VULCANOLOGY AND SEISMOLOGY FOR 4886. 



By C. G. RocKWOOD, Jr., Ph. D., 

 Professor of Mathematics in the College of Xeiv Jersey, Princeton, N. J. 



In the preparation of this summary the author has made use of the 

 following sources ot informatiou : 



1. The current issues for the year of the following ])eriodicals, viz : 

 Science; ISTaturej American Journal of Science; ComptesReudus; La 



Nature ; Le Tour du Monde ; Gaea ; Petermaun's Geograph. Mitthei- 

 lungen ; Mittheil. der K. K. Geogr. Gesellschaft, Wien ; Neues Jahrbuch 

 fiir Mineralogie, etc. ; Mineral, u. Petrogr. Mittheil. (v. Tschermak); Jahr- 

 buch der K. K. Geolog. Eeichsanstalt. Wien. 



Transactions of Seismological Society of Japan ; Proceedings of Royal 

 Society, London, 1885 ; Report of Brit. Assoc, for Adv. Science, 1885. 



2. Of the books, and separate reprints in the Bibliography, about 

 one-half have come under the personal examination of the writer. 



The subject matter will, as heretofore, be arranged under the follow- 

 ing heads : 



VuLCANOLoaY. — Yolcanic phenomena of 1886, volcanic phenomena 

 of previous years, causes of volcanic action. 



Seismology. — Earthquakes of 1886, earthquake lists of 1885, cata- 

 logues of earthquakes of previous years, study of earthquakes. 



Seismometey. — Instrumental records, instruments. 



VULCANOLOGY. 



In describing the eruption of Etna, May 18 and 19, 1886, O. Silvestri 

 notes that after the great eruption of August, 1874, by which the 

 mountain was fractured from north -northeast to south-southwest, he 

 predicted that another eruption would occur on the southern side of the 

 mountain, where the fracture had not closed. This prediction was ful- 

 filled in May, 1879. Again, in May, 1883, there was a third eruption 

 from the same opening; and it is still again from the same crevasse 

 that the lava has issued in 18S6. (Compt. Rend., cii, 12-52.) The erup- 

 tion of 1886 was somewhat severe, and at ene time threatened the de- 

 struction of the village of Nicolosi. H. Silvestri calculates that the 



289 



H. Mis. 600- — 19 



