Above, an 1870 drawing by Washington Roebling showing the masonry of the Brooklyn tower of the Brooklyn Bridge. I guess it doesn’t quite qualify as art, although I’d certainly hang it on a wall. The lettering at the top and the 3D-effect frame around the image suggest that this was a presentation drawing of some kind, but that use seems to have drited. There are dimensions written in red ink – particularly at the lower left – that suggest that this was being used to track the work as it progressed. The plan section at the bottom is another annotation: while it is more carefully drawn than I could ever manage while hand drafting, the line work is clearly not part of the original. The fact that the plan crosses over the frame makes it clear this was an unplanned addition to the drawing; without the plan, the tower image is nicely centered in the frame.
The plan section is at the base of the tower, and while there is some hollow space in the flat areas below the arched openings, the buttresses are solid. My guess is that the shaded areas show granite blocks that were to be finished for show, as opposed to back-up blocks that could be rougher. The stone blocks in the “hollow” areas would never be seen. The two big rectangles are the actually hollow areas below the arches, with walls on all sides. This plan would be useful for calculating the volume of the two types of stone – finished and unfinished – which would be useful in calculating cost and setting a schedule.
