OK--this is a somewhat truncated version of the material I have. The version in the DT is the same as in Whitelaw, Book of Scottish Song (1844). With slight verbal differences in Ord, Bothy Songs & Ballads (1930), and The Songs of Scotland Chronologically Arranged (2nd ed., n.d.). A 7th verse in George Eyre-Todd, The Glasgow Poets (Paisley, 1906), 166:

Sae rax me your mull, and my nose I will prime,
Let mirth an' sweet innocence employ a' our time;
Nae quarrelling nor fighting we here will admit;
We've parted aye in unity, an' sae will we yet.
And sae will we yet, etc.

There is a text in Gwen Polwarth, Folk Songs of Northumberland (1966), from the Hepple MS., agreeing with Whitelaw & co., save that the burden does not change; the tune there is a *variant* of "The Wearing of the Green".

There is a cousin to this, "Laugh and Be Thankfu'" in the mid-19th century general collection of kailyardery, "Whistle-Binkie" (1890 reprint, I.124), consisting of 5 stanzas, but no tune indicated. Thus: 1: Come sit down 2: nappy guid ale 4: Queen. Others differ as follows.

3: May the taxes come off, that the drink may be cheap,
And the yill be as plentiful as 'gin it were a spate;
May the enemies o' liberty ere lang get a kick;
They've aye gotten't hitherto, and sae shall they yet.

5: Then push round the jorum, an' tak aff your dram,
An' laugh an' be thankfu' as lang as ye can.
For seed-time and harvest ye ever shall get,
When ye fell ye aye got up again, and sae will we yet.

John Greig (Scots Minstrelsie, c. 1895, VI.375) has Sit, farmer, king, glass; and his note (p. xxxiii) says it's a "refinement" of the Whistle-Binkie song, which may indeed be the case.

As for the author: Walter Watson (1780-1854) was one of the many muslin weavers in the village of Chryston, a few miles north of Glasgow. He is called "the Chryston poet", and wrote quite a few songs that became popular. He herded cattle, wound pirns, tried the loom, his father's trade; then a farm labourer, a sawyer in Glasgow, finally (aged 19) was recruited for the Scots Greys (3 years), being discharged at the Peace of Amiens in 1802. Came back to the loom, fell in love, married (1803), and turned to poetry (hampered by an total ignorance of grammar, as the village schoolmaster said). So he studied and became more proficient, and published a collection in 1808. This, like the other editions (1823, 1843) brought him fame but not much else. He spent his last years near Kirkintilloch, where he died of cholera in 1854.

That may be enough for you. I'd be interested to know what the *other* tune of the song is (not, that is, The Wearing of the Green).