The story of the analogy between knots and primes, which now has a literature, started with an unpublished note by Barry Mazur.

I'm not absolutely sure this is the one I mean, but in his paper, Analogies between group actions on 3-manifolds and number fields, Adam Sikora cites

B. Mazur, Remarks on the Alexander polynomial, unpublished notes.

He also cites the published paper

B. Mazur, Notes on étale topology of number fields, Ann. Sci. Ecole Norm. Sup. (4)6 (1973), 521-552.

I suppose an expert would recognize as relevance of this paper, but I don't see that even the word "knot" ever occurs there.

[My Question] Does anyone have a copy of Mazur's note that they would share, please? If not, has anyone at least actually seen it.

By the way, already years ago, I asked Mazur himself. I watched him kindly search his office, but he came up dry.

I realize that whatever insights the original note contains have doubtless been surpassed after c. 40 years by published results, but historical curiosity drives my desire to see the document that started the industry.