I just had reason to have a look at the words of Robert Burns' song My luve is like a Red Red Rose, and discovered to my surprise that one of the lines in it that I most like isn't evidently in the accepted version.

The first verse as given in the Digital Tradition, and generally, ends

.O my love is like a melodie,
that's sweetly play'd in tune.

And yet as I've always known it it's

'My luve is like some instrument
So newly set in tune

Which has always struck me, as a guitarist, as a particularly apt simile.

So where does it come from? Is it a variant Burn used which has slipped out of use? If I thought I'd made it up myself I'd be quite proud of myself, but I don't think I did. But hunting round on the Internet I can't find any trace of it.