638 Jaggar — Activity of Mauna Loa. 



from time to time during the past three years. January 9 

 there was a strong column of fume rising high and bending 

 southward, and in the evening bright glow with some visible 

 fume, blowing to the southwest. 



January 10 at the Observatory the weather was brilliant with 

 strong northeast wind. The fume was seen in Kona, but day 

 and night there was no trace of fume or glow seen from the 

 Observatory at Kilauea. No fume or glow was seen there- 

 after, nor was any reported from other points. On January 

 14 at 8 a. m. the weather was calm with the Kilauea fume 

 rising high and spreading into a mushroom. There was no 

 evidence of a high wind current which might blow the fume 

 on Mauna Loa away. With clear seeing and powerful field 

 glasses not the slightest trace of fume was detected over 

 Mokuaweoweo. 



From January to June 1915 inclusive, Mauna Loa has been 

 under incessant inspection from a distance and no trace of 

 fume or glow recurred until after the summer solstice. With 

 the migration of the sunset position back of Mauna Loa thin but 

 definite fume was detected from the Observatory by Mr. H. O. 

 Wood at sundown July 30, 11 and 13, 1915, rising, or standing, 

 above Mokuaweoweo. Shortly after noon July 14 several 

 persons saw fumes above the summit. No glow has been 

 certainly seen at night, though one inexperienced observer 

 reported glow of short duration 11.30 p. in. July 10. Whether 

 this episode is a slight revival of gas activity or merely ex- 

 ceptional seeing conditions is not clear. Kilauea lava had 

 risen slightly in June. 



It may be concluded that the outbreak of 1914-15 was a 

 preliminary summit ebullition of the same type as the prelim- 

 inary outbreaks of previous eruptive periods ; those of 1870, 

 1872, 1873, 1874, and 1875, and 1876 anticipated the sub- 

 marine flow of 1877 at Kealakekua; that of Mav 1880 

 heralded the great Hilo flow of 1880-81 ; those of 1892 

 and 1896 preceded the flow from the Dewey Crater July 4, 

 1899 ; the summit action of October-November 1903 preceded 

 the Kahuku flow of 1907. 



The phenomenon in this eruption which most impressed the 

 writer, and which seemed contrary to some of the earl) 7 accounts 

 of the Mauna Loa lava fountains, notably those of William 

 Lowthian Green, was the extraordinarily light and foamy 

 character of the spurts seen above the large fountain on De- 

 cember 15 in Mokuaweoweo. The quick chilling and change 

 of color in the upper part of the fountain through cherry-red 

 and purple to black, and the blowing away of the fragments like 

 pieces of burnt paper, was utterly unlike the heavy splashes of 

 orange-red melt seen in the fountains of Kilauea. The 



