1878.] 



Magnetic Declination at Prague. 



393 



5. Tlie results of Tables III and IV are exhibited in Diagram I 

 above, in which figs. 1 and 3 represent sun-spot values, and figs. 2 and 

 4 Prague declination-ranges. From these figures it will be seen that 

 a number of points in the sun-spot curves may be fairly identified as 

 corresponding to certain points in the declination-range curve, but 

 that the latter invariably lag behind the former in time. It ought, 

 however, to be borne in mind that here the materials for comparison 

 are not quite of the same order of completeness as in the case of Kew 

 and Trevandrum. 



The lagging behind may be well seen by comparing together the 

 epochs of maximum and minimum sun-spot frequency with the corres- 

 ponding epochs of declination maximum and minimum range. We 

 thus obtain the following result : — 



Table V. In which the Epochs of Maximum and Minimum Sun- Spots 

 are Compared with those of Declination-Range. 



Solar min., June 15, 1843. . .Prague, dec-range, min., Feb. 28, 1844. 

 Solar max., Dec. 15, 1847. . .Prague, dec. -range, point 7, max., March 



31, 1848. 



o ■> • cj l i k iokc / Prague, dec. -range, min., Mar. 31, 1856. 

 Solar mm., Sept. 15, 1855 < s ' & ' . ' ' 



I Irev., dec-range, mm., Feb. 15, 1856. 



Q n -vr -ik intra /Kew, dec-range, max., April 15, 1860. 



Solar max., Nov. 15, 1859 < _ & ' ' 



I lrev., dec-range, max., May 15, I860. 



Solar min., Mar. 15, 1867. . .Kew, dec-range, min., August 15, 1867. 



I have thus examined the most trustworthy sun-spot values and 

 declination-ranges, and it may, I think, be fairly concluded that there 

 is an intimate relation between the two phenomena, but that the 

 points of the sun-spot ranges precede those of the declination-ranges 

 in respect of time. 



Variations wTiicli seem to depend on Planetary Configurations. 



6. The Prague proportional values herein given cannot be regarded 

 as equally good for the purpose of investigating these periods with 

 those derived from Kew or Trevandrum. In the Prague series we have 

 only one value for each month, whereas in the Kew or Trevandrum 

 series we have one value for each week. Inasmuch, however, as the 

 Prague series is longer than either of the others we may, perhaps, 

 regard it as of equal value for the purpose now in hand with the Kew 

 series, while the Trevandrum series, on account of its comparatively 

 short duration, can hardly be regarded as possessing more than half 

 the weight of either of the others. If we treat the Prague observa- 

 tions in the manner in which the Kew observations were treated (Proc. 

 Roy. Soc, March 22nd, 1877), we obtain the following result : — 



