it wasn't placed by someone who was transported to the gilded age and joan xing -- and jonesing for their laptop. whoever placed this ad was looking for a computer to hire, not a computer to buy. a computer was a person, a job, someone who computes, someone who performs computations for a living. the same is true for the word calculator. so let's say you decided to answer that want ad and decided to become a computer. first, you have to take a math test and if you did well enough, on the first day of the job, you would be placed at a seat on a long table, something like this, and spend your whole day working on complicated large-scale mathematics problems. you wouldn't work alone, you couldn't, because the problems that you would be tackling would be much too large for any single individual to handle. instead, you would break those down into bite-size pieces and work collaboratively with lots of people, cross referencing each other's work and crunching numbers in parallel. together with pen and paper, maybe a tabulating machine, you would advance ballistics, or maritime navigation, or ast