What is the Etymology of that Idiom?

I always find it interesting to learn the origins of old sayings and yesterday discovered the following while reading about Tyburn, the site of public executions for nearly 600 years in London, I read that following hangings of particularly notorious or significant 'criminals' the hang man would cut up the hanging rope into sections and sell it, hence the saying 'Money for Old Rope'.

Apparently the condemned would also be taken to a public house on route from their place of incarceration to the gallows and permitted one last alcoholic drink. After that they were returned to the wagon carrying them to their doom, never to drink again, hence the sayings 'Fallen off the Wagon' or 'Back on the Wagon' referring to drinking or abstaining from drink. 

While very interesting I did find the subject matter quite horrific. I do not believe in the death penalty and historically we have been particularly barbaric in its delivery, as such rather than use an associated image to support this post I have chosen a picture of Data, a character from Star Trek The Next Generation. The subject line for this post is taken from his script during an episode where he first heard the phrase 'Burning the Midnight Oil'. 

Image Credit: Pinterest