The pix, above, date back to the original US invention by Philip Dalton in the early 1930s. Later innovations saw the introduction of a much more easily useable slide version. The CR dates back to Siegfried Knemeyer's dreieckrechner, also in the early 30s, but on the other side of the WW2 table.
Am I a dinosaur - I still use my Dalton slide computer regularly ? A lot quicker and easier than the CR for a lot of stuff. With the few which have compressibility corrections included, who needs a CR ? Having said that, I use both.