Statistical Atlas of the United States, Based Upon the Results of the Eleventh Census (1890) - plate 14: Density of population in detail
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
The method paragraph is placed before any of the narrative, so the reader inherits the definitions before forming conclusions, which is what makes the later decade-by-decade claims land as fact rather than interpretation. Naming the arbitrary choices out loud, the city cut-off, the assumption of uniform distribution over a county, the subdivision of oversized western counties, converts potential attacks into disclosed limitations. The decade sections follow one fixed shape, first where settlement moved, then what changed in territory, so ten paragraphs stay navigable without a single subhead. The two closing tables convert the whole narrative into two numbers a reader can quote, and the line about the frontier line ending is left bare with no elaboration, which is why it is the sentence everyone remembers.
Steal this when
Use this when a set of visuals will be argued over and you need the methodology to travel with them: a benchmark study, a scoring model, an index, a market map. Write the definitions and the arbitrary cut-offs first in plain prose, run the narrative in one repeated shape, and close with a small table that lets someone quote you correctly.