Comets have been considered in all times and in all countries as signs, precursors of fatal events –Antiquity and universality of this belief; its probable origin- Opinion of Seneca ; habitual and regular phenomena fail to attract the attention of the multitude; meteors and comets, on the contrary, make a profound impression – The moderns in this respect resemble the ancients contemporary with Seneca –The incorruptible heavens of the ancients, in contradistinction to the sublunary or atmospheric regions; stars and meteors –Inevitable confusion of certain celestial or cosmical phenomena with atmospheric meteors.

In all countries and in all times the apparition of a comet has been onsidered as a presage: a presage fortunate or unfortunate according to the circumstances, the popular state of mind, the prevailing degree of superstition, the imbecility of princes or the calculation of courtiers. Science itself has helped to confirm the formidable and terrible signification most frequently accorded by common belief to the sudden and unexpected arrival of one of these remarkable stars. Not two centuries ago, as we shall shortly see, learned men and astronomers of undoubted merit continued to believe in the influence of comets over human events. What wonder, then, if we should find existing in our own time, in the midst of the nineteenth century, numerous vestiges of a superstition as old as the world?