Yep. There was an obvious answer out there, and I was in fact missing it.
I suspected the Sun was an Eagle product. I was sure it was an Eagle product. But at the time, all I could say was I was pretty sure. Or almost pretty sure.
Turns out, all I had to do was quit looking, and quite by accident the answer poked out of the bushes and mooned me. While I was looking for something else, I stumbled across an expired trademark:
And speaking of the copying lead that was the subject of Walpuski's patent, a couple months ago I found this bunch of Eagle copying lead in an online auction:
These all have the Walpuski patent date of June 26, 1877 on them, but there's also another patent date of May 29, 1879:
There's only one problem. The United States Patent Office didn't issue any patents on May 29, 1879. This is likely a misprint of May 20, 1879, the patent date for one of Joseph Hoffman's designs for the Eagle Stop Gauge pencil (see the article posted on February 13).
These little boxes are packed with a lot of information, especially concerning the numbering and grades of copying lead offered:
"1/4 dozen," huh? That must be way better than "three."
On the reverse of these tiny boxes are some pretty detailed descriptions, which almost look to be handwritten: