J. D. Dana — Eruptions of Kilauea and 3ft. Loa. 97 



1852 1859 1868 1887 



A 2500 . 3000 10,000 7000 



B 200-700 300-400 200—; 600? 200? 80. 



Owing to the height of the column above the level of the 

 outlet in 1868, 10,000 feet, the hydrostatic pressure should then 

 have been greatest : the force from the vapors in the lava- 

 column, least ; and the friction in the very long passage-way 

 from the broken conduit, the most obstructing. 



The second source of ejecting and fracturing pressure men- 

 tioned above is the probable origin of the fractures which 

 sometimes cut through the walls of a crater to the summit ; 

 and if the vapors producing the pressure are generated over a 

 source of liquid lava, the fissures would necessarily become in- 

 jected with lava which might flow out above in a stream. Cases 

 of this kind about Kilauea occurred at the eruptions of 1832 

 and 1868, (xxxiii, 445, xxxiv, 92) ; and Mr. W. T. Brigham and 

 Rev. J. M. Alexander mention others, of uncertain date, about 

 the summit crater. 



Mr. Alexander speaks of a " cataract of lava" descending the 

 walls into the crater from the summit ; and farther south, of 

 two other similar cataracts ; and at the summit he found the 

 deep fissure from which the cataracts had been supplied with 

 lava, and ascertained that it had also poured out an immense 

 stream northward upon the first plateau and thence southward 

 into the central crater. " On the southwest side of the crater 

 there had been another eruption from fissures that were still 

 smoking, and the eruption had sent a great stream southward 

 toward Kahuku and had also poured cataracts into the south 

 crater" from all sides." " The flows were from some of the 

 highest parts of the brim ;" and " from the brink there had 

 been large flows down the mountains." " These outbreaks from 

 fissures around the rim indicate that the lava has rather ]30ured 

 into the crater than out of it ; and also that it has flowed from 

 such fissures in vast streams down the mountain side." These 

 cases perhaps date from the eruption of 1880, the last that 

 preceded Mr. Alexander's investigation of the crater. 



Such events if attending an eruption belong to its very be- 

 ginning before the lava is drawn off from the crater. They 

 may occur at other times ; that they do so is not yet certain, 

 except in a small way within Kilauea, about the lava-lakes, 

 (xxxv, 228). 



3. The Outflows and the circumstances attending them. 



1. The source. — An outflow of lava may commence as a stream 

 or as a fountain. In either case, the pent-up vapors of the lava- 

 column make their forcible escape with the lava ; and a cone 



Am. Jour. Sct. — Third Series, Vol. XXXVI, No. 212. — August, 1888. 

 1 



