Quote Originally Posted by Ole
All right, I have a few of these from before. But nothing like the ones that arrived today!

The first one is simply marked "A. T. Thompson & Co, Importers, Boston". According to the seller, it's 80mm across. Reading more critically, the glass is 8cm across, and 19 cm long... Anyway, it's a Petzval thingy, without aperture. .
Ole
According to my research, the A.T. Thompson Company was a Magic Lantern supplier here in Boston around the turn of the last century. All of the lens marked that way that I have seen have been large. Since I believe my own was once used in a college lecture hall at Harvard, I think the company may have specialized in
concert hall sized
machines. I'm happy hear that Jim believes them to be made by Darlot. Mine has only a mark on the flange saying "Made in France", nothing like a maker's mark. I've put mine on a Studio 7A - smallest thing that I could get to hold it. Have fun!