Historic Printing Types: A Lecture Read Before the Grolier Club
The pattern
This still is filed under Specimen as proof.
Define
A specimen (type, material, finish) is shown so the product proves itself under comparison.
Mechanism
Controlled display. Same conditions, side by side, no adjective required. The sample is the sentence.
Verdict
Buyers choose by eye or by hand and we can put the real thing in front of them.
Why it works
The marginal sidenotes turn a linear lecture into a scannable reference: a reader can run down the outer edge and find the paragraph he wants without reading the page. Every assertion about a typeface is immediately answered by a facsimile of that typeface set on the same spread, so the evidence is the specimen rather than a description of one. De Vinne sequences the whole piece chronologically and repeatedly uses contrast plates that put two dates next to each other, which makes an abstract stylistic change into something visible in one glance.
Steal this when
Use this structure when you are teaching an audience to notice something they have looked at their whole life without seeing, and the proof is the thing itself. Chronological order plus a margin of scanning labels plus a specimen beside every claim is the right build for any explainer where showing beats describing.