C. G. Rockwood, Jr.—Ischian Earthquake. 473 
Art. LIIL—The Ischian Earthquake of July 28, 1888; by 
_C. G. Rocxwoop, JRr., Princeton, N. J. 
responds in geological character, as does also the smaller island 
of Procida lying between Ischia and the mainland. Ischia 
about three miles broad. In the center of the island rises 
and for over five hundred years has been nearly silent. 
last emission of lava from its flanks occurred in 1302, since 
which time the voleanic activity has been shown only by hot 
springs and steam jets, and not infrequent earthquakes, the last 
notable one having occuared March 4, 1881. - 
Ischia is noted for its thermal springs, which with the pleas- 
ant climate make it a favorite summer resort, and during the 
Season the town of Casamicciola is usually crowded with 
Strangers. Other towns are Ischia on the east coast, Forio on 
the west and Lacco Ameno on the north. 
Before the earthquake, which wrought so much damage in 
this beautiful island on July 28, 1883, there had been some in- 
dications of unusual subterranean activity; some of the hot 
springs had shown abnormal variations of temperature, but it 
18 doubtful whether to an extent greater than at other times 
when no earthquake followed ;—there had been a number of 
slight earthquake shocks in different parts of the island,—and 
the instruments in the seismological observatories at Naples 
and Rome w 
mistakable indications of an approaching earthquake were 
observed in Casamicciola, but were concealed from the public 
so far as possible, for fear of alarming the summer visitors and 
so diminishing the gains of the hotel keepers. These indica- 
tions, beginning from a fortnight before the great earthquake 
shock, gradually increased in intensity and frequency, an 
Professor di Rossi of Rome said afterward that if there had 
been in Ischia any system of observation, by which at the 
time he could have been informed of all these phenomena, ‘the 
would not have hesitated an instant in | abet out the immi- 
nent danger of an impending seismic dis 
Casamicciola. But in the absence of observations in Ischia, 
re in increased motion. It is said also that un-— 
turbance” menacing’ 
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