i8z THE POPULAR SCIENCE MONTHLY, 



Herculaneum, and Stabise, in the year 79. The eruption of Kra- 

 katoa, in 1883, exceeded, in all probability, in its deadly effects, 

 and as a wonderful phenomenon of nature, the outburst of Vesu- 

 vius in the year 79. It is shown, in the report of the Krakatoa 

 Committee of the Royal Society, that the detonations caused by 

 the explosive action were heard a hundred and fifty miles away. 

 Captain Thompson, of the ship Medea, sailing at a point seventy- 

 six miles northeast of Krakatoa, saw a black mass like smoke 

 rising into the clouds to an altitude which was estimated as not 

 less than seventeen miles. All the eye-witnesses agree as to the 

 splendor of the electrical phenomena. The old crater of Krakatoa 

 was eviscerated, and a cavity was formed more than a thousand 

 feet deep. On the morning of the 27th of August three vessels at 

 the eastern entrance of the Strait of Sunda encountered the fall 

 of mingled dust and water, which soon darkened the air, and cov- 

 ered their decks and sails with a thick coating of mud. Some of 

 the pieces of pumice falling on the Sir R. Sale were said to have 

 been of the size of a pumpkin. All that day the three vessels were 

 beating about in darkness, pumice-dust falling upon them in such 

 quantities as to employ the crews for hours in shoveling it from 

 the decks and in beating it from the sails and rigging. The speed 

 and distance attained by the pumice ejected from the volcano may 

 be conceived from the fact stated in Mr. Douglas Archibald's con- 

 tribution to the report, that dust fell on September 8th more than 

 thirty-seven hundred English miles from the seat of the eruption. 

 The great mass of the pumice was of a dirty, grayish-white tint, 

 and was very irregular in size. 



The dust ejected from Krakatoa did not all fall back at the 

 same time upon the sea and the earth. The lightest portion formed 

 into a haze, which was as a rule propagated westward. Most ob- 

 servers agree in regarding this haze as the proximate cause of the 

 twilight glows, colored suns, and large corona which were seen for 

 a long time (more than two years) after the eruption. The haze 

 was densest in the Indian Ocean and along the equatorial belt, 

 and was often thick enough to hide the sun when within a few 

 degrees of the horizon. 



I hope I have succeeded in showing that infinitely small ob- 

 jects, no larger than particles of dust, act important parts in the 

 physical phenomena of nature. 



Mr. H. "W. Seton-Karr tells, in one of his books of travels, of his ascent of 

 one of the spurs of Mount St. Elias, following the track of a brown bear with 

 always an uneasy expectation of meeting the animal itself, to the height of seven 

 thousand two hundred feet. Here the wonderful spectacle was presented of no 

 less than seventeen thousand square miles of glaciers stretching over the face of 

 the country. Excepting Greenland, according to this traveler, these glaciers are 

 the most extensive in the world outside of the arctic and antarctic regions. 



