Why is the R used for the ideal gas constant? What does R stand for? Who came up with R?

Since I have no idea what the real answer is, I'll go with what I do best. Make **** up.

The R is remnant of historical physics. Back in the early days, when gun powder was plentiful and cannons were a means to defend ships, people had to figure out what happened with expansion of gasses when powder was lit. They came up with rough equations, and originally started at the beginning of the alphabit with variables. It was the thieves and pirates who popularized the equations, though, through misunderstanding. When the A was present at the beginning, they just couldn't help themselves from adding a few letters. Thus, today, the gas constant:

Arrrrrrrrr.

Which letter would you rather use?

This is the kind of stuff that drives me crazy as well! I went in search of the answer some time ago, so I'll share what I found out. As usual, the answer relates to a history lesson. It was Clausius in the mid 1800's that refined the conversion factor for converting degrees Celsius to Kelvins (from adding 267 to adding 273 to the Celsius temperature. He did so using the careful experimental data of another French scientist, Regnault. Clausius also noted that Regnault's data indicated that the farther the temperature and pressure conditions were from the condensation point of the gas, the more correctly the Ideal Gas Law applies. In the spirit of giving credit where credit is due, my source was a Journal of Chem. Ed article written by William B. Jensen
Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172