THE '^ '"'"" 



AMERICANJOURNALOFSCIENCE 



[FOURTH SERIES.] 



Aet. XVI. — Volcanologic Investigations at Kilauea, with 

 Plate I (frontispiece)* ; by T. A. Jaggar, Jr. 



Contents 



Introduction ; Magmatic Gases. 

 Mechanism of Heating. 



Is lava lake hotter below surface ? 



Atmospheric oxidation of magmatic gas. 

 Evidences of Convection ; the Duplex Lava Column. 



Variable surface radiation. 

 Evidences of Shallowness of Liquid Lava Lake ; the Bench Magma. 



Lava islands. 



Shoals, sinkholes and conduits. 



Summary, duplex lava column. 



Consistency of bench magma. 

 Evidences of Heat from Gas Oxidation. 



Types of flames. 



Gases responsible for flames. 



Distribution crusting and fountaining. 



Problems of fountain mechanism. 



Mechanism of different types of fountains. 



Construction upon lake bottom. 



Sinkhole cascades. 



Condensation by de-vesiculation. 



Multiple fountaining of 1910 to 1912. 



Disappearance of liquid lava during low levels. 



Heating mechanism in bench magma. 

 Experiments to Determine Differential Temperatures. 



Queries concerning temperature. 



Reconnaissance and method. 



Temperature of lava lake. 



Temperatures of grottoes and flames. 



Summary of temperatures. 



Refusion. 



Furnace effect. 



Relative coolness of lake. 

 Experiments to Determine Depth and Consistency. 



Queries concerning depth and consistency. 



Measurement of depth. 



Confirmation of soundings by subsequent subsidence. 



Summary of depth and consistency. 

 Conclusion. 



* For explanation of Plate I see bottom of p. 162. 



Am. Jour. Sci.— Fourth Series, Vol. XLIV, No. 261.— September, 1917. 

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