Proceedings, &c, for 1885. 161 



lowest audible tones is about 20 meters; the Krakatau air- 

 wave 1,000,000 meters). The eruptions which at first broke 

 out above the sea, broke out probably after ten o'clock under 

 the sea. Previous to that hour only ash, more or less moist, 

 was ejected ; but after that time a large quantity of mud, 

 being volcanic sand mixed with sea-water, was thrown up. 

 The northern portion of the volcano gave way before the eruption 

 broke out under the sea, as is proved by the time that the great 

 tidal wave submerged the ' Ylakke Hoek.' This tidal wave 

 probably resulted from the northern portion of the volcano, an 

 immense mass of earth falling into the sea ; and where Krakatau 

 once stood there is now water of a depth of 200 or 300 metres, 

 whilst in the midst of this deep sea a rock remains of about five 

 metres above the sea — truly a remarkable occurrence. The com- 

 ponent parts of the ejected matter are chemically not sufficiently 

 known, but the analysis that has been made proves that the pro- 

 ducts do not possess acidium silicium (kiezelzeuer) in equal quan- 

 tities. The ash which Mr. Verbeek collected at Buitenzorg 

 contained, according to the analysis, 60 per cent.; a piece of pumice- 

 stone on the island of Calmeyer, 68 per cent.; a piece of obsidian 

 of Krakatau, 68 per cent.; and a fine yellow ash of the east coast 

 of Krakatau, as much as 70 per cent, acidium silicium (kiezelzeuer). 

 Further, aluminous earth (aluinaarde), 14 to 16 per cent.; 

 sulphurata ferrum, 6 per cent.; calx (kalk), 4 per cent.; soda, 4 to 

 6 per cent., and a little magnesium. 



"Between Krakatau and the island of Sebese the sea is entirely 

 filled up by pumice-stone and ash, and two islands of this matter, 

 named Steers island and Calmeyer, appear above the water. As 

 they are only a few meters high they will soon disappear owing to 

 the force of the waves. The area over which the ashes fell down 

 is estimated at the very least to be 750,000 square kilometers, an 

 extent equal to Sweden and Norway. The finer particles of the 

 ashes fell even beyond this area, as is shown by the log-books of 

 sailing vessels and steamers, but the finest particles, saturated with 

 a large quantity of vapour, have been floating for a long time in 

 the upper strata of the atmosphere, and, propelled by the winds, 

 travelled right round the world. The vapour ascending was con- 

 densed into water, and got frozen in the cold strata of the 

 atmosphere, and the refraction through the numerous ice crystals 

 produced the fine purple sunsets, which in the last months have 

 been witnessed at several places in Asia, Africa, Europe, and 

 America (no mention is made of Australia), while the particles of 

 ash obscured the light of the sun or imparted blue and green 

 colours to the sun when rising or setting. The enormous distance 

 to which these ashes have been carried is proved by snowfiakes 

 that fell in Spain and rain that fell in the Netherlands, which were 

 found to contain the very same component parts as the ash from 



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