396 



SCIENCE. 



[Vol. II., No. 33. 



is the large excess in the upper lake region, New 

 England, and the upper Mississippi valley ; and 

 the large deficiencj' in the southern states, which 

 materially affected the crops in that section. The 

 following table contains the rainfall record : — 



Average precipitation for July, 1883. 



eye, taking advantage of the smoky state of 

 the atmosphere caused bj' forest-fires. 



The accompanying chart represents the dis- 

 tribution of tlie mean pressure, temperature, 

 and wind direction for the month. 



In some portions of the southern states, the 

 deficiencies were even greater than those re- 

 corded in the above table : at New Orleans 

 the rainfall was 5 inches less, and at Vicks- 

 hurg 6.82 inches less, than in July, 1882. 

 Eastport, Me., reports a fall of 5.24 inches in 

 10 hours, on the 14th inst. 



The local storms reported are very numerous, 

 and much damage resulted from rain, lightning, 

 and hail. The greatest damage from rain was 

 at Loudon, Ont., on the 10th, due to the over- 

 flowing of the river Thames. Much damage 

 to crops, cspecialh' in the west, was caused bj' 

 hail. A vessel in lake Michigan reports a 

 hail-stone weighing two pounds. The rivers 

 were not high, except at the veiy beginning 

 of the month ; and navigation was suspended 

 in the Savannah and Cumberland rivers on 

 account of low water. 



Among miscellaneous phenomena may be 

 noted the brilliant aurora on the nights of the 

 29th and 30th, which was observed from 

 Dakota eastward to New England, and south- 

 ward to southern Virginia. Slight earthquake 

 shocks were experienced in Nevada, Illinois, 

 California, and Kentucky' ; though insignificant 

 in comparison with that on the island of Ischia, 

 of which a condensed account is given. Sun- 

 spots were numerous ; and an instance is noted 

 in Oregon, of their observation with the naked 



THE EARTHQUAKE OF JULY 28, 18SS, 

 IN THE ISLAND OF ISCHIAA 



Having visited the island of Ischia by order of 

 the iiispector-in-chief of the Royal corps of mining 

 engineers, a few days after the earthquake of the 

 2Sth July, I present some observations made during 

 my short tour; and begin with a brief account of 

 the topographical and geological conditions of the 

 island, which last are, without doubt, the chief cause 

 of the terrible disaster. 



The formation of the island of Ischia is wholly 

 volcanic, with the exception here and there of some 

 argillaceous elevations, of marine formation, but de- 

 rived from the disintegration of pre-existing volcanic 

 matter. In connection with the islands of Vivara 

 and Procida, it belongs to the volcanic group of the 

 Carapi Flegrei, and forms its western limit. 



The aspect of the island as seen from the north is 

 pleasant and delightful, although with deep hollows 

 crowned by tlie towering and indented crest of 

 Epomeo, rising to an elevation of 792 metres. 



The town of Casamiceiola, now destroyed by the 

 terrible scourge, was built on the side of Epomeo 

 sloping towards the north, upon two small hills, be- 

 side which flow two of the principal streams of the 

 island, one near the mountain, fed cliiefly by the 

 waters of thermal springs, the other emptying into 

 the sea near Lacco Ameno, a little farther to the 

 west; these run from south to north; and another 

 more important stream, called the Scarrupato, runs 

 from north to south, flowing through a deep and pre- 

 cipitous valley on the southern slope of the island, 

 having on its banks the villages of Fontana, Serrara, 

 Moropane, and Barano. These last two streams are, 

 in my opinion, very important; being, as we shall 

 see, situated directly in one of the principal gorges 

 of the island. 



Forio is on the west coast, upon a plain .gently 

 rising towards Epomeo, bordered upon the north by 

 Mount Zale. E.astward of Casamiceiola are seen the 

 volcanoes of Monte Rotaro and Montagnone (respec- 

 tively 21.5 and 236 metres in height. ) 



According to Fuchs, the most ancient terrane of 

 the island is composed of the tufa of Epomeo, of a 

 clear green color, containing numerous sanidin, and 

 sometimes pumice and lapilli. On this rest, here 

 and there, strata of pumice and tracliytic tufa, and 

 depositions of trachyllc lava, with beautiful sanidin 

 from the mountains Rotaro, Mont.agnone, Tabor, 

 Garofali, etc., which may also be seen on the road 

 from Lacco Ameno to Forio, forming the promontory 

 of Zale. 



On the tufa of Epomeo rests a great extension of 



1 Translated from the Italian of L. Baldacci of the Royal 

 corps of mining engineers {Soil. R. com. geol, 1883, nos. 7, 8). 



