I recently bought a large collection of insulators and I spent the day sorting them. It is said to save the best for last and that is exactly what happened. This Hemi No 9 patent date was the very last insulator in the last box. Once I pulled it out, you can imagine my joy when I noticed huge amounts of black carbony swirls deposited inside the skirt all the way up to the dome. All the black you see backlighted in this guy is carbon, not dirt. Not only that, but all the places where the carbon has been folded in has that weird, satiny sheen to it where the glass surface mixed with the carbon. Just love those happy endings!