Looks like he was a Machinist for Hartford Empire Company at some point. Suppose he could have been involved with Phoenix Glass Co in 1883? I have an old check made out to Phoenix Glass Co that has a W J Miller signature on the back. That's why I was wondering if it was the same Miller.
In Baumann's book he writes the early machine could only round one marble at a time. He also writes a pair of workers could make 10,000 marbles in a ten hour day. I think that comes to about 1 marble every 7-8 seconds.
Baumann describes it as a single gather in his book as well, but the way it is written in both books it doesn't say if multiple marbles were from a single gather or not. So it may be possible.
Robert Block's book " Collecting Early Machine-made Marbles" (The M.F. Christensen & Son Company and Christensen Agate Company)
Here is a pic of a shear mark on a 13/16" Red Slag I have.
Robert Block and Baumann describe the early machine and shear process in his book. It was single gather and one marble at a time. So the Shear would only be on one pole of each marble. It makes sense the tails would be towards the shear mark because of how they turned and handled the gather.
Lets see if I can list them all.
Hot Wheels
Arrowheads
Old Medicine Bottles
Old Canning Jars
Old Books
Tom Clark Gnomes
Hummels
Old Cookie Jars
Old Salt & Pepper Shakers
Gemstones
Pottery
Knives
Hatchets
NC Seashells
Shark Teeth
Model Cars