Thanks everyone for the comments. I think Jay's notion it might be a chart recorder sounds plausible, and the images of vintage recorders Mr Google has found for me seem to be types that might have fitted the upper right rectangular area. I know it is not a good picture but it seems there might be two pen needles at the the bottom edge of the rectangle.
As has been noted, cctalk brings out some great anecdotes. I'm glad it's back up, I miss it when it's not. Steve
