[adam_777]

Its possible that the observatory was never used of course, however the Matsui Drawing I am referring to was done as a way to show that 40 Wall had the highest occupied floor over the completed Chrysler with its spire and should be considered the tallest, so very shortly before the building opened it was still being referred to as an observatory. But maybe it never actually functioned as one, either way the area the drawing refers to is the piston shaped area that sits on the top of the pyramid, I'm skeptical that such a space could have been converted to anything else as it is very small almost lookout or crows nest area similar I am guessing to the top of the Woolworth building.