We have been treating line (b) of stanza 4 as follows:
(b) Ad-chíu leas o luagh
However, on having another look at the MS, I noticed that the 'o' in
front of 'luagh' looks rather doubtful. It is way too big and has a
horizontal stroke at the bottom.
What we have, I think, is the numeral '2'. This was used as a scribal
contraction to stand for 'dá'.
I would now read:
4. Dréacht a Cholum chaigh (= chaidh)
Ad-chíu leas dá luagh
a chnáimh coire ar cúl
ba dán oile úan.
A selection [of verse] by Holy Colum [i.e Colum Cille],
I see a benefit from its recompense;
its ‘cauldron bone’ in return
should be another poem from us.