I haven't tried to re post others quotes. But here goes. This is a slide rule. I had one in high school and used it to calculate percentages for grades when I was a teacher until they came out with hand held calculators. You can multiply and divide and do logarithms to add and subtract. It can also be used for doing more complicated operations but I stayed with multiplying and dividing. We also had a book of logarithms. I lost mine, and I miss it.
it works by sliding the the number on the movable bar over one and then moving the clear plastic until the line comes over the number on the bottom slide and the answer is on the top. 6 over the one times two on the bottom of the slide rule under the line on the clear plastic slide should equal 8 which is above that number. Or something like that. Its been over thirty years since I had one so I probably have it wrong. You might try the link below to find out for sure.
http://sliderulemuseum.com/SR_Course.htm
