change of rfW in the dip It and an annual change >'// in the horizontal component 

 of the force H there correspond annual changes of fiT and rt'F in the vertical component 1" and in 

 the total force /', respectively, viz : 



.> l' = tan .W//+// sec' J H<V> $F=w. rf//+7/ sin H sec- MH 



hence for fS=_l'.ii and ,)'// = + ().0(Mi, we find <JK= +0.010 an<l fil<'= +0.010 in English units, and 

 in dynes with rf/f= + .OOI>L',s, fi r=.OOOKi and fiI-'=.()QQW 



