176 Reviews — The Water of Volcanoes. 



•does not evaporate, that it gives no rainbows, and that it is 

 immediately visible without an initial transparent zone, and these are 

 just the results to be expected if the cloud contains much sulphur. 

 But these phenomena, though they confirm Brun's statement that 

 the great white cloud consists of solid particles, do not prove the 

 absence of water ; in passing it may also be mentioned that the 

 impression one gathers from Brun's account that the solid particles 

 of the cloud are crystallized salts must be revised. 



Now it will be remembered that Brun made a series of experi- 

 ments on the hygrometric state of the Kilauea cloud, and found it 

 uniformly lower than that of the atmosphere outside. This observa- 

 tion serves as a corner-stone in Brun's statement of his case, but is 

 set aside by Day & Shepherd as quite untrustworthy. The cloud, it 

 seems, was sampled more than 250 feet from the point of emergence 

 of the gases, while the presence of oxides of sulphur must in any 

 case have lowered the dew-point very considerably. 



Thus it appears that Bay & Shepherd have kept in view the work 

 of their predecessors, and thereby materially strengthened the presenta- 

 tion of their own results. 



The following are the circumstances under which they successfully 

 collected the volcanic gases. A column of lava had worked its way 

 through the shattered floor adjacent to the great active basin, and 

 formed a lava-fountain several feet in diameter. The lava quickly 

 built up a closed spatter-dome, and at night gases could be seen 

 burning as they escaped through narrow cracks. It was clear that an 

 excess of pressure reigned within the dome, and that there was no 

 fear of admixture with air. 



The gases were drawn by a pump from the interior of the spatter- 

 dome. Twelve inches of iron pipe were inserted into the dome, and 

 behind this were 20 feet of glass tubing. The gases entered at about 

 1,000° C. Water began condensing in the pipe-line with the first 

 stroke of the pump. This prevented quantitative determinations of 

 proportions, for before sealing the tubes the pumping had to be 

 continued fifteen minutes to ensure the complete displacement of the 

 air present, and all this time water was collecting. In the end about 

 300 c.c. of water accumulated in the tubes. 



The gases found were mainly S 2 , C O2, and N 2 , with less abundant 

 H2 and C O. Hydrocarbons were absent, while chlorine, free or 

 combined, played a very subordinate role. 



The water is regarded as proper to the volcanic emanation on the 

 following grounds : — 



1. C O2 and H2 cannot coexist at 1,000° C. without the production 

 of water. 



2. The Fe O, resulting from the interactions of the short iron 

 tube and the S O2, is not likely to have been more efficacious in 

 oxidizing the hydrogen of the emanation than the 10 per cent of 

 ferrous oxide present in the magma. 



3. If the water collected represents hydrogen in the original 

 emanation, then hydrogen must constitute at least 40 per cent of 

 the emanation. This would entail violent explosions whenever the 

 emanation is liberated into air, but as a matter of observation 



