Who was William Playfair?
The graph below is a representation of the change in wheat prices from 1565 to 1821. The graph also shows the change in wages of a mechanic relative to the time periods. This graph is the first known bar graph. It shows that as the price of wheat went up, the wages of mechanics also went up. Since these two graphs are shown next to each other, we are lead to belief that their relationship is meaningful or coincidental. All we know is that the wages and wheat prices have some sort of relationship. The audience would have been citizens who are economically concerned since this graphic contains information on wheat prices with respect to wages.
It is also important to note that correlation does not imply causation. While this inforgraphic may be trying to convey a visual image, it does not take basic statistic principles into account. Just because two factors are coincidentally increasing does not mean that once caused the other. Additionally, the pink and green colors aren't identified. What do the two colors event represent? Why do they stand out against they shaded grey colors of the rest of the infographic?
The city skyline is effective as it indicates the time development and visually represesnts the industrial revolution.
The primary visual elements are graphics and handwritten text. The style of handwriting reflects the time period this graph was created. The bar graph is displayed differently than modern bar graphs. Instead of bars that are fully colored or bolded, the bars in this graph fade out at the bottom. The use of lines and numbers play a large role when attempting to read the graph. The lines organize the information and the numbers tell us what we are comparing (prices, years, wages, etc.). The graph may have been more effective if it was more simple and clearer to read. The line at the top of the graph shows who was king at a point in time on the timeline.