V)4 Ei^oiution of the Em-tli. 



jiresent.* Tlie most reinavkaLle volcanic iiTujjtion of re- 

 cent times was that which occurred on August -G and 27, 

 1883, at the island of Krakatoa in the Straits of Sunda, 

 midway between Sumatra and Java. Streams of volcanic 

 dust were thrown to an estimated height of 17 miles, and 

 more than a cubic mile of material was expelled from the 

 volcanic crater. Accurate scientific investigations, con- 

 ducted imder the authority of the Koyal Society of England, 

 have determined that the air-waves, Avhose vibrations were 

 originated ))y this volcanic action, travelled from Krakatoa 

 to its antipodes around the entire earth not less than seven 

 times. The automatic records of the barometer at Green- 

 Avich near London responded to their influence six or seven 

 times, and similar effects were reported from Berlin, St. 

 Petersburgh, Valencia, and elsewhere. People ninety-six 

 miles away, on the island of Sumatra, were aroused from 

 their sleep by the concussions ; the sea-waves created there- 

 by destroyed numerous villages, and 36,380 lives on Java 

 and Sumatra. Incredible as it may appear, the noise was 

 heard at Macassa, Celebes Island, 969 miles away, at the 

 island of Borneo, 1116 miles away, at Victoria Plains, West 

 Australia, 1700 miles away, at Chagos Island, 2267 miles 

 away, and even at Rodiguez, 2968 miles away. The peo- 

 ple at Daly Waters, South Australia, 2023 miles away, were 

 awakened by the noise, which appeared like the sound of 

 blasting rock. The dust and powdered pumice thrown out 

 of the crater, made the entire circuit of the world more 

 than three times before it settled beloAV the region of the 

 great atmospheric currents, and was the cause of those won- 

 derful red-sunsets which we observed during so many 

 months subsequent to the occurrence of these phenomena. 

 Although this irruption left no great change in the super- 

 ficial appearance of the earth outside of the little island 

 where it occurred, we may well imagine, in contemplating its 

 effects, that volcanic action formerly played a notable and 

 important part in the phenomena of geological evolution. f 



* The crater of an extinct volcano has very recently been discovered at Red 

 Mountain, near Birmingham, Ala. Evidences of former volcanic action are 

 also found in Xorth Carolina, Xew Hampshire, and at various places along the 

 Appalachian system of mountains. 



t The phenomena at Krakatoa are described in detail in a quarto volume of 

 nearly 500 pages, recently issued by the Royal Society of England. There is also 

 a brief but interesting account, condensed from these reports, in an article in 

 a recent number of the Contemporanj Jlrricir, by Sir R. S. Ball, L.L.D., F.R.S. 



