To shorten a long story, the second terminal was lowered into a seemingly safer liquid place. A wave of the melt slapped and strained the pipe, and though it was recovered, no electric resistance reading was obtained at any time with the box at the rim of the pit. Close to $1,000 in equipment was lost. The resistance pyrometer is a sensitive tool in the laboratory, for giving precise degrees of temperature in the region of 1200° Centigrade, supposedly the melting point of basalt. But it was unsuited for the rugged bubbling of basalt slag, where flaming gases and chilling air play more important parts than mere melting.
Fortunately Shepherd and Perret were not at the end of their resources. There still remained the thermocouple, a simpler pair of wires of platinum and iridium encased in a steel tube. The connectors from these go to a simple galvanometer in the hands of the operator. The trolley could still be used, and the thermocouple pipe had no glass inside it to be shattered. A temperature of 1000° Centigrade was recorded in a bubbling area, and this was considered good enough for an approximation.
Another experiment was to lower an iron bucket into the liquid, and pull it up full and dripping with black lava glass. This was sent off to Washington for analysis. Afterwards the lava lake went down, no more experiments that year were possible, and Perret began the plotting of a curve of high and low in the rise and fall at the bottom of the pit.
It may seem extravagant to waste valuable apparatus on such seemingly small results; but as a matter of fact, the Shepherd-Perret journal of the summer of 1911 was epoch-making in the history of volcanology and in the work of the Hawaiian Volcano Observatory. It proved that skilled observers could dwell inside an active crater and there apply their skills in photography, chemistry, note-taking, and continuous publication. The substance of active lava lakes was proved to have viscosities and solidifications quite different from those implied by gases, and it was shown that different types of thermometers gave negative or positive results useful for the future. Above all, the notes on volcano chemistry by Shepherd and Perret demonstrated that engineering apparatus could be applied to the hottest and most continuously active pit in the world. Their success was at the relatively small expense of a journey and a few machines. Brun of Geneva had set an example of similar work, but Perret’s curve of rise and fall added a more detailed record of the Kilauea pit from day to day than had ever been made before.
An observatory is a place of observation and measurement, whether the things observed are glaciers, rivers, stars, the weather, or volcanoes. The motive of observation in modern science is either the quality of what happens or the quantity expressed in lengths and degrees and rates of speed. Remembering the precedent of Vesuvius, I was confronted in Hawaii with the necessity of determining how a volcano should be observed, the need to measure changes in a single volcano, and the need for permanent records of what those changes are. We chose measuring instruments, photographic equipment, and thermometers, and I invented a note-taking system which was compiled into a single record book, from field notes taken uniformly by many different assistants.
7. Volcano House from Observatory, 1913
8. Island in Halemaumau lava lake, 1911. Photo by Perret
