406 



F. A. Perret — Volcanic Vortex Rings. 



formed and, according to mv own enumeration, which lias been 

 generally adopted, viz. from the upper end of the fissure 

 downward, it is known as crater No. 7. 



The outflow of lava, which at the beginning had taken place 

 at many points along the line of the fissure, was soon localized, 

 as is normally the case, at the lowest principal opening, and 

 this continued to be the source of the magnificent stream which 

 formed so spectacular a feature of this eruption. (Fig. 3.) 



The gas content of the magma caused a semi-explosive emis- 

 sion, projecting sprays and jets of incandescent liquid masses 



Fig. 1. 



to a considerable height (fig. 4), the result of which was the 

 gradual building up of a cone of the compacted scoriae, best 

 seen in the post-eruption view (fig. 5). It is important to 

 note that neither the ejected fragments, nor the walls of the 

 crater, nor the upper portion of the cone were " dry," i. e., hard 

 or brittle, and therefore capable of being broken or crushed 

 to powder — all were in the liquid or viscous state. There was 

 no demolition of the cone itself, which was growing by 

 accretion, and there was present no old material whatever, yet 

 this crater constantly emitted a quantity of ash-laden vapor 

 having a salmon-pink tint. 



On the 30th of March at 6 a. m., the writer was proceeding 

 along the line of eruptive mouths, when the rings shown in 



