words of particular ballads came long after the transcribing of the
words themselves. There are other elements of perplexity and difficulty
in ballad music which require an expert to unravel and explain, and
which cannot be entered into here. The subject is referred to only
because, in the eyes of the original composers and singers at least, to
dissever the words from the tune would have seemed like parting soul
from body; and because no right notion can be gathered of the Scottish
ballads without bearing in mind the part which the ancient airs have
taken in framing their structure and in moulding their style.

Like the ballads themselves, the 'sets' of ballad airs vary with the
localities; and even in the same district different airs will be found
sung to the same words and different words to the same air. But of many
of the older ballads, at least, it may be affirmed that, from time
immemorial, they have been preserved in a certain musical setting which
has not altered more in transmission from place to place and from
generation to generation than have the ballads themselves, and which has
so wrought itself into the texture and essence of the tale that it is
impossible to think of them apart. The analogy of the Scottish psalmody
may, perhaps, be used in illustration. In it, also, there is a 'common
measure' that can be fitted at will to the common metre--in the psalms,
as in the ballads, the alternation of lines of four and three accented
syllables. In the one case, as in the other, there is a certain family
resemblance, in the melody as in the theme, that to the untrained and
unaccustomed ear may convey an impression of monotony. But to each
ballad, as to each psalm, there belongs a peculiar strain or lilt,
touched, as a rule, with a solemn or piercing pathos, often cast in the
plaintive minor mode, that alone can bring out the full inner meaning
of the words, and that is endeared and hallowed by centuries of
association. As easily might we explain why the words and air of the
'Old Hundredth' or the 'Old 124th' belong to each other, as analyse the
wedded harmony of the verse and music in _The Broom o' the
Cowdenknowes_, or _Barbara Allan_, or _The Bonnie House o' Airlie_.

But not all, and not all the sweetest and the best of our ballad
strains, are so firmly fixed in the memory as these; because, for one
thing, they have not all enjoyed the same popularity of print. As a
rule, and until this popularity comes, it may