398 



SCIENCE. 



[Vol. II., No. .33. 



at the east of that town. In these jets of water, steam, 

 and gas, the temperature always ranges from 40° to 



]oo° c. 



From these elements, it appears to me, we may 

 reasonably conclude that there exists a large curving 

 line of cleavage from which arise such manifestations, 

 turning its convexity chiefly to the north, running 

 between the baths of Ischia and Furio, and passing 

 exactly througli Casamicciola (A B on the chart). 



Examining now the other principal manifestations 

 from north to south, we find in Monte Z;tle and 

 Marecocco, near Lacco Ameno, the thermal springs 

 of Santa Restituta and the stufas of San Lorenzo, 

 the fumaroles of Monte Cito, already mentioned, in 

 the stream which flows into the sea near Lacco; and 

 in the same direction, on the other slope of Epomeo, 

 we have the valley of the Searrupato, at the southern 

 end of wliich we find the hot springs of Fondolillo 

 and the stufas of Testaccio. I am assured that on 

 this line will be found other similar but much less 

 important fumaroles, also on the heights of Monte 

 Epomeo; but for want of a guide or exact indications, 

 I cannot verify the assertion. Therefore, also, there 

 is evident to me the existence of another fracture 

 running from norlh-north-west to south-south-east, 

 which crosses the first exactly at Monte Cito, almost 

 under the town of Casamicciola (C D). These two 

 grand lines of fracture are designated by broken lines 

 drawn upon the annexed chart. 



The reason which inclines me to believe that there 

 are two principal fractures, and not an intersection 

 of the fracture C D with the line of superposition 

 of one crater (that of Epomeo) upon another, sub- 

 marine and more ancient, according to the opinion of 

 the celebrated Prof, de Rossi, is the identity of the 

 manifestations along the two lines, A B and D ; 

 the thermal springs, the stupas, and the fumaroles 

 being identical in the two cases, I believe that they 

 may be more simply attributed to an identical cause, 

 without having recourse to hypotheses hitherto not 

 entirely demonstrable by facts. 



As to the phenomena which heralded the terrible 

 disaster, the information collected on the spot is some- 

 what contradictory. It is certain only, that, for some 

 days previous, slight shocks were felt with faint 

 rumblings; that the springs of Gurgitello, etc., had 

 shown irregularities of quantity and temperature ; 

 and that the fumaroles of Monte Cito, hitherto almost 

 inactive, had evinced symptoms of excitement, emit- 

 ting a peculiar hissing and quick jets of steam and 

 sulphurous acid. It is said that the wells of Casamic- 

 ciola and Forio were almost dried up, but that asser- 

 tion does not agree with the facts. There are no 

 spring wells in Casamiccola and Forio, only cisterns; 

 and a scarcity of water observed in some, not all, of 

 these, might perhaps be attributed rather to the 

 drought prevailing for some time in Ischia, than to 

 cracks in the walls of the cisterns. At Forio, I 

 learned from trustworthy persons, that, in the cis- 

 terns between San Pietro and the upper part of the 

 town, a remarkable increase of temperature was 

 observed in the water. That seems highly prob- 

 able, such cisterns being exactly in the direction 



and neighborhood of the great fracture above de- 

 scribed. 



The shook which brought desolation upon these 

 lovely regions occurred on the evening of 2Sth July, 

 at 9.2.5 P.M. I need not dilate upon its deadly effects, 

 which are already too familiar from numerous ac- 

 counts. The shock was accompanied by a horrible 

 bellowing, and lasted, apparently, twenty seconds. 

 Casamicciola, Lacco Ameno, and Forio were almost 

 levelled to the ground, with a frightful sacrifice 

 of life; Seriara, Fontana, and other lesser villages 

 suffered terrible injury. The seismic disturbance 

 was felt at Ischia, — where, however, it did but little 

 damage, — and extended to great distances, having 

 been indicated by the seismographs at the geo- 

 dynamlc observatory of Rome. 



At Casamicciola and Lacco Ameno, the shock was 

 vertical at first, and then undulatory. Information 

 obtained at the place, and the few observations which 

 I was able to make, indicate that the direction of the 

 wave at Casamicciola was from west to east, then 

 from north to south; at Lacco Ameno, from south- 

 east to north-west; at E'orio, the shock was first 

 vertical, then undulatory, and the direction from 

 north-east to south-west. In examining the localities 

 destroyed, I could observe but little in respect to tlie 

 greater or less resistance offered to the shock by build- 

 ings according to their orientation: this idea was 

 advanced by Prof, de Rossi in his account of the 

 earthquake at Casamicciola, in March, 1881, and is 

 certainly based on sound reasoning and also on 

 proved facts. But, in the first place, this shock was 

 so violent aud complete that but few walls had been 

 left standing; and secondly, at the time of my visit 

 to Casamicciola, eight days after the catastrophe, tbe 

 state of the ruins was no longer such as was caused 

 by the earthquake alone: many walls had been torn 

 or thrown down, in order to render less ditficult and 

 dangerous the work of rescuing the living, exhuming 

 the dead bodies, and searching among the ruins. 



Among other things, I could perceive that some of 

 the walls still standing presented crevices at an angle 

 inclined 30° or 40° from the vertical, with the apex 

 upward, indicating a prevailing upward and down- 

 ward movement. 



On the upper portion of the front wall of the church 

 of the Anime del Purgatorio, in Forio, I observed a 

 clean horizontal crack, showing here, also, the decid- 

 edly vertical character of the shock. This cluiracter 

 seems confirmed by the condition of a large gate at 

 a short distance to the east of Forio: only the two 

 blocks of stone forming the lower part of the jambs 

 remain in place ; the two blocks upon them are thrown 

 towards each other, projecting about six centimetres 

 from those beneath, while the upper parts and the 

 arch have fallen down. 



Between Forio and Casamicciola, it seems as if the 

 greatest seismic activity had been manifested along 

 the road joining the two towns, passing by S. M. delle 

 Grazie, and under Fango. The road Is, in fact, com- 

 pletely destroyed, and tlie little cottages that bor- 

 dered it are ruined. Besides this, the shock has 

 produced two great land-slides, which, descending 



