204 Scientific Proceedings, Royal Dublin Society. 



Observation (1). — Mr. Bishop, observing at Honolulu, found 

 the phenomenal sunsets to commence on the 5th September, 1883, 

 and to last up to 7^ 25"^ p.m. 



Here A = 22°. 



8=6° 16'. 



This gives the sun's place, at the close of the phenomena, 18° 22' 

 below the horizon. 



This indicates twilight phenomena intensified by some unusual 

 cause, but does not denote an extension of twilight reflexion into 

 regions of the air higher than the time-honoured traditional 40 

 miles. 



The epoch of the main eruption of Krakatoa has been fi.xed by 

 G-eneral Strachey at August, 27^^ 9^ 32°\ a.m. 



If the explosion of Krakatoa, on the 27th August, was the 

 cause of the brilliant sunset at Honolulu, on the 5th September, 

 the result is nothing short of miraculous ! 



The Editor of Nature writes, on the 20th December, with an 

 enthusiastic glow worthy of the twilights : — " The extraordinary 

 fact now comes out, that before even the lower currents had time 

 to carry the volcanic products to a region so near the eruption as 

 India, an upper current had taken them in a straight line via the 

 Seychelles, Cape Coast Castle, Trinidad, and Panama, to Hono- 

 lulu ; in fact very nearly back again to the Straits of Sunda ! " 

 [The note of admiration is not mine.] 



It is worth our while to calculate the rate at which this wonder- 

 ful journey of volcanic dust was performed. The actual distance 

 is 255° of a great circle, and the time of journey 9 days, from 

 which I calculate the speed of the train to have been 82 miles 

 per hour! This is absolutely incredible, and becomes still more so 

 when we know that the phenomena observed at Honolulu on the 

 5th September were unusual twilight phenomena, but had no 

 connexion whatever with reflexion from the upper regions of 

 the air. In point of fact, my calculation of the sun's position 

 disproves the presence of dust, or any reflecting substances in the 

 upper air. 



Observation [2) . — Dr. Ball (Dunsink). — "Sunday evening, 30th 

 December, was exceptionally fine, and the sunset was so well seen 



