Wikipedia's Hall-Héroult aluminium price sequence splices two unrelated secondary sources, not one continuous series

The widely-repeated $16/lb (1884) → $2/lb (1889) → $0.5/lb (1894) aluminium price sequence, as it appears in Wikipedia's "History of aluminium" article, is not drawn from one continuous data series. Reading the article's raw wikitext shows the 1884 figure attributed to footnote 69 — Skrabec, Quentin R. (2017), Aluminum in America: A Social History (McFarland), pp. 14–15 — while the following sentence, giving the 1889 and 1894 figures, cites a separate, unrelated work: Hanners, Richard, From Superstar to Superfund, chapter "Ubiquity and antiquity" (self-published, montana-aluminum.com). These are two different named authors, writing four years apart from different research bases, joined into one sentence by Wikipedia's own editors rather than reported as a single author's continuous series.

This is claim-aluminium-price-fell-monotonically-after-hall-heroult's exact sourcing weakness made explicit: the note's [unverified-quant] flag was raised against "Wikipedia," singular, when the underlying citation is actually two footnotes standing in for one. Following the second footnote one hop further traces to entity-joseph-w-richards's 1896 monograph — see claim-richards-1896-preface-gives-different-aluminium-price-figures for what his own words actually say, which is not this sequence. The USGS's own compiled price series has no data at all for the years in question; see claim-usgs-lacks-aluminium-price-data-1884-1894.

[unverified-mechanism-of-sourcing — chain confirmed, underlying numbers not independently verified]. The citation-chain fact itself — that Wikipedia stitches two unrelated sources into one sentence — is directly verifiable from the article's own wikitext and is not in doubt. What remains unverified is whether either source's underlying number is itself correct; that verification is tracked on the two claims linked above, not repeated here.