According to Humboldt, Chladni states that a Franciscan monk was killed by the fall of an aërolite at Milan in the year 1660.[247] Humboldt also mentions the death by meteoric stones of a monk at Crema on September 4, 1511, and two Swedish sailors on board ship in 1674.[248] It is a curious fact that, according to Olbers, "no fossil meteoric stones" have ever been discovered.[249] Considering the number which are supposed to have fallen to the earth in the course of ages, this fact seems a remarkable one. On May 10, 1879, a shower of meteorites fell at Eitherville, Iowa (U.S.A.). Some of the fragments found weighed 437, 170, 92½, 28, 10½, 4 and 2 lbs. in weight. In the following year (1880) when the prairie grass had been consumed by a fire, about "5000 pieces were found from the size of a pin to a pound in weight."[250] According to Prof. Silvestria of Catania, a shower of meteoric dust mixed with rain fell on the night of March 29, 1880. The dust contained a large proportion of iron in the metallic state. In size the particles varied from a tenth to a hundredth of a millimetre.[251] It is sometimes stated that the average mass of a "shooting star" is only a few grains. But from comparisons with an electric arc light, Prof. W. H. Pickering concludes that a meteor as bright as a third magnitude star, composed of iron or stone, would probably have a diameter of 6 or 7 inches. An average bright fireball would perhaps measure 5 or 6 feet in diameter.[252] In the Book of Joshua we are told "that the LORD cast down great stones from heaven upon them unto Azekah, and they died" (Joshua x. 11). In the latter portion of the verse "hailstones" are mentioned, but as the original Hebrew word means stones in general (not hailstones), it seems very probable that the stones referred to were aërolites.[253] The stone mentioned in the Acts of the Apostles, from which was found "the _image_ which fell down from Jupiter" (Acts xix. 35), was evidently a meteoric stone.[253] The famous stone in the Caaba at Mecca, is probably a stone of meteoric origin.[253] I "Stones from Heaven! Can you wonder, You who scrutinize the Earth, At the love and veneration They received before the birth Of our scientific methods? II "Stones from Heaven! we can handle Fragments fallen from realms of Space; Oh! the marvel and the mystery, Could we understand their place In the scheme of things created! III "Stones from Heaven! With a mighty Comet whirling formed they part? Fell they from their lofty station Like a brilliant fiery dart, Hurl'd from starry fields of Night?"[254] CHAPTER XIII The Zodiacal Light and Gegenschein