Playfair also began creating the circle pie chart to show the part/whole relationship in 1801, but this particular chart did not become popular until Florence Nightingale (1820–1910), the founder of modern nursing, began using it more frequently in 1857 in the form of a polar area diagram, or similar to a radial histogram. Nightingale’s “Rose diagram” was used to explain patient mortality in the military field hospital she managed during a specific year. A copy of that chart was sent to Queen Victoria the following year. Refer to Figure 1-11 and Figure 1-12. Figure 1-11.  Pictorial timeline of 1801–1900 AD Figure 1-12.  Pictorial sketch of Playfair with his pie chart…