In The Substitution of Similars (1869) Jevons derives the logical slate, abacus, and machine directly from 'this process of indirect inference' — the same elimination principle his Chrysippus quotation illustrates, but without re-naming Chrysippus

jevonslogic-machinesdisjunctive-syllogismreasoning-by-eliminationhistory-of-computingindirect-inferencesubstitution-of-similars

In The Substitution of Similars (1869) — published the same year the Logic Piano was built — William Stanley Jevons walks without a seam from a restatement of "the indirect method of inference" (§§44–46) into the machine lineage (§47 onward). He writes that "almost all the tediousness and liability to mistake may be removed from the process by the use of mechanical aids," and that in "practising myself in the use of the process, I was at once led to the use of the logical slate" — then, sections later, to the abacus and to "a successful working model of this contrivance, which may be considered a machine capable of reasoning."

The load-bearing point is what this does and does not connect. It does place the machine's origin, in Jevons's own words, in "this process of indirect inference" — the exact principle his 1864 Pure Logic illustrates with the Chrysippus three-road dog. So the dog and the machine share a concept: reasoning by elimination, the disjunctive-syllogism move made of slate and levers. It does not re-invoke Chrysippus, or any ancient, at the point of mechanization. The link between the dog and the machine runs through the shared concept across two of Jevons's own books five years apart — not through a single passage naming both. This is the textual spine under the vault's elimination-recurs through-line: an echo of principle, documented; not a cited lineage.