In the Days of the Comet is a science fiction novel by H. G. Wells in which humanity is ‘exalted’ when a comet causes ‘the nitrogen of the air, the old azote, ‘ to ‘change out of itself’ and become ‘a respirable gas, differing indeed from oxygen, but helping and sustaining its action, a bath of strength and healing for nerve and brain.’ The result: ‘The great Change has come for evermore, happiness and beauty are our atmosphere, there is peace on earth and good will to all men.’