Nhpharm, do you know if these were ever manufactured in the US? I've always assumed these to be British, we find them by the bucketload in turn of the 20th century sites in Canada, especially out west.
I am pretty much 100% certain that these were not made in the US. I dig them by the dozens in trash pits in Galveston, Texas and some of them still have the pigment attached from the labels, and they have all been British.