ON COMPARING AND BEDUCING MAGNETIC OBSERVATIONS. 



95- 



of Beceviher, 1875. Hoitrly Abstract of Tabulations (in Inches) of 

 Force Magnetograph. 



1875. Hourly Determinations of 2^-day Means of each Sour. 

 Magnetograph. 



The actual operation is to add this excess to the 29-day sum of the pre- 

 ceding day, and enter the result as the 29-day sum of the day of the 

 entries. The 29-day sums are divided by 29 by means of a table of 

 products of 29 into all the integers from 1 to 999, and the quotients 

 are entered below as the 29-day means. The integer 1 in each number 

 of Table A is thrown out of account in the construction of Table B,. 

 and this is kept in mind in taking the differences of Table C. 



