Hooray for Joseph Priestley

Something we never think about: all the little standard things we do were invented by somebody.  I'm not talking about the invention of the printing press.  I'm talking about somebody inventing the shoelace.  Who was the first person who drew an arrow and meant not "this is an arrow" but "go this direction?"  Somebody dreamed that up, but we will never know who.

But we do know about Joseph Priestley.

I am reading Cartographies of Time, by Daniel Rosenberg and Anthony Grafton, about the centuries-long struggle to describe the passage of time visually.  The book is full of illustrations of time as a tree, a circle, a human body, etc. and one is more complicated and confusing than the next.


But in 1765 scientist Joseph Priestley created a variation of what you see above, and called it A Chart of Biography, and suddenly the obscure became clear.  Although the detail is too small to read any modern reader understands what he is showing us.  This is a timeline, with the past on the left, the present on the right and each line marks off a time period, in this case, the lifetimes of great men.  At a glance you can see who were contemporaries, who were in a position to influence each other, etc.  Brilliant.

But you might argue that it only looks intuitive to us because we are used to it.  Not so; the readers in the 1760s immediately understood it and started borrowing, stealing adapting, building from Priestley's invention.

Here's how good an idea this was: twenty-one years later William Playfair published his Commercial and Political Atlas in which he added another dimension to Priestley's work - quite literally.  He tacked on the y-axis, and created line graphs and bar charts. 

Pretty cool.