Thursday’s ad is for Guinness, from 1955. The ad features Scottish writer Robert Louis Stevenson, who was born today in 1850. R.L.S. — as he’s referred to in the tagline — was the author of “Treasure Island,” the “Strange Case of Dr Jekyll and Mr Hyde,” and many others. According to the ad, which ran in the Illustrated London News, Stevenson was aboard a cruise ship in the South Pacific in 1893, when he wrote a letter to a person named Colvin, a portion of which was also part of the ad copy:

Fanny ate a whole fowl for breakfast, to say nothing of a tower of hot cakes. Belle and I floored another hen betwixt the pair of us, and I shall no sooner be done with the present amanuensing racket than I shall put myself outside a pint of Guinness. If you think this looks like dying of consumption in Apia, I can only say I differ from you.