586 DAY AND SHEPHERD WATER AND VOLCANIC ACTIVITY 



Table 1 



Analysis 1-a 



Lava from floor of Kilauea: 40 to 

 5*0 per cent glass ; 5 to 10 per cent 

 olivine; 5 to 10 per cent feldspar 

 phenocryst; rest very fine crystals. 

 ( Merwin. ) 



Per cent 



Si0 2 50.07 



A1 2 3 13.32 



Fe 2 3 1.92 



FeO 9.28 



MgO 8.01 



CaO 10.64 



Na 2 2.16 



K 2 0.45 



H 2 0+ • 0.49 



H 2 0— 0.22 



C0 2 . . none 



Ti0 2 . 2.70 



Zr0 2 none 



P 2 O s 0.26 



S0 3 none 



CI 



S ... 



Cr 2 3 ........... . '. ....... . 



MnO ...:........ 



NiO 



BaO 



SrO .... 



Li 2 none 



V 2 5 , none 



Rare earths none 



Mo0 8 trace 



Ignition loss 0.36 



0.08 

 none 

 0.11 

 0.05 

 0.16 

 0.04 

 none 

 trace- 



Analysis 1-b 



Lava dipped from Halemaumau 

 July 23, 1911. Glass with 1 per cent 

 feldspar and trace of crystals of either 

 magnetite or pyroxene. Index 1.605, 

 lining of bubbles slightly higher. 

 ( Merwin. ) 



Per cent 



Si0 2 49.74 



A1 2 3 12.36 



Fe 2 3 



1.64 



FeO 10.08 



MgO ... . .- 8.83 



CaO 10.88 



Na 2 2.45 



K 2 ...'.' . . 0.55 



H 2 0+ • 0.17 



H 2 0— . .' 0.05 



CQ 2 none 



Ti0 2 



2.49 



Zr0 2 ........ trace 



PA, 0.41 



SO s trace 



CI .................. 0.10 



F , none 



S 0.04 



Cr 2 3 0.04 



MnO 9.14 



NiO 0.05 



BaO . . . . . ...... . ; ;-. . trace 



SrO 0.07 



Li 2 none 



V 2 5 0.02 



Rare earths trace 



Mo0 3 0.01 



99.96 



100.12 



After correction for CI, etc 99.89 After correction for CI, etc 100.08 



The Gases and different Ways of studying them 



The problem of collecting volcanic gases which are satisfactory from 

 the chemical viewpoint is a much more difficult matter, as has been al- 

 ready intimated. Hot gases of more or less complicated composition dis- 

 charged from an active volcanic vent into the air undergo immediate and 

 violent chemical and temperature changes, the consecuences of which, 



i 



