The first corner windows appeared in New York apartments around 1928. I know of a building constructed that year where the columns are numbered consecutively on the structural drawings, but the four numbers that should logically represent the corner columns are missing from the list, suggesting that the building was originally designed with corner columns and altered during design to omit them. There are a good number of steel-frame apartment houses from the 30s, and some from 1929, that do not have corner columns, allowing for corner windows.
This is purely a stylistic phenomenon. There is no great advantage to corner windows, even in terms of view. The presence of corner windows in those steel-frame buildings indicates a certain maturity of structural analysis and design, and was typically used in variations on Art Deco styling.
The photo above, of a 1949 apartment house in Queens, is something else entirely. As is true of most post-war mid-rise apartments in Brooklyn and Queens, it is very plain architecturally and has masonry bearing walls structurally. In a steel frame building, the spandrel beams cantilever past the columns closest to the corner to support the floors and exterior-wall masonry at the corners. In a bearing-wall building that’s a much more difficult detail, because there are no columns to tie those cantilever beams to. Hence the title of this post: the design cheats. The large mullion at the corner, where the windows on one wall meet the windows on the other, hides a small column. In the buildings where I’ve actually seen that hidden column, it was a steel angle. That allows non-cantilever beams to support the floors and walls at the corner, and the corner-window appearance, originally an artifact of steel-skeleton framing, can be used in bearing-wall buildings.
And, this should probably be in the first paragraph, but if you earnestly believe in structural honesty in architecture, this detail is not for you.
