i59 
1882.] Earthquake Commotion and Sun Spots . 
determined from the precession of the equinoxes, has likewise 
been ena< 5 ted in great dependent cycles. If so, we might 
think to see the resolution of the crude Newtonian theory of 
gravity and squares of the distances, into a known harmo- 
nious reality — electricity ; and the sun, from its late 
execrable conduct, would take its place then among the 
worst regulated of magnetic lights. 
And now another matter. If earthquakes and volcanoes 
are in activity at the minima and maxima of sun spots, and 
their period coincides, as in spite of previous conviction I 
now own with these epochs, the phenomenon must, as I 
before intimated, be considered as due both to the expansion 
and contraction of the earth’s crust, rather than to its 
secular contraction, as is often stated. This, also, is the 
only aspeCt of the question which is true to work upon. It 
might likewise appear to some that, however fair the 
reasoning from the known to the unknown might be, a 
seismic sun spot table, constructed from the data furnished 
by igneous commotions alone, might want checking by other 
and independent phenomena. Here, of course, the laborious 
searchers in old records are again in request, and each 
branch of golden sun lore has to be culled from out the dusk 
of the monkish cell and archives of the past. My own pre- 
disposition has been greatly for biology, and when writing 
my late work, “ InseCt Variety,” I was led to recognise the 
faCt that the multiplication of locusts in southern Europe 
recurred regularly at each epoch of minimum sun spots, and 
that their dissemination northward, and final disappearance, 
ensued on the arrival of the succeeding maximum season. 
Any way the period is always marked, and communications 
on this subject have been already made by me to the daily 
papers, the “ Journal of Science” for August, 1881, and 
more lately to the Linnean Society. By its means, I have 
now succeeded in checking certainly some six minimum- 
maximum periods in my seismic table before the date of 
actual instrumental observation, and, as a faCt, Koppen 
indicates one cycle, 1333 to 1336, far back in time when 
seismic records are confined to the area of the Old World 
alone, and I have my doubts whether anyone then really 
knew the existence of sun spots at all. Other checks are 
to be found in the deviations of the compass and in the 
sudden appearance of the Aurora Borealis. And even 
should the intrinsic value of these last records be not great 
on the whole, the surprise of a fine Aurora in the south of 
England — as, for example, those magnificent crimson flashes 
which broke over London on the nights of the 24th and 25th 
