PLATE II. 



A. Halemaumau, the crater in the Kilauean sink, taken from the Uweka- 

 huna triangulation station by H. E. Wilson, Aug. 29, 1908. Diameter of 

 erater about 500 meters. 



B. The lava lake at Kilauea, taken at night (July, 1909) with an exposure 

 of somewhat less than one quarter of a second, showing an outburst of " Old 

 Faithful," an intensely luminous cave in the background, and a few of the 

 brighter cracks in the " scum " on the lake. 



