138 



Absteacts foe the Magnetic Declination. 



TABLE IV. — The Yearly Decrease of "Westerly Declination, as Deduced from the Four Daily Observations in 



the Five Months of 1841 and 1842. 



Month. 



20h. 



2311. 



21-. 



5t. 



Mean of the 

 Four Hours. 



July 



1-29 



2-09 



1-06 



6-80 



1-31 



August 



9-50 



7-59 



9-02 



9-29 



8-85 



September 



3-55 



2-35 



4-29 



5-31 



3-87 



October 



3-31 



2-78 



115 



2-20 



2-36 



November 



3-97 



3-52 



3-81 



4-62 



3-98 



Means 



4-32 



3-66 



3-87 



4-44 



4-07 



If the results for July and August be rejected, the mean of the other three months will be 3'"40. 



TABLE V. — The Extreme Readings of the Declinometer for each Month from the Four Daily Observations. 









North End of JSIagnet Farthest 







Month. 





E 







W. 



Range. 



Gottingen 

 Mean Time. 



Declination. 



Gottingen 

 Mean Mime. 



Declination. 



1841. 



d. h. 



m. 



o , 



d. h. 



m. 



. - 



' 



July 



12 20 







25 21-80 



15 2 







25 41-29 



19-49 



August 



11 20 







25 26-81 



23 20 







25 50-30 



23-49 



September 



8 20 







25 22-64 



25 2 







25 53-14 



30-50 



October 



12 20 







25 21-67 



24 20 







25 45-59 



23-92 



November 



24 20 







25 25-58 



5 2 







25 49-77 



24-19 



1842. 

















January 



27 20 







25 25-30 



29 2 







25 33-31 



8-01 



February 



17 5 







25 18-15 



18 2 







25 40-52 



22-37 



March 



9 5 







25 21-23 



30 2 







25 42-80 



21-57 



April 



24 20 







25 20-85 



14 20 







25 52-33 



31-48 



May 



18 20 







25 21-38 



16 5 







25 49-71 



28-33 



June 



2 20 







25 19-92 



10 2 







25 40-63 



20-71 



July 



20 20 







25 20-93 



2 2 







25 38-01 



17-08 



August 



16 20 







25 20-15 



' 4 23 







25 38-92 



18-77 



September 



25 20 







25 22-20 



22 2 







25 40-23 



18-03 



October 



17 5 







25 16-43 



8 2 







25 36-80 



20-37 



November 



11 5 







25 22-44 



10 2 







25 38-37 



15-93 



December 



8 5 







25 18-83 



30 2 







25 31-76 



12-93 



The range of the five months of 1841 from the Daily Observations is 31'-5. The Westerly Declination being 

 least in October, 8'"4 below the mean of the month ; and greatest in September, being 20'- 9 above the mean of 

 the month. 



The range for 1842 is 35'-9. The Westerly Declination being least in October, 10''9 below the mean of 

 the month ; and greatest in April, being 18'- 9 above the mean of the month. 



I 



