286 



ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1913. 



somewhat from daj'' to day and considerably from year to year M'ith 

 the state of activity in the basin. The appearance of the lake and its 

 surroundings is perhaps best shown by a photograph (pi. 7) made 

 from a slight elevation above the floor of the active basin on May 

 23, 1912. 



ANALYSES OF THE LAVA. 



The composition of the liquid lava in the lake and of the solid floor 

 of the Kilauea crater near the Halemaimiau pit may be seen from 

 analysis la and lb, which follow : 



Table 1. 



Analysis la. 



Analysis lb. 



Lava from floor of Kilauea : Forty 



to 50 per cent glass; 5 to 10 per cent 



olivine; 5 to 10 per cent feldspar 



phenocryst; rest very iiue crystals. 



( Merwin. ) 



Per cent. 



SiO= 50.07 



Al:Os 13.32 



FejOa 1.92 



FeO 9. 28 



MgO 8. 01 



CaO 10. 64 



NasO . 2. 16 



KrO 0. 45 



H2O+ 0. 49 



H2O— 0.22 



CO2 - None. 



TiOi 2. 70 



ZrOz None. 



PsOs 0. 26 



SO3 None. 



CI 0. 08 



F None. 



S 0. 11 



CrsOa 0. 05 



MnO 0. 16 



NiO 0. 04 



BaO None. 



SrO— Trace. 



LisO None. 



VjOb None. 



Rare earths None. 



MoOa Trace. 



Ignition loss 0. 36 



Lava dipped from Halemaumau 

 July 23, 1911. Glass, witli 1 per cent 

 feldspar and trace of crystals of either 

 magnetite or pyroxene. Index 1.605, 

 lining of bubbles slightly higher. 



f Merwin.) 



Per cent. 



SiO: 49. 74 



AI2O3 12. 36 



Fe=0= 1.64 



FeO 10. 08 



MgO 8. 83 



CaO 10. 88 



Na20 2. 45 



K2O 0. 55 



H2O + 0. 17 



H3O— 0.05 



CO2 None. 



TiO: 2. 49 



ZrO: Trace. 



PsOb 0. 41 



SO3 Trace. 



CI 0. 10 



F None. 



S 0. 04 



CrsOs - 0. 04 



MuO 0. 14 



NiO 0. 05 



BaO Ti-ace. 



SrO 0. 07 



LijO None. 



VjOs 0.02 



Rare earths Trace. 



M0O3 0. 01 



99.96 



100.12 



After correction for 01, etc 99.89 After correction for CI. etc 100.08 



