This song has at least two layers of meaning. It was made famous by the Dubliners and historically has been attributed to Brendan Behan. Behan himself was a prisoner at Mountjoy Jail in Dublin, which is situated on “the banks of the Royal Canal.” The jailers would get the attention of the prisoners through the “jingle-jangle” of an iron bar shaped into a triangle.

Alternately, the “Auld triangle” and “Royal Canal” each have a more… ahem… carnal meaning as well.

Here is a great video with a variety of singers, Irish and otherwise, singing in Royal Albert Hall.

The Auld Triangle

A hungry feeling
Came o’er me stealing
And the mice were squealing
In my prison cell
And that auld triangle went jingle-jangle
All along the banks of the Royal Canal

Oh! To start the morning
The warden bawling
“Get up out of bed, you! And clean out your cell!”
And that auld triangle went jingle-jangle
All along the banks of the Royal Canal

Oh! the screw was peeping
And the (lag|loike) was sleeping
As he lay weeping
For his girl Sal
And that auld triangle went jingle-jangle
All along the banks of the Royal Canal

On a fine Spring evening
The (lag|loike) lay dreaming
And the sea-gulls were wheeling
High above the wall
And that auld triangle went jingle-jangle
All along the banks of the Royal Canal

Oh! the wind was sighing
And the day was dying
As the (lag|loike) lay crying
In his prison cell
And that auld triangle went jingle-bloody-jangle
All along the banks of the Royal Canal

In the women’s prison
There are seventy women
And I wish it was with them
That I did dwell
Then that auld triangle could go jingle-jangle
All along the banks of the Royal Canal