The four-color ribbon comprises of four inks used in printing: three secondary colors plus black. These ink colors are cyan, magenta and yellow; abbreviated as CMYK. Cyan can be thought of as minus-red, magenta as minus-green, and yellow as…
Slide rule by Frederick Post Company that was sold from approximately 1932-1963. This slide rule is made of bamboo. The slide rule was used to do multiplication, division, trigonometric functions, and logarithms. The straight slide rules were…