266 



KNOWLEDGE 



[December 2, 1895. 



These are regarded as parts of the rim of the great crater- 



tVr/n/ cy> 



VtRLATEN I 



f'tttliii i/rr i \,} 



Jl.<iii.i M-l 



.^. A KRAKATOA 



CH AN N E.L 



Fig. 2. — Chart prepared after the Eruption. The shaded portions 

 show the islands according to the old chart. 



basin of Santorin. The dotted line on the map of 

 Krakatoa (Fig. 3j is an ideal completion of the cii'cuit of 

 this volcanic stump, the whole representing a circumference 

 of about twenty-five miles. Its underlying rocks indicate 

 its probable existence in Pleistocene times. 



Within the circle referred to we have set two thick little 

 rings. They represent two points of eruption, presently to 

 be referred to, /.(■., Perboewatan, at the north end, and 

 Danan near the middle of Krakatoa Island. 



Lanij f 



iBitiat ^"imKff 



KRAKATOA 1 



/..../^fjA M-lr 



Fig. 3. — Map of the Krakatoa tiroup, before the Eruption. 

 The dotted line indicates, approximately, the submerged 

 edge of the Great Crater. 



For two hundred years the igneous forces beneath 

 Krakatoa remained dormant. In September, 1880, pre- 

 monitory shocks of earthquake were felt in the neighbour- 

 hood. At length the inhabitants of Batavia and Buitcn- 

 zorg were startled on May iOth, 1sk3, by booming sounds 

 •which came from Krakatoa, one hundred miles distant. 

 A mail steamer passing through the Strait, had her 

 compass violently agitated. Next day a sprinkling of 

 ashes was noticed at some places on each side of the Strait, 

 but towards evening a steam-column rising from Krakatoa 

 revealed the locality of disturbance. The commander of 

 the German war- ship Elisabeth, while passing, estimated 



the dust-column to be about thirty-six thousand feet, or 

 seven miles high. 



Volcanic phenomena being common to that region, no 

 fears were entertained by the inhabitants in the vicinity. 

 An excursion party even started from Batavia to visit the 

 scene of action. They reached the island on May 27th 

 and saw that the cone of Perboewatan was active, and that 

 a column of vapour rose from it to a height of less than 

 ten thousand feet, while lumps of pumice were shot 

 up to about six hundred feet. Explosions occurred at 

 intervals of from five to ten minutes, each of these out- 

 bursts uncovering the liquid lava in the vent, the glow of 

 which lighted up the overhanging steam-cloud for a few 

 seconds. 



Shortly after this visit the activity diminished. But on 

 June llith it was noticed at xVnjer that the height of the 

 dust and vapour-column, and likewise the explosions, were 

 again increasing. On the 21th a second column was seen 

 rising. At length, Captain Ferzenaar, chief of the 

 Topographical Survey of Bantam, visited Krakatoa 

 Island on August 11th. He found its forests destroyed, 

 and a mantle of dust near its shores was twenty mches 

 thick. Three large vapour-columns were noted, one 

 marking the position of the crater of Perboewatan, while 

 the other two were in the centre of the island, and, of the 

 latter, one was probably Danan. There were also no 

 fewer than eleven other eruptive foci, from which issued 

 smaller steam-columns and dust. This was the last 

 report prior to the great paroxysm. During the next 

 two or three weeks there was a decline in the energy of 

 the volcano, but on the afternoon of Sunday, August 2Gth, 

 and all through the following night, it was evident that 

 the period of moderate eruptive action had passed, and 

 that Krakatoa had now entered upon the paroxysmal 

 stage. ''From sunset on Sunday till midnight, the 

 tremendous detonations followed each other so quickly 

 that a continuous roar may be said to have issued from 

 the island." The full terrors of the eruption were now 

 approaching. The distance of ninety-six miles from 

 Krakatoa was not sufiicient to permit sleep to the inhabi- 

 tants of Batavia. " All night volcanic thunders sounded 

 like the discharges of artillery at their very doors." On 

 the next morning there were four mightv explosions, i.e., 

 at 5.30, 6.41, 10.2, and 10. .52 (Krakatoa time). The 

 third, /.('., at 10.2, was of appalling violence, and it gave 

 rise to the most far-reaching effects. The entire series of 

 grand phenomena at that spot extended over a little more 

 than thirty-six hours." 



Captain Thomson, of the Medeu, then seventy-six 

 miles E.N.E. of Krakatoa, saw a black mass like smoke 

 rising into the clouds to an altitude estimated at not less 

 than seventeen miles. The eruption was also viewed by 

 Captain Wooldridge at a distance of forty miles. He 

 speaks of the vapory mass looking Like " an immense wall, 

 with bursts of forked lightning, at times like birgo serpents 

 rushing through the air." After sunset this dark wall 

 resembled '■ a blood-red curtain with the edges of all shades 

 of yellow, the whole of a murky tinge, with fierce flashes 

 of lightning." Two other masters of vessels, at about the 

 same distance from the volcano, report seeing the mast- 

 heads and yardarms of their ships aglow with electric fire. 

 Such effects seem to be easily explicable. When w-e con- 

 sider how enormous must be the friction going on in the 

 hot air, through the clash against each other of myriads 

 of particles of volcanic dust, during ejection and in their 

 descent, it is evident that such friction is adequate to 

 produce a wide-spread electrical disturbance in the sur- 



* It ceased at about 2. 30 a.m. on Tuesday, August 28th. 



