AT STATIONS ON THE COASTS OF THE BRITISH ISLES, 1907. 



245 



Tearf^ifff 

 only. 



lOy 



1889 90 91 HI 93 94 95 96 97 is S9 1300 01 02 03 0* 05 06 07 "08 







Fit;. ''. Curve of mean annual increase of Horizontal Force ;it Kew 



O 



(derived from quinquennial means). 



Fig. 4. Curve of mean annual decrease of Inclination at Kew 

 (derived from quinquennial means). 



Comparison of Declination Value* Observed at tivit tvit/t tlivse on Shore. 



To compare the values of Declination at sea with those observed on shore, 

 H.M. ships "Research" (Captain M. H. SMYTH, R.N.) and "Triton" (Captain 

 W. PUDSEY-DAWSON, RN.) were instructed to obtain the values of the Declination 

 by "swinging ship" in deep water in the vicinity of the shore stations. 



The vessels were swung turning to starboard and to port and a mean of the results 

 accepted as the value of the Declination. 



These results have not been corrected for diurnal variation, but allowance has been 

 made for secular change to reduce them to epoch 1st January, 1907. 



An allowance in each case has been made for the difference of position from shore 

 station, such allowance having been derived from a consideration of the values shown 

 by the mean lines of equal Declination on the Admiralty charts of equal Declination. 



The results, which cannot be considered to a closer degree of accuracy than 10', 

 are given in Table IV. 



