The comet that hit Chicago

On our last Amtrak layover in Chicago, last December, Mary and I walked up through the "Miracle Mile" shopping district and saw the ornate municipal water tower that stood alone, surrounded by desolation, after the Great Fire of 1871.

Now comes a suggestion that a comet, not Mrs. O'Leary's cow kicking over the kerosene lantern, might have started the fire. From Discover magazine via Cronaca.

This history of the great fire contains a sentence that the comet hypothesis (multiple impacts=multiple fires) could explain: Before tracing the progress of the fire further northward must be mentioned the burning of the water works, and the curious or rather incomprehensible manner in which it caught fire almost two hours before the time that the fire first reached the north division across the main branch.