I was unable to go to Hawaii until 1912, so I was delighted when Perret consented to go to Kilauea Volcano in company with E. S. Shepherd, gas chemist of the Carnegie Geophysical Laboratory of Washington, in the summer of 1911. Dr. A. L. Day, director of the Carnegie laboratory, kindly supplied at our expense two Leeds and Northrop resistance pyrometers and the accompanying Wheatstone bridge, as well as thermocouples loaned from his equipment. Perret and Shepherd went to Kilauea Volcano House; and Perret built a hut at the edge of Halemaumau pit, where an inner lava lake was bubbling and maintaining an island some 200 feet below the rim. Kilauea is the big cauldron, Halemaumau is the firepit in its floor. “Kilauea” activity generally means Halemaumau. They have separate cliff margins. L. A. Thurston, leading journalist and publicist of Hawaii and keen promoter of a proposed Hawaii National Park, did everything possible to help the scientists. Perret wrote weekly reports on the condition of Halemaumau lava, and sent in photographs to Mr. Thurston’s newspaper, the _Pacific Commercial Advertiser_. Living and camping at the fire pit, Perret inaugurated something new for Hawaii, and set a standard for the Volcano Observatory. These continuous reports had been my dream for such volcanoes as Vesuvius, where publication had usually been in delayed annuals and gave no current news of what the volcano was doing. Furthermore, the Vesuvius observatory was at the foot of the peak. I had ordered from the Lidgerwood Company an equipment of cables, including some containing electric wires. These were to span the 1,500 feet and to lower a thermometer into the pit of Halemaumau. Assisted by Alex Lancaster, the active little half-breed guide from Virginia, and by numerous laborers from the plantations, whose managers, spurred on by Thurston, took a great interest in the project, Perret and Shepherd erected two high A-frames on opposite sides of the fire pit and built a trolley on the cable stretched between them. Perret kept constant angular measurement of the changing height of the liquid lava, as the glowing slaggy pool rose and fell overflowing its banks. At one side of a triangular island was a point of ebullition called “Old Faithful” where gas bubbles burst in a fiery dome, irregularly, but approximately once a minute. The objective was to find the temperature of the liquid lava in the vicinity of the bubbling. This was achieved by actually dipping the electric pyrometers into the molten slag, then observing the precise temperature at the recording box, which was in the hands of Dr. Shepherd, who remained on the pit rim at the upper end of the connecting wires.