BETWEEN SUN-SPOT FREQUENCY AND TERRESTRIAL MAGNETISM. 

 TABLE XVI. Katharinenburg (Units 1' in D, ly in H and V). 



173 



Batavia (6 11' S. lat, 106 49' E. long.). 



25. Prior to the introduction of electric tramways in 189!) the magnetic results 

 fit Batavia Observatory were treated with great completeness in the annual Batavia 

 1 Magnetical and Meteorological Observations.' 



Up to the end of 1900 the I) and H results seem to have suffered comparatively 

 little, but the V results even then were too disturbed for publication. 



The Batavia magnetic records go back to 1882, but are incomplete until 1884. 

 Inspection of the vertical -force data for 1884 and 1885 created some misgivings, 

 which gathered force from an editorial statement that the scale value in that element 

 was at first very variable and remained so until a new magnet was introduced. 



After considering all the circumstances, I decided to confine myself to the results 

 for the 12 years 1887 to 1898, coming down to the latest time at which all the 

 elements were free from electric-tram effects. This period has the advantage of 

 supplying a sun-spot minimum group of years 1887 to 1890 equal in length to the 

 sun-spot maximum group 1892 to 1895. 



The Batavia tables give not merely the hourly values, but also the sum of the 

 24 differences from the mean, in the monthly diurnal inequalities. 



In (A) I found the sum of the 24 differences in D and H to show the sun-spot 

 connection even more prominently than the ranges. Accordingly I decided to use 

 the sum of the 24 differences at Batavia, in preference to the ranges, when dealing 

 with the diurnal inequalities for the individual months, and to employ the sum of 

 the 24 differences as well as the ranges when dealing with the mean diurnal 

 inequalities for the year. 



26. Before giving the results, I would draw attention to a feature wherein Batavia 



