[5] It was also the third of four successive Supreme Court cases related specifically to the Oliver Evans flour mill patent.

After keeping his invention a secret while he reduced it to practice, he initially obtained protection for it through individual state statutes, for example in Maryland[7] and New Hampshire,[8] because the patent system did not yet exist.

[10] He was unsuccessful until 1808, when the Tenth Congress passed a law authorizing the Secretary of State to grant him a new patent on the same terms as the original one.

By the same token, it also created confusion as to the kind of prior art that would suffice to invalidate the patent on the basis of anticipation.

[14] The court also declined to admit the plaintiff's proffered evidence that the defendant had initially offered to pay a license fee to Evans.

Evans died two years before the Supreme Court ruled on this second appeal; his factory had been destroyed by fire in 1819.

[13] This doctrine ultimately gave rise to the requirement for separate, distinct claims, as adopted in the Patent Act of 1836.

[25] However, in modern jurisprudence the written description requirement did not re-emerge as a distinct issue until the passage of the Patent Act of 1952.