Siena, 1794: History's Most Consequential Meteorite Fall
Abstract
In the mythos of meteoritics, the fall of stones at L'Aigle in Normandy at 1 p. m. on April 26, 1803, is commonly regarded as the event that turned skeptics into believers and opened the way for the new science. A strong case can be made, however, that the fall of stones at Siena at 7:00 p.m. on June 16, 1794, established the authenticity of meteorite falls and set in motion the reexaminations of entrenched beliefs that led to the founding of the new science. The Siena fall was heralded by the appearance of an extraordinarily high, dark cloud emitting smoke, sparks like rockets, and bolts of unusually slow-moving red lightning. With a tremendous explosion a shower of stones, ranging in weight from a few milligrams to 3 kg, fell southeast of Siena. This was the first meteorite fall to occur in the vicinity of a sizeable European city and the first to be witnessed by so many people, including English visitors, that the fall of the stones from the sky could not be denied. It also was the first fall to be seriously investigated by scholars, at several universities in Italy, who collected eye-witness reports and specimens and formulated hypotheses of origin. Their task was greatly complicated by the timing of the fall which occurred 18 hours after Mt. Vesuvius sprang into full eruption. Some believed that the two events were entirely coincidental; others thought that the stones either were ejecta from the volcano (which lay about 320 km to the southeast of Siena) or had consolidated in the fiery masses of dust and ash expelled by the mountain. No explanations seemed entirely satisfactory, but, in an age when the very possibility of falling stones had been decisively ruled out by savants of the Enlightenment, the well-observed fall at Siena opened a new dialog on this subject. The Siena fall occurred only two months after the publication in Riga and Leipzig of Ernst F. F. Chladni's book On the Origin of Ironmasses in which he concluded from historical records that fragments of iron and stone fall do, indeed, fall from sky. News traveled so slowly in the 18th century that Chladni's book received negative reviews in Germany throughout 1794 and much of 1795 before the first notice of the Siena fall appeared in a Berlin paper in 1796. The same amount of time passed before Chladni's book reached England, but the groundwork for a more tolerant reception of it in that country was laid by travelers returning from Italy in 1794 with their descriptions and their specimens from Siena (including bogus "fallen stones" fabricated for the tourist market). Widespread interest was aroused in 1795 when the Royal Society published an account of the eruption of Mt. Vesuvius by Sir William Hamilton, the English Ambassador at Naples, who included a short discussion of the Siena stones and their possible link with the volcano. Hamilton's article carried the story of the Siena fall to France and Germany. The case for fallen stones was further strengthened when a 56-pound stone fell at 3:30 p.m. on December 13th, 1795, at Wold Cottage in Yorkshire. Early in 1796, Edward King, a Fellow of the Royal Society, published the first book in English on fallen stones. In it, he focused primarily on the Siena event but just as he was finishing his text he received a copy of Chladni's book and quoted from it extensively. King's 36-page book was widely read. It received some bad reviews in England but it immediately prompted one reader to report the fall of a stone [apparently a genuine meteorite] at Pettiswood, Ireland. He had withheld his story for 17 years for fear of ridicule. Now, the climate of opinion had changed and meteoritics already was becoming a new branch of science.
- Publication:
-
Meteoritics
- Pub Date:
- September 1995
- Bibcode:
- 1995Metic..30R.540M
- Keywords:
-
- CHLADNI;
- ERNST F. F.;
- HAMILTON;
- WILLIAM;
- KING;
- EDWARD;
- L'AIGLE;
- PETTISWOOD;
- SIENA;
- WOLD COTTAGE