Wilson’s determination of heights above sea level certified that the whole mountain swelled up during the ten years prior to 1921. About 1918, lava and seismographs had proved rising overflow at the center, while the edge of Kilauea Crater was being tilted away from the center. This went on during the massive rising of the interior lava of Halemaumau into a dome where the pit had been, and it proved that Kilauea Mountain was being injected along cracks, not only under the pit, but along the rifts, as indicated by outflow on the southwest and east in the years 1920 and 1924. But this was not all of Wilson’s work. He revisited all surveying stations after the big collapse of Halemaumau that accompanied the explosive eruption of May 1924, and found that the Volcano House benchmark lowered a little more than three feet during May 1924 and that places close to Halemaumau dropped nearly fifteen feet. This lowering of the mountain was graduated outward twenty miles from the center at trig stations, or concrete posts, in the Kau Desert and at stations along the road to Hilo. These stations changed altitude to show that the big mountain tumefied or swelled up to that distance of twenty miles during the big intrusion of cracks at the overflowing time, as though the mountain dome were a tumor forty miles in diameter with Halemaumau at the center. Of course there is no certainty that the shore line in Puna, or even the Hilo tide gauge itself, did not go down with the slumping of the mountain, for the thing called sea level is nothing but an average of tide gauge readings at a fixed wharf. Remember that the east point of Hawaii sank eight feet on the Kilauea rift during the April crisis. Wilson also surveyed by horizontal triangulation in 1921, determining that stations around Halemaumau had moved inward toward the center, by a specified number of feet, different at each station, and that other stations outside of Kilauea Crater had changed position horizontally on the map, as though the mountain were shrinking. This entire series of measurements of change between 1911 and 1926 jibed with the seismograph’s measurements of the tilting of the ground. The seismograph picked out 1918, when Halemaumau overflowed, as the swelling year. In 1924 the tilt reversed itself, turning inward toward Halemaumau, and became tremendous when the pit collapsed and exploded.