VULCANOLOGY AND SEISMOLOGY. 



By Charles G. Kockwood, Jr., Ph. D., 



Frofeasor of Mathematics in the Collige of Neiv Jersey, Princeton, N. J. 



The following' snmmary for the years 1883 and 1884 cannot pretend 

 to be comijlete. Neither the space nor the time at command would al- 

 low of even the mention of all that has happened or all that has been 

 done and written in these departments in the two years. The writer has 

 therefore preferred to make somewhat more full the account of those 

 things which seemed most deserving of such record, even at the expense 

 of passing unnoticed many things of interest and much good work that 

 has been done, especially in foreign countries, where it is less accessi- 

 ble to an American writer. For all else the reader must refer to the 

 authorities mentioned in the bibliography. The subjects will be treated 

 in the following order : 



Vulcanology : 



Volcanic eruptions of 1883 and 1884. 



Investigations of former volcanic activity. 

 'Seismology : 



Earthquake lists of 1882 and 1883. 



Special earthquakes of 1883 and 1884. 



Lists of former earthquakes. 



Theories of earthquakes. 

 Seismometry : 



Instruments and their records. 



VULCANOLOGY. 



In the last days of August, 1883, the Straits of Sunda were the scene 

 of a catastrophe exceeding in magnitude and destructiveness anything 

 that has heretofore come within the observation of civilized men. It has 

 been the subject of numerous publications in the various languages (see 

 bibliography,) from which the following condensed account is drawn: 



The island of Krakatoa lies midway between Java and Sumatra, iD 

 the Strait of Sunda. It was about live miles long by three miles wide> 

 rising into a triple mountain peak 2,700 feet high, and clothed with veg- 

 etation from base to summit. Near it are two small islands, Verlaten 



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