I found this picture on the cover of a 1940 instruction booklet for Bolex cameras.
Agenda for Friday September 30th,
We will be looking at your films in the morning and doing a sync sound shoot in the afternoon. I would also like to show a film about Marie Menken. I will be assigning your 2 page paper as well. Time permitting I would like to introduce 16mm production methods.
go to this link;