Keuffel & Esser Polyphase Slide Rule with Case and Instruction Manual Valentine - FOUR small mid century

- FOUR small mid century modern trays (as shown)

There are some Shiny Brights

The fabric is discolored showing spots and stains

The main message reads: 'To My Valentine'

Keuffel & Esser Polyphase Slide Rule with Case and Instruction Manual Valentine - FOUR small mid centuryBefore computers, slide rules were IMPORTANT tools. Today, they are relics of the past. However, this Keuffel & Esser polyphase slide rule is not a relic. Instead, it's a peek into the greatest math minds from yesterday. A look at the history of mathematics and how slide rules were used by engineers and scientists before computers were in every household. A great gift for the math nerd (or math genius) in your life. Listing Includes ONE vintage