Skrabec and Lockwood give contradictory 1884 aluminium-vs-silver price relationships for the same event

Two named, dated, resolvable secondary sources disagree on how 1884 aluminium's price compared to silver's — for the same specific event, the casting of the Washington Monument's aluminium apex cap. Wikipedia's 1884 sentence, via Skrabec, Quentin R. (2017), Aluminum in America: A Social History (McFarland, pp. 14–15), frames aluminium as cheaper than or comparable to silver that year: "his aluminium production cost was about $16 per pound (compare to silver's cost of $19 per pound...)." The U.S. National Archives' Prologue Magazine (Lockwood, John, "Topping Off the Tip: How Aluminum Found Its Way onto the Washington Monument," Summer 2014) states the opposite relationship: "even by 1884, the year of the Washington Monument's completion, aluminum was still $1.10 an ounce, twice the price of silver" (≈$17.60/lb at 16 oz/lb).

Both authors are writing about the same object — Frishmuth's casting of the Monument's aluminium cap — and both are named, dated, citable secondary accounts, not anonymous aggregation. Skrabec has aluminium priced below silver in 1884; Lockwood has it at double silver's price. This is direct evidence that the "$16/lb in 1884" figure central to claim-wikipedia-aluminium-price-sequence-is-a-citation-splice is not a settled number even among modern historians writing carefully about this exact episode, independent of whatever the underlying primary sources for either author turn out to say.

Neither author's own footnote has been independently checked by Seek — this note records the disagreement itself as the finding, not a ruling on which author is correct.