4. Coal Hole Covers
Like in London, the original street covers were for coal–and were often originally rectangular in shape. New York City still has many covers that lead to former coal chutes, like the one above in a hexagonal shape. This particular one, found in Brooklyn Heights, is a patented “illuminated cover” invented by J.B. Cornell, an ironworks company founded by brothers on Centre Street.
The patent document from 1856 describes glass panes placed between melted brimstone. John B. Cornell writes that the design will be kept clean from the “friction of passing feet,” and that a light rain shower would remove “any considerable quantity of dirt” from the glass panes. For this and various reasons, Cornell believed “in point of illuminating power, and safety against the entrance of moisture, I believe that my improved illuminating cover for openings in pavements &c. has no equal.”