The Stones That Fell at L'Aigle

Summary

In the early afternoon of 26 April 1803 about 3,000 stones fell out of a clear sky around L'Aigle in Normandy. The French government sent the 29-year-old Jean-Baptiste Biot to investigate, and his report persuaded the last sceptics that stones really do fall from the sky.

The fall is often told as the day science discovered meteorites. The record is more interesting. Ernst Chladni had argued in 1794 that stones and masses of iron fall from space, and chemical analyses published in London in February 1802 had already convinced leading scientists that such falls were real. L'Aigle finished the argument about whether stones fall. It did not settle where they come from. Biot himself favoured volcanoes on the Moon, and the question stayed open until the 1950s.

What is documented

The fall. It happened on Tuesday 26 April 1803, 6 floréal year XI in the French Republican calendar, in the early afternoon and from a clear sky (Mitton, 2021). Stones came down over the country around the town of L'Aigle, in the department of the Orne. Ursula Marvin, in her history of Chladni's work, puts the number at nearly 3,000; Arizona State University's Center for Meteorite Studies says over 3,000. Mitton gives the total mass as 37 kilograms.

The investigation. The Minister of the Interior, Jean-Antoine Chaptal, himself a scientist, ordered Biot to confirm the report (Crosland; Gounelle, 2003). Biot was 29. He took a compass, a 1:86,400 map of the area and a sample of the stone that had fallen at Barbotan in 1790 (Gounelle, 2003). He questioned people across the district, compared the stones with the ground they had been taken from, and had some of them analysed chemically (Crosland).

The report. Biot read his report to the First Class of the Institut national in July 1803, and it was printed the same year. Crosland gives the day as 18 July. Gounelle gives it as 29 messidor year XI, which he converts to 17 July, but 29 messidor year XI fell on 18 July. According to Gounelle's account, Biot set out two kinds of evidence. The physical evidence was that no stones of this kind had been known in the district before, that identical stones had suddenly appeared, and that they resembled stones from other falls. The moral evidence was the number of witnesses, from varied social classes, who had seen "a rain of stones thrown by the meteor". Biot presented himself as a witness foreign to any system. Crosland writes that the report "marks the beginning of a general recognition in France of the reality of meteorites."

Before L'Aigle. In 1794 Chladni published a 63-page book, Über den Ursprung der von Pallas gefundenen und anderer ihr ähnlicher Eisenmassen, proposing that stones and iron masses enter the atmosphere from cosmic space and form fireballs as they fall. Marvin (1996) notes that this broke two strongly held beliefs: that rock and metal do not fall from the sky, and that no small bodies exist in space beyond the Moon. He was criticised for relying on historical eyewitness reports that others regarded as folk tales. Between 1794 and 1798 four falls of stones were witnessed and widely publicised. Then the chemist Edward Howard and the mineralogist Jacques-Louis de Bournon showed that the fallen stones were much alike in texture and composition, and different from the Earth's known crustal rocks. Howard found nickel both in the "native irons" and in the metal grains of the stones, linking the two. Marvin writes that these results, published in February 1802, persuaded leading scientists in England, France and Germany that bodies fall from the sky, that French chemists reported similar results within months, and that opposition lingered until April 1803.

After L'Aigle. Chladni was immediately credited with the hypothesis of falls. His link between falling stones and fireballs took decades to be generally accepted, and his cosmic origin met strong resistance (Marvin, 1996). Some argued that the stones formed in the atmosphere; others, Biot among them (Gounelle, 2003), that they were thrown out by volcanoes on the Moon. Marvin records that both ideas were abandoned after 1860, that a century of argument followed over whether meteorites came from between the stars or from within the solar system, and that conclusive evidence of their elliptical orbits established their parent bodies as members of the solar system only in the 1950s.

The stones. L'Aigle is classified as an L6 chondrite, an ordinary chondrite (Arizona State University).

Leading explanations

A meteorite shower from a body in the solar system. Established. The stones are meteorites of a common class, L6 chondrite. That meteorites fall was accepted in 1802 and 1803. That they come from parent bodies orbiting the Sun was established, in Marvin's account, by orbital evidence in the 1950s. There is no competing explanation of the L'Aigle fall.

Formation in the atmosphere. Abandoned after 1860. The idea that the stones formed within the Earth's atmosphere was one of the two leading alternatives to Chladni's cosmic origin after 1803 (Marvin, 1996).

Ejection by volcanoes on the Moon. Abandoned after 1860. Biot's own preferred origin (Gounelle, 2003), and the other leading alternative. Marvin dates its abandonment to after 1860.

Current status

Later explained. The fall is among the best documented of its era: a government-ordered field inquiry, dozens of witnesses questioned, chemical analyses, and a report to the national scientific body within three months. The stones are an ordinary L6 chondrite, and the explanation, a meteorite shower from a parent body in the solar system, is established. In 2024 Marsset and colleagues argued in Nature that the L chondrites, the most abundant class of meteorite falling on Earth today, come from the Massalia asteroid family in the inner asteroid belt.

The detail that remains uncertain is a small one: the exact count of stones, which sources give as nearly 3,000 or over 3,000. It does not affect the case. The registry keeps it for what it shows about how the change happened: a hypothesis in 1794, witnessed falls, a chemical signature in 1802, and then a fall so large and so well witnessed that it won over the last sceptics.

Last reviewed: September 2026. Records are provisional. Where the evidence changes, the entry changes. Found an error? Tell us.