The Annals of Clonmacnoise

Clonmacnoise Monastery was an important place in the Middle Ages. Occupying a major travel route in the center of Ireland, it grew to a community of over a thousand at its height. Besides works of art and religious scholars, it produced a history of Ireland called the Annals of Clonmacnoise (in Irish: Annála Chluain Mhic Nóis).

To be frank, there are no original manuscripts remaining, and there is no firm evidence that it was produced at Clonmacnoise; however, it does focus on the parts of the country around Clonmacnoise—which was a center of learning and production of texts in Irish—and the clans that inhabited them. The Annals contain historical data on O'Kellys, O'Rourkes, O'Molloys, O'Connors, and McDermotts that we would not otherwise have.

The Irish Gaelic of the original was translated into English in 1627 by Conall MacGeoghegan, a descendant of Niall of the Nine Hostages.

This original manuscript, as well as the source from which it came, are both lost, but later edition copies of the translation exist in British and Irish museums. The translator noted that there were sections missing from the manuscript he had found (notably the years 1182-1199 and 1290-1299).

It begins "Adam in the 130 years of his age Begatt Seth, and afterwards Adam Liued 800 yeares & in all he lived 930 yeares." The first page quickly gets to Ireland:

This year of Lamech's age came the woman called Cesarea or Keassar accompanied onely with three men and 50 Women to this land which was the first habitacion of Ireland, though others say that this land was first Discouered and found by three fisher men who were sayleing in these parts of the world, and Because they made noe Residence in the land I will make noe mention of them.

There is scholarly demand for a modern edition to make the information contained available to more researchers.

I'm going to pick one brief entry for further talk. The sole entry for 670 reads "The Moone was turned into a sanguine collor this year." This was likely just a lunar eclipse. Did I say "just"? Lunar eclipses were of special interest to Christians and pagans. Let's talk about them tomorrow.

Gervase and the Moon

Yesterday I mentioned Gervase of Canterbury and his fairly unremarkable life. What follows is the reason he makes an appearance in footnotes in astronomical texts.

Among his other writing duties and pleasures, Gervase also kept the monastery's chronicles, and in 1178 he recorded something interesting:

This year on the 18th of June,[*] when the Moon, a slim crescent, first became visible, a marvelous phenomenon was seen by several men who were watching it. Suddenly, the upper horn of the crescent was split in two. From the mid point of the division, a flaming torch sprang up, spewing out over a considerable distance fire, hot coals and sparks. The body of the Moon which was below, writhed like a wounded snake. This happened a dozen times or more, and when the Moon returned to normal, the whole crescent took on a blackish appearance.

Scholars and astronomers have puzzled over this. Astronomer Jack Hartung in the September 1976 issue of the journal Meteoritics proposed that they had witnessed a meteor strike that created the lunar crater "Giordano Bruno." Recent photos by Apollo made it, in his opinion, a candidate for a young crater only 800 years old. Hartung had his critics, but without new data on the crater, the verdict could rightly claim to be "up in the air." Until years later a student named Paul Withers in Weekly Scientist pointed out an obvious flaw. An impact great enough to create the 14-mile wide Giordano Bruno would have thrown "10 million tons" of debris off the lunar surface; the ejecta in short order would have created unbelievably spectacular meteor showers in Earth's atmosphere. These meteor showers were not noted by monks in England or any other of the sky-gazing cultures that dotted the globe at the time.

So what did the monks see? His guess is that they were looking in the right place at the right time to observe a meteor entering Earth's upper atmosphere between their line of sight and the horns of the crescent moon.

For a modern astrophysicist's view on Gervase' chronicle, see Brian Koberlein's Google + post for today, June 25th, called "Mining for Science."


*N.B. The Proleptic Gregorian Calendar (used for dates prior to 1582 because of a necessary correction) turns this date into June 25th, meaning today is the 834th anniversary of the monks' observation.

Tide Goes In, Tide Goes Out

The Classical World and the Middle Ages wrestled with the cause of the tides for centuries. Although one early scholar (Alpetragius, who flourished in the late 1100s) felt it was caused by some general motion of the world/celestial spheres that ran from east to west, most others (such as Bede and Gerald of Wales) felt it had a stronger connection to the movement of the Moon.
Alpetragius died in 1204, and his theory on the motion that caused the tides was translated into Latin by Michael Scot. This brought it to the attention of Robert Grosseteste (c.1175-1235), who had an explanation for the tides that relied on his theories of light. (The following is from the Questio de fluxu et refluxu maris, attributed to Grosseteste, although that attribution is disputed.)

Remember that there was no working theory of gravity yet; just a feeling that substances could be heavier or lighter depending upon their composition and gravitate (see? in this enlightened age, the concept of gravity pervades even our language) toward like substances: solids fall to earth; liquid (containing more of the element of water) flows to a lower spot to find its kind; fire yearns upward through air, because fire is even "lighter" than air.

For Grosseteste, light imparted force. Rays of light could carry with them the power to generate heat, for instance (see his theory on the sun). He postulated that, when the Moon rose above the horizon, its rays impressed against the waters and pushed them ahead of it, toward the west. This was not as simple and direct as a physical object pushing against water, and so water didn't rush to the shore as soon as the Moon rose. The rays of the Moon started pushing against the sea closest to it, pushing that water toward the observer. When the Moon was overhead, its rays had pushed as much water as it could at that time. Once the Moon passed the zenith and was over land, then the waters started to recede. The Moon then passes west and under the earth, at that point causing (somehow) the tides again.

Grosseteste admits that we don't know everything about this process, and my summary is a radical simplification of his detailed analysis. He notes the changes in tides as the Moon changes its declination, and theorizes that the Sun also "helps" the Moon in some manner.

For more detail, find the Question on the flow and re-flow of the sea (available in Isis, Vol. 57, No. 4 (Winter, 1966), pp. 455-474 in an article by Richard C. Dales) and enjoy.