THE ERUPTION OF KRAKATOA IN 1883 239 



The colored suns were probably due to the absorption of certain rays 

 of light by the volcanic dust in the atmosphere. The large corona 

 around the sun was first recorded by Mr. Bishop at Honolulu, on Sep- 

 tember 5, 1883, and since that time it has generally been known as 

 "Bishop's ring"; the halo around the moon was noticed in the tropics 

 during the same month. These effects are referred to the lighter 

 particles of dust in the atmosphere, for in April, 1884, when most of 

 the coarser material had settled by gravitation, and the twilight glows 

 began to fade, the corona brightened, then gradually became fainter, 

 and was last observed in June, 1886, after which the sky resumed its 

 normal appearance. 



In conclusion, it may be said that the works on Krakatoa, referred 

 to above, contain many charts, maps, and barograms, and in short 

 form a complete record of all the phenomena caused by the eruption. 

 These works are more valuable than if they contained only the results 

 of the reports collected, for, by publishing the sources of information, 

 opportunity is given to any one interested in the subject to study these, 

 and thereby form his own conclusions. When other eruptions shall 

 have been treated in the same manner, more light will be shed on some 

 of the effects now slightly obscured, as the cause of the colors observed 

 in the sky and the origin of the great sea waves. Although eruptions 

 have occurred in the past, exceeding that of Krakatoa both in duration 

 and in the quantity of material ejected, such a complete history of one 

 has never been written till now. This is due in part to the spread of 

 civilization over the earth, and hence the establishment of places of 

 scientific observation. As the number of such observatories will con- 

 tinue to increase, it may be confidently predicted that the phenom- 

 ena accompanying violent volcanic outbreaks in the future will be 

 more closely observed and more widely recorded. 



