Grandes constructions de quelques anciens peuples
The pattern
This still is filed under Data as proof.
Define
A chart, map, or count that is the argument, not an illustration next to the argument.
Mechanism
Sighted evidence. The reader is asked to believe their eyes: a bar, a share, a spread on a map.
Verdict
The claim is comparative or quantitative and the figure can be read without a caption doing the sell.
Why it works
One declared scale across both panels means the comparison the title promises is made by the eye and needs no sentence to carry it. Minard shows the working rather than hiding it: the nota admits that Grobert never gave the height of the first course, states the assumption used in its place, and sets the arithmetic column beside the drawing it produced, so a sceptical reader can audit the figure instead of trusting it. Splitting the sheet into two ruled panels forces the comparison while letting each subject keep its own units and figures intact.
Steal this when
When a claim rests on someone else's measurement and that measurement has a hole in it, print the source, the gap and the substituted assumption next to the drawing rather than quietly smoothing it over. Right for any technical comparison an expert reader will try to break.