370 THE POPULAR SCIENCE MONTHLY. 



of July, of the ship (on board which he was returning to England) 

 through extensive fields of pumice spread over the ocean north and 

 south as far as the eye could reach. The vessel passed the volcano on 

 the 9th, but till the evening of the 10th, when the steamer would be 

 about a degree to the west (a little northerly) of her noon position, 

 which was 102° 25' east longitude, 6° 20' south latitude, no pumice was 

 observed. During the whole of the 1 1th the vessel was surrounded by 

 the pumice-sheet, which about noon of the 12th, in 93° 54' east longitude, 

 5° 53' south latitude, suddenly terminated, shortly after it had appeared 

 in greatest amount, while a current had been encountered after leav- 

 ing the entrance to the straits, running against the ship's course at the 

 rate of a quarter of a mile an hour. The pumice -nodules were consid- 

 erably worn, but many pieces were observed as large as a child's head. 

 Several lumps were picked up infested with barnacles, of from one to 

 one and a half inch in length, which represented at least some four 

 or five weeks' growth. 



The specimens of pumice obtained at sea have been submitted to 

 Professor Judd and the committee appointed by the Royal Society for 

 the examination of the phenomena connected with the eruption. If, 

 on analysis, they should prove different in composition from specimens 

 obtained directly from the volcano, a different origin will have been 

 established for them ; but, should both turn out to have identically the 

 same components, it will not necessarily prove that both have come from 

 the same crater. The Peninsular and Oriental Company's steamer 

 Siam, on her voyage from King George's Sound to Colombo, sailed for 

 four hours, on August 1st, through a similar "lava " (puraice) sheet, in 

 latitude 6° south, and 89° east longitude, the nearest land, the coast of 

 Sumatra, being seven hundred miles off, and the current then running 

 eastward at from fifteen to thirty miles a day. The soundings at the 

 spot reached two thousand fathoms. Mr. Forbes, who incidentally 

 referred to the eruption when reading his paper before the society on 

 the 28th of January last, suggested that the sounds heard in Batavia 

 on the 20th of May, which were altogether unperceived at spots so 

 near Krakatau as Anjer, Merak, and Telok-betong, which would be 

 inexplicable if they really originated there, were the result of a sub- 

 marine eruption in the Indian Ocean, somewhere southwesterly from 

 Java Head ; and that the tremors were propagated thither perhaps by 

 continuous strata connecting the locale of the outburst with Batavia, 

 Buitenzorg, and more especially with the hills to the southwest, where 

 the manifestations were so distinctly perceived. We know from Mr. 

 Darwin's * and Mr. Forbes's \ observations, that the center of volcanic 

 disturbance does exist in that direction, in the Keeling Atoll, situated 

 six hundred miles west by south from the mouth of the straits. 

 Whetber or not anything unusual has been experienced in these 



* " Narrative of Survey Voyages of the Adventure and Beagle," vol. iii. 

 f "Proceedings of the Royal Geographical Society," December, 1879. 



