SUN-SPOT MINIMA AND VOLCANIC ERUPTIONS. 45 



object of the chart is foiled, because we see several groups 

 of earthquakes, apparently coinciding with sunspot maxima. 

 Thus, in 1789, there was an eruption of Kilauea; in 1829 a 

 great Chilian earthquake ; in 1839 an earth movement at 

 Lemos, in the Ohonos Archipelago, which resulted in an 

 elevation of the island of eight feet ; in 1850 we And an 

 earthquake at Honduras, and then the great anomaly of 

 1883, of which more anon. 



All that I desire to prove is that maximum seismic 

 activity is coincident with sunspot minimum, and vice versa. 

 This, it appears to me, the chart sufficiently shows. In 

 fact, just as the sunspot curve shows a slow fall to a mini- 

 mum and a sharp rise to a maximum, so does the earth- 

 quake curve show a slow rise to a maximum, and a sharp 

 fall to a minimum. The earthquake and volcanic curves 

 show most irregularity in the period between 1878 and 1890. 

 A similar irregularity (less marked on account of paucity 

 of records) occurred thirty-five years before in the period 

 1843 to 1854. The period 1878 to 1890 I propose to discuss 

 in detail, to show that even here the seismic phenomena 

 agree in smallest details with the phenomena *of sunspots. 



From 1870 the sunspots decreased steadily to a minimum 

 in 1878. If we look at Lockyer's curve for the succeeding 

 period, we find that instead of the usual sharp rise to a 

 maximum, there was a very gradual rise, culminating in 

 April 1882, in a remarkably fine spot accompanied by vivid 

 auroral displays in our atmosphere. 1 Then there was a 

 sudden falling off in solar energy in 1883 — almost to a sun- 

 spot minimum — and then a rapid rise to the real maximum 

 in 1884. This maximum lasted through 1884, 1885 and the 

 greater part of 1886, when there was a rapid falling off to 

 a minimum in 1888-9. During this period there was at no 

 time a lasting maximum. 



1 See Monthly Notices, Royal Astronomical Society, Vol. l., p. 8. 



