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Photo image of a window glass pane section:Window Pane, Date: ca. 1711-1754, Site Name: Smith’s St. Leonard, Site Number:18CV91/171 - In the 18th-century, glass for windows was made in relatively small panes. That is because it was made by hand using a technique that gave it the name “crown” glass. A bubble, or crown, of heated glass was blown on a pipe, then opened at one end and spun so that centrifugal force caused the glass to expand into a large disk. These circular disks could only get so big, and the resulting glass was very thin, so in order to limit waste and minimize fragility, the disks were then cut into many small window panes. Glass made using this method tends to be more tinted than glass made today because of the chemical recipe used to make it. Crown glass can appear to have a slightly greenish or aqua color. When glass is deposited in the ground, it starts to slowly deteriorate in layers. As outer layers decay and separate from the surface, they change the way light passes through the glass, giving the appearance of a range of colors known as a patina. Some window glass will look iridescent, some will be a muddy green color, and some will even look like it has become crusty. This window pane from the Smith’s St. Leonard site has some very decayed “crusty” layers that look yellowish, while other areas have a pretty iridescent patina.