A second tent back from the Halemaumau rim was a camping base. Ford cars were kept running from the Volcano House for the changing of crew, Mrs. Jaggar looked out for the food, and I directed repeated surveys of the position of monuments and of the observation shelter.
Meantime the lava steadily rose during July, and at one time split open the Kilauea floor making an outflow back of the shelter. The vertical angles kept track of the movements of both the liquid and the semisolid lava. The instrument was planted on the lava column itself. On one occasion, Mrs. Jaggar’s glove fell into a floor crack inside the shelter and burst into flame.
In all, there were more than 20,000 observations recorded. These were plotted on coordinate paper, and results were reduced to a smooth curve by overlapping averages. The actual curve of measurements was subjected to harmonic analysis at Yale University by Professor E. W. Brown, mathematician and specialist on motion of the moon and on lunar tides. The results showed a definite daily tide in both liquid lava and semisolid lava; of a few inches for the lunar tide, and of larger amounts for the solar effect. The curve plotted reached its greatest perfection of daily up-and-down waves during July at periods when the lava was steady. This became interrupted and ragged when accidents of drainage out on Kilauea floor pulled the liquid lava down.
14. River of Alika flow, Mauna Loa, October 6, 1917
15. Lava streaming into a sinkhole in Halemaumau lava lake, July 7, 1917
16. Sakurajima Volcano, Japan, 1914
