THE GREAT ERUPTION OF SAKURA-JIMA IN 1914. 149 



This is the cause of the outwelling of it from the orifice (Text-fig. 

 29). It is a primarf/ lava-flow. 



X. Sublimation-products.— The activity manifested by nnmerons 

 volcanoes in Japan is nsnally of the explosive type, and we 

 rarely have occasion to collect the manifold products of subhmation 

 as in the case of the recent eruptions of Sakura-jima, when 

 fluent lava copiously effused from a series of vents. In saying so, it 

 does not seem to agree with the fact that fumaroles and solfataras 

 are by no means rare in this country ; but these mostly re- 

 present the last feeble stage of vulcanicity, and the sublimates 

 deposited are of oxidized and decomposition-products of low tem- 

 peratures, corresponding either to the sulphureted- hydrogen fumaro- 

 lic or to the solfataric activity (100^-200°C.), and consequently, 

 meagre in variety. 



During his second visit, in April, 1914, the writer was able 

 to approach the margin and also the solidified but stiU very hot 

 lava-flows at many points. The clefts in the ancient lava near 

 the Yuno-hira venthole were seen richly incrusted, exclusively with 

 needles of bright yeUow sulphur — the direct crateral sublimate 

 fi'om the lava reservoir, wliile at the edge of the lava stream, 

 away from the vent, the dominant deposits were variegated lava- 

 SuBu^TEs sublimates incrusting the ragged holes of ' block ' lava. 



The latter are of special interest to us, as we could not yet 

 approach the lava mass within the vent itself. The incrustation 

 consists of {a) a loose aggregate of white salmiac crystals, super- 

 posed by {h) the yeUow crystalline layer of another mineral on 

 irregular prominences, and lastly, by (c) the deep orange-red 

 crystal aggregate on tips, as in the first snow on mountain-tops 

 in early autumn. 



Unfortunately, a fine collection made on the spot has now 



