July 30, 1915] 



SCIENCE 



149 



lake level, whiclt was 446 feet. The length of 

 the lake was 435 feet, the floor 750 feet. 



Until the thirteenth, little change took place 

 in the lake. The fountaining was active, espe- 

 cially at Old Faithful, the streaming nor- 

 mally active with sudden reversals of direction, 

 and splashing caves. On the twelfth and 

 thirteenth, new flows spread south and north 

 from the west cones, and the old floor had 

 tilted dovmward on the west, indicating that 

 the floor which fills the Halemaumau pit is 

 subject to differential tilting movements from 

 loading or unloading, irrespective of the rela- 

 tive stability of the walls of the pit. For the 

 first time in 1914, the main lake overflowed, 

 the flows moving southward. 



From December 18 to 22, at the time of 

 the winter solstice, a rise took place in the 

 lake. The rise started with tremendous flows 

 pouring from the northwest pond north and 

 south, reaching the main lake on the north at 

 the east arm, on the south at the southwest. 

 With these flows, the crag and the west cones 

 rose like islands. The rate of flow was, at the 

 source, one half to one mile an hour, and the 

 duration of the flow nineteen hours. On the 

 succeeding days there were similar flows, al- 

 ways coming either from the northwest pond or 

 from the cones. In the lake, meantime, the 

 currents from the east met smaller ones from 

 the west in the vicinity of Old Faithful, caus- 

 ing violent fountaining. With the sudden 

 rises there was frequently a diminution in the 

 fountaining, the east arm and northwest pond 

 skimming over. 



The flows occasionally ran into caverns or 

 ovens on the southera floor. In the case of 

 one of the ovens, blobs of molten lava were 

 thrown to a height of 50 feet as the torrent 

 poured in. The crag rose with the flooding of 

 the floor and with the rise in the lake, until on 

 December 28 it was 47 feet above the lake. 



On the twenty-eighth a flow poured around 

 the north side of the crag and overwhelmed 

 the east arm. Above this arm there was an 

 open lava tube, about 10 feet in diameter, 

 which had been exposed for several months. 

 Into this tube, on th® northeast wall of Hale- 

 maumau, the flow ran, with a crackling noise, 



for thirty hours or more, forming a pseudo- 

 intrusive body. The flow was in the form of a 

 cascade, with a ten-mile-an-hour current. Two 

 days later the frozen cascade was covered by 

 another flow. About March 1, 1915, a slide 

 uncovered the filled entrance to the tube. 



The closing days of the year were marked by 

 new flows from the main lake as well as from 

 the cones and the northwest pond. Several 

 flows from the latter cascaded directly into 

 the main lake at the west end, when the level 

 of the lake was 10 feet below the rim. New 

 Tear's Eve witnessed jets of lava spurting to 

 a height of 100 feet from the top of a cone on 

 the southwest floor. The southeast cove of 

 main lake was divided in two parts by a pro- 

 jecting lump of spatter. The northern portion 

 was a seething cauldron into which lava poured 

 with incessant fountaining, the cauldron 

 maintaining a level two to three feet lower 

 than the main lake. The southern portion of 

 the cove was normally fuU of lava to the level 

 of the main lake. 



The maximum activity was attained during 

 the first few days of January, 1915. On the 

 second the lake had attained a level of 368 

 feet, and was one foot below the bank. On 

 the following day the northwest pond had in- 

 creased in size and a west pond had developed. 

 The southeast cove had lost its partition and 

 resumed its normal activity. The fumes on 

 this and the preceding day were less dense than 

 at any other tirae in the period of activity. 



The relative movement of the lake and crag 

 on the north are noteworthy. On December 9 

 and 23, the crag was 58 feet above the lake al- 

 though the lake had risen 41 feet. On January 

 2, the lake had risen 12 feet more, but the crag 

 had subsided 12 feet as it was only 23 feet 

 above the lake. 



Indications of slow subsidence were noted 

 after January 4, in the increasing fume cloud, 

 falling lava, enlargement of the ponds, and 

 scarcity of new flows. On the 5th there were 

 new flows on the floor from the south and 

 southeast coves, and a definite pond had formed 

 southwest. This additional pond made the 

 third in a semicircle at the west side of the 

 pit, each being about 100 feet long and oval in 



