DALY. — THE NATURE OF VOLCANIC ACTION'. 4 O 



It seems certain that such slow transfer of magma could not keep 

 the temperature of surface lava of the lake at anything like the ob- 

 served point. On the average, every square centimeter of the lake's 

 surface in 1009 radiated about one calory i)cr second or 86 400 cala. 



?~e e r j-oo 



FiorRE 5. Sketch map (after J. M. LydRate) of Halemaumau in July, 

 1909. .\rrow3 indicatf the general trend of currents in tlie lava lake during 

 that month. The i>ositii>n.s of "Old Faithful" and of the more important 

 caves eroded by the licpiid lava in the "Black Ledge" are shown. Tigurea 

 Bhow depths below the " Rest House." 



per day. Taking .35 as the mean specific heat of basalt (1200°-1 300°), 

 this implies a daily heat loss corresponding to a temperature fall of 

 loO°C. in a vertical column of lava more than 2400 meters deep, and 

 one square centimeter in area at its upper surface. Evidently, other 

 and much more effective agencies must be at work to keep Kilauea 

 active, year in and year out. 



