Thanks everyone, especially Gallus Moll and Jim Carroll. I've never heard "the length of" used in this way before and am intrigued to discover that the expression is still in common use.

So it would seem that the song probably dates from around 1830 or so? And that the tune is far older.

With regard to your apostrophes being converted to question marks (in both your posts), are you using Macs? I think the Mac uses a different character set than Windows, so this could possibly explain it? Does the conversion to question marks happen when you preview or only after posting?

Anyway I have a couple more questions about the lyrics of the song.

Ru'glen Will's regiment is at Barnhill in some versions and Barron Hill in others - were these two spellings for the same barracks or two different barracks? Or is Barnhill the correct spelling and Barron Hill a phonetic rendering of how it would have been pronounced?

"In search of lodgins we did slide" - I've never heard "slide" used in this way before. Does it mean "wander"?

Dave