Yesterday, I was curious about the history of graphs and found that William   
   Playfair was the first to use graphs to plot data. https://en.wi   
   ipedia.org/wiki/William_Playfair   
   He is credited in inventing bar graphs among other types.   
   I suspect that Rene Descarte used graphs to draw mathematical functions, but I   
   don't know if he was the first (Anybody know?). Euler is the father of   
   graphical theory.   
   In my searches I found the question What is the origin of the graph? The   
   answer is X=0, Y=0. Not exactly what I was looking for.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)