The Italians have a word, _sprofondimento_, which means to make profound by insucking, that expresses what happened. This plexus of uprush of slag and inrush of avalanche, against a water-steam geyser, both happening at once, was very different from the quiet outpouring of lava during the preceding years. It definitely meant rupture of earth blocks, deep escape of that lava probably at the underocean part of the radial cracks, and deep entrance of spring water into incandescent vacated chambers. It meant a rupture crisis, collapsing the peak, and a new geyser quite unrecognized. The eruption ended when the slag pressure was relieved, the mountain blocks had settled, and the frozen slag had shut off groundwater. The remaining lava entered into decades of deep accumulation and gas bubbling, the solfataric phase. That which ended the thirty-year upbuilding was probably downward pressure due to weight of surface heaping of the cone. Cracking released water inward. The next thirty-eight years were to culminate in a similar crisis for Vesuvius which lasted ten days, and again its peak collapsed. This was in March 1944, when our American troops entered Naples. It is interesting that these culminations have been from a third to a half century apart, but the meaning of intervals can only be really understood when volcanoes like Etna, Stromboli, and Vesuvius are grouped together. The same thing is true of Kilauea and Mauna Loa, and of Pelée and St. Vincent. Ponte reports the eruptions of Etna as ten years apart, similar to the sunspot interval; and Perret notes a ten-year interval for the smaller eruptions of Vesuvius. We measured an eleven-year interval for Hawaii, with culminations close to the minimum of sunspots. A culmination is when lava goes down and keeps quiet, or when sunspot numbers go down and remain few. No one knows why, or of any connecting cause. Three eleven-year culminations make a third of a century, when at Kilauea and Vesuvius, something bigger happens. Sunspots have numbered a suspiciously similar curve at corresponding dates. Photographs of Vesuvius taken just before the 1944 collapse showed the 1906 crater hole completely filled and overflowing. There was an inner flat floor, a conelet standing in the middle. The 1944 eruption collapsed the conelet, split the big outer cone, and sent flows to destroy San Sebastiano and several villages. The torrents of ash killed people and the electric station of the funicular railroad was destroyed, as usual. The mountain split in several directions. Just as in 1906, the stages of the 1944 outbreak were lava flows, mixed lava gushing intensely liquid, crateral caving in, tremendous gas emission, black ash changing to vapor and white ash as the emission increased, and ultimately white steam. The black ash was the contemporaneous lava with dark augite; the snowlike white ash was ground up old lavas, containing the white crystals, leucite.