290 



Dr. W. J. S. Lockyer. 



The period of this retardation can be deduced by taking the 

 interval between the times of maxima or minima of this secular 

 variation curve. By considering the minima, i.e., from 1833*9 to 

 1867*2, we have a period of 33*3 years, and if we take the maxima 



Fia. 2. 



1800 



10 



SUNSPOT 



CURVE. 



(YEARLY MEANS.) 



SUNSPOT 



CURVE. 



(ORDINATES MIN-MAXJ 

 WOLF. j 



MAGNETIC 

 CURVE. 



(ORDINATES MIN-MAXJ 

 ELLIS. so 



TOTAL SUNSPOT IQQ 

 AREAS. 



[PER PERIODJ 

 (S. P. O. REDUCTIONS /2 ° 

 CURVE INVERTED. 



■WO 



bruckner's 



CLIMATE 

 VARIATIONS. 



RAINFALL. . /Q 

 /. REGULARE QESIETE.I. 



«3. WHOLE EARTH 



at 1843*5 and 1879*0 we obtain 35*5 years. The mean of these two 

 values gives a period of 34*4 years. 



The Magnetic Curves. Minimum to Maximum. 



Mr. Ellis's values for the dates of the magnetic epochs were investi- 

 gated in exactly the same way as the sunspot epochs were examined. 



