46 H. I. JENSEN. 



The total spotted area for the period 1879.80 to 1890.2 

 was 78,253 in millioirths of the sun's disc, as compared 

 with 96,734 for the period 1890.2 to 1900.0, and 126,188 for 

 the period 1867.2 to 1879. 1 We find the sunspot period 

 between 1884 and 1889 divided as follows : — a maximum 

 lasting from 1884 till June 1886, and a minimum from 

 October 1886, culminating in June 1889. 2 



Now on looking at the earthquake records for these years 

 we find great volcanic activity between 1876 and 1881, a 

 marked falling off in 1882, a most abnormal increase in 

 1883, and almost total absence during 1884-5, and a renewed 

 activity in 1886, comprising the Tarawera eruption in 1886 

 and the Bandaisan eruption in 1888. Thus for this period 

 the volcanic outbursts seem to have corresponded pretty 

 closely with extinctions of sunspots. 



Similarly, the period 1892 to 1895 was one of great sun- 

 spot activity; in 1896 there was almost a minimum of sun- 

 spots, coincident with which a severe earthquake, predicted 

 by Falb, was experienced at Zante. Renewed sunspot 

 activity obtained from the end of 1896 till 1899, and an 

 almost total absence of spots between 1900 and the present 

 time. 



Looking at the chart we may notice in particular how 

 the eruptions of Vesuvius occur, this being a particularly 

 sensitive volcano. Notable outbursts occurred in 1818, 

 1822, 1855, 1867, 1872, 1889, 1891, 1900. Of these years 

 all are of sunspots minimum except 1872, which marks a 

 sharp dip on an otherwise gradual fall to a minimum, 3 and 

 1813 which occurs very near the minimum of 1810-2, and 

 is doubtful. 



Studying the outbreaks of Mauna Loa, we find the severest 

 to have taken place in 1789, 1822, 1833, 1852, 1867-8, 1877, 



1 See Lockyer, op. cit. 



2 Memoirs ot the Royal Astronomical Society, Vol. l., 1890-1. 



3 Journ. Roy. Soc. Astro, ooc, Dec. 13, 1901. 



