…continuedThe Discovery of the Perseid Meteors
A Second Annual Meteor Shower?
Following Olmsted's example, Herrick wrote an article for the January 1838 issue of Silliman's American Journal of Science and Arts in which he proposed the existence of a second annual meteor shower. He listed his evidence and asked for information from anyone else who had seen the display.
While his first article was being published, Herrick turned up four more accounts from other years of meteors plummeting through the skies on August 9th or 10th. He was convinced. "There generally occurs on or about the 9th of August in every year," he wrote, "a remarkably large number of shooting stars."
In a second article Herrick drew further correct conclusions:
Herrick discarded notions that meteors were meteorological, like lightning or rainbows, or debris falling back to Earth after the eruption of a volcano. "Shooting stars are without doubt cosmical or celestial bodies," he wrote, "and not of atmospheric or terrestrial origin." What could that source be? "It is not impossible," Herrick wrote, "that these meteoric showers are derived from nebulous or cometary bodies which, at stated times, the earth falls in." Here was another correct insight, one that Olmsted had broached. The hypothesis that meteors have a cometary origin was confirmed 28 years after Herrick's article, when the connection between meteor and comet orbits was demonstrated.
The August meteors remain near their peak for about three days, and off-peak meteors span perhaps two weeks.
Like those of November, the August meteors have a "starting point," a spot in the sky from which they seem to radiate. Herrick could not yet fix its position among the stars; the meteors were not abundant enough to make their radiant obvious.
The August meteors are more numerous than those of November almost every year, except on rare, overwhelming occasions when the November meteors pour down in torrents.
In addition to November and August, there was probably a third annual meteor shower around April 30th (now called the Lyrids). Herrick found only three cases of it in 1095, 1122, and 1803 but mighty storms of meteors had come in late April of those years.
Pleased with his achievement, Herrick wrote up the new evidence for his annual August shower, included his theories about of meteors, and gave the paper to Silliman for publication in his journal. Less than two weeks later Herrick received crushing news. He was not the shower's discoverer after all.