“The oxygen of the air would prove insufficient to maintain the combustion, but there is another gas which physicists do not often think of, for the simple reason that they have never found it in their analyses—hydrogen. What has become of all the hydrogen freed from the soil these millions of years which have elapsed since prehistoric times? The density of this gas being one-sixteenth that of the air, it must have ascended, forming a highly rarified hydrogen envelope above our atmosphere. In virtue of the law of diffusion of gases, a large part of this hydrogen would become mixed with the atmosphere, but the upper air layers must contain a considerable portion of it. There, doubtless, at an elevation of more than one hundred kilometers, the shooting stars take fire, and the aurora borealis is lighted. Notice here that the oxygen of the air would furnish the carbon of the comet ample material during collision to feed the celestial fire. “Thus the destruction of the world will result from the combustion of the atmosphere. For about seven hours—probably a little longer, as the resistance to the comet cannot be neglected—there will be a continuous transformation of motion into a heat. The hydrogen and the oxygen, combining with the carbon of the comet, will take fire. The temperature of the air will be raised several hundred degrees; woods, gardens, plants, forests, habitations, edifices, cities, villages, will all be rapidly consumed; the sea, the lakes and the rivers will begin to boil; men and animals, enveloped in the hot breath of the comet, will die asphyxiated before they are burned, their gasping lungs inhaling only flame. Every corpse will be almost immediately carbonized, reduced to ashes, and in this vast celestial furnace only the heart-rending voice of the trumpet of the indestructible angel of the Apocalypse will be heard, proclaiming from the sky, like a funeral knell, the antique death-song: ‘Solvet sæculum in favilla.’ This is what may happen if a comet like that of 1811 collides with the earth.” At these words the cardinal-archbishop rose from his seat and begged to be heard. The astronomer, perceiving him, bowed with a courtly grace and seemed to await the reply of his eminence. “I do not desire,” said the latter, “to interrupt the honorable speaker, but if science announces that the drama of the end of the world is to be ushered in by the destruction of the heavens by fire, I cannot refrain from saying that this has always been the universal belief of the church. ‘The heavens,’ says St. Peter, ‘shall pass away with a great noise, and the elements shall meet with fervent heat, the earth also and the works that are therein shall be burned up.’ St. Paul affirms also its renovation by fire, and we repeat daily at mass his words: ‘Eum qui venturus est judicare vivos et mortuos et sæculum per ignem.’”