Six over Six -

Refer to a window panel near the center of the image. (Six panes over six panes, making twelve) The limitations of glass-making abilities at the time in the colonies meant panels had to be relatively small. Additionally, they were expensive, so glass panes were generally a luxury item that most farms had very few of. Most windows were reserved to be used on the home, were it was most essential, though if a barn had many windows, it meant the farmer was relatively well-off. If a barn had few windows, it either meant they were frugal, or may not have had enough money to invest into them. Early windows were twelve over twelve (three rows of four, each) but as techniques improved, larger panels could be made where six over six was standard (two rows of three, each) which became the standard in the 1800's -- allowing one to guess the relative era of a building by the type of windows it had.