Oldest Cover in NYC
This unassuming little disk, protecting and illuminating a coal bin in Brooklyn Heights, might be the oldest surviving iron cover in the city. The Hyatt of the cover is Thaddeus Hyatt, and his patent was for the invention of the vault light design seen here. Cylinders of glass were placed in the holes of the metal plate to allow light into an underground vault, and they were protected from being damaged by the ring of metal studs surrounding each.
Having the date of the patent on the cover does not mean that that is when the cover was made, but, what makes this cover interesting is that not far away is another Hyatt cover (see below). That cover has three badges, one identifying the 'Manufactory' at 120 West Broadway, one stating "ORIGINAL PATENT 1845 NOV 13TH", and a third stating "T HYATT PATENTED 1855 MARCH 27". Hyatt was known for defending his patent rights, so the lack of that last date on this cover suggests (but doesn't prove) that this was made before 1855. That would make this one of the rare iron covers in New York that pre-dates the Civil War.
The honeycomb design becomes a natural fit once circular glass lenses become involved. The protective studs around the glass are the basis of the Hyatt patent, but the design of circles surrounded by studs persisted even when those circles were iron as well.
Although coal hole vault lights were not uncommon in both New York and Brooklyn, they essentially became superfluous as electric lighting spread throughout the two cities.
This cover is on Pierrepont St. in Brooklyn Heights, and is the only one of its type I have seen. Other vault lights are encountered in the older parts of 'Brownstone Brooklyn' and lower Manhattan. The other known Hyatt covers as well as an example of the larger vault lighting are right around the corner of Willow St.
Please note that this cover is on private property although it can be clearly seen from the sidewalk.