I noticed an interesting thing in 47 (St Gall 60, an Irish MS written in about 800. It is on page 60, and consists of a repeated section of text: lines 1-13 are repeated on lines 13-26. The scribe got mixed up with the repeated references to standing at the fire in vv. 18 and 25. There is of course no proof that this was done by the scribe and wasn’t in the exemplar already. But if we work on the basis that such an error was likely to have been screened out quite quickly. Admittedly, there is no sign here that anyone ever spotted a problem, and it’s weird that the section numbers in the margin just ignore the repeat and then carry on. But assuming that this was the scribe’s doing, we have the chance to assess his consistency. This is what I came up with:

A few thoughts:
1. Verse 21 shows a place which the scribe got wrong twice. Hii/hi sciunt is probably intended (isti sciunt 13). Was there a confusing correction or mistake in the exemplar.
2. The layout comes out differently each time, so we can assume that the line lengths in the exemplar were different. Does the superline for m in verse 23 the second time give a hint as to the exemplar’s line break?
3. The rubrication comes out lighter the second time.
4. The punctuation is identical apart from the end of verse 20.
It would be very useful to build up a list of such places, as a way of assessing scribal accuracy. Here in 105 words (taking the repeat with only one ergo in verse 19, we have 6 textual differences, of which 4 are presentational. So there is about one difference in 50 words which might lead to a different form of text in a MS copied from 47.