Need help on this strange military slide projector

[Gunny Hooch]

This a military slide projector which is marked US Army Air Forces by the Society for Visual Education. Serial # is 109. Ive been trying to research this but not having much luck.
I know similar ones might have been used in Pre Flight Briefings or Trainings and even in the
Medical Corps field.

But what is unusual to this particular projector is the case its in which is original to the projector, it has a Altimeter Gauge on it and a place to add oil ?
When the projector is plugged in, the Altimeter gauge lights up and seems to be working.

Can or has anyone seen one of these before ? and whom might be able to explain why
a altimeter gauge is present on this projector ?

I am wondering if at some point in time perhaps it was used in a Aircraft for some reason or another ????

Any help on this would surely be appreciated



Thanks for viewing....