To spot accountants back in the the good old days of hand-operated calculating and adding machines was easy: you just looked out for well-developed right-arm biceps - see above - and which is why there are no left-handeded accountants!
There was the Odhner manual calculator with an external moving carriage, and the Facit machine which reversed this arrangement with the carriage fixed but the rotor moving. Both came with extensive manuals but everyone seemed to learn on the job how to use them.
Adding machines were similarly hand-operated, with larger accounting firms employing specially trained "comptometrists" to operate these machines, unfortunately making it more difficult to spot accountants.
Mind you, you would never have spotted me as an accountant, as my right arm has always been just as thin as my left one - to this day!
