ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 



325 



Table I. — Numher of times the declination-deviations of different size occurred 

 at the various hours of the day. 



Batavia Local Time 



Total number for each six 

 hours 



O'-l' 



l'-2' 



2'-3' 



3'-4' 



■i'-5' 



5'-«' 



6'-7' 



7'-8' 



8'-9' 



9'-10'i 



lO'-Il'i 



ll'-12'| 



12'-13'| 



13'-U' 



14'-15'| 



15'-16'| 



16'-17'| 



17'-18'| 



18'-19'| 



19'-20'| 



20'-2l'j 



21'-22'| 



22'-23'i 



23'-24'| 



24'-25' 



25' + 



irli 



835 



1798 



3333 



1072 



706 



468 



292 



156 



111 



63 



41 



24 



21 



20 



6 



8 



9 



3 



6 



6 



5 



4 



1 







1 



10 



Exact 

 time of 



Pawlowsk Time of Gottingen. 



j Number for eacli six hours of 

 gixe j the ne};'ative (— ) and positive 

 ( + ) disturbances 



0-2'- 



3'-4' 



4'-6' 



6'-8' 



8'-10' 



10'-12'- 



12'-15'- 



15'-20' 



20' + 



The whole number of disturbances, when 

 they are less than 4', is greater about noon ; 

 and, on the contrai-y, the disturbances which 

 are larger than 5' are more frequent about 

 midnight. 



The easterly and westerly disturbances 

 are in the full table of Dr. van der Stok, 

 ■vii. p. 188, nearly equal in number on the 

 whole, though the ratio differs for the dis- 

 turbances of larger and smaller size. 



Therefore I think myself authorised to 

 give for this place also the exact hour of 

 the max. and min. for the sum of both 

 <+ and — ) disturbances, and find the hour 

 of the max. for disturbances less than 4' 

 he/ore noon, and the hour for disturbances 

 greater than 4' later in the afternoon, about 

 at 20 o'clock. 



Midnight = hour ; noon = 12 hours. 



The negative disturbances (as given 

 by Mr. Miiller by the method of Prof. 

 Wild) wers found to be more numer- 

 ous than the positive ones before 16 

 o'clock, especially tlie more so the 

 larger they are, but on the contrary 

 less frequent after that time of the 

 day, 10-3. 



It appears to be a consequence of 

 some fault in the methods of Prof. 

 Wild, and it would have been useless 

 and not true to give them separately 

 for each hour. 



