# Where in Gauss's nachlass apears his sketch of a geometric proof for the biquadratic reciprocity law?

According to p.200-202 of the book "Reciprocity Laws: From Euler to Eisenstein" by Franz Lemmermeyer, there are two proofs for the biquadratic reciprocity law in Gauss's nachlass: one is a cyclotomic proof using Gauss sums which is very similar to Eisenstein's proof from 1844, and the other is an original contribution of Gauss - a sketch of a geometric proof of this theorem.

As for Gauss's cyclotomic proof - according to Bachmann (the editor of Gauss's number theoretical works) it cannot be dated, so it's unclear if it's original with Gauss or based on Eisenstein's proof. Since Lemmermeyer states that many of the proofs published after 1850 are just variations on Eisenstein's proof , i'm more interested in Gauss's geometric proof .