Figure M.1 – Zograscope Mirror

This is the diagonal mirror of my 18^th-century zograscope. I removed it and replaced it with a replica because the image quality is so bad. Note how the ripples in the mirror surface create waves though all the vertical lines in the reflected scene. While the silvering on mirrors can deteriorate over time, the glass will keep its original shape. So the ripples here are manufacturing defects.

 

Here is Joseph Harris's justification for why it made sense in the 18^th century to use such a mirror in an optical machine .