cool website of the day: vintagecalculators.com

i own a vintage mechanical calculator- an addiator arithma. (the technical term, i have learned, is "slide adder") i'm not quite sure how old it is, but it belonged to my grampa. i'm guessing 1960's. i wish mine had a slide rule on the back like some of the ones on this site. that would make it extra nifty!

after some more googling, i see that it was produced in 1962 and cost 5 dollars. on ebay, you can get one just like mine for between 5 and 20 bucks.