Apropos of the recent metoric [sic] showers and the explosion of steam boilers in every part of the country, Professor Loomis suggests an uncomfortable theory in regard to the safety of the earth itself. He thinks it is not impossible that sufficient steam might be generated in the burning centre of the world to blow the world to pieces. A volcanic eruption under the sea, or near it, like that of Vesuvius now in progress, may at any moment convert the earth into a huge steam-boiler by letting the water in upon the central fires, to be followed for ought we know, by an explosion that shall rend it apart and send the fragments careening through space as small planets or meteors, each bearing off some distracted member or members of the human family, to make, perchance, new discoveries and acquaintances in other parts of the planetary system now revolving with us. So that the final catastrophe may, after all, be only a boiler explosion on a magnificent scale of grandeur and destruction.
According to the eruption list, Vesuvius was erupting from 1864 to 1868.
Elias Loomis (1811-1899) was a prolific scientist and textbook author who measured the earth’s magnetic field, studied auroras, and did a lot of meteorology. He was an early professor at my alma mater, building one of the earliest and largest observatories in the American West (at that time, that meant Ohio). The building, at least still stands (as far as I can tell) on the campus of the prep school which remained in Hudson when Western Reserve College moved to Cleveland.
But in the several bits of biography I’ve seen on the web, nothing mentions him describing the likelihood of the earth blowing up in a puff of steam.