I've got some diffuser lenses from some recessed fluorescent fixtures in a building built in 1949.  These fixtures were set in a hard plaster ceiling.  I'd like to know a probable manufacturer.  Anyone have an idea who might have produced these?  Photos attached.

These might be made by Holophane. I believe they produced a lot of the glass for early fluorescent fixtures.

Thanks! 

May I ask what size tube they use?

There were four diffusers per fixture so I assume normal 48" tubes.  I think there were two or three tubes in each fixture.  Don't remember exactly.