Well, the truth is out. I actually do have a few pieces of glass in my collection. This particular CD 187 has a patent date and two segmented threads. I picked this up at a bottle show in the late seventies, probably driven to the show by my parents. It has lots of chips and other damage as it was dug. Don't recall seeing one of these at a show, but I am not usually looking for glass! Left to right: U-84 dry process, unmarked, Thomas, CD 187, U-81, unmarked, Pittsburg, wet process.