The Old First Church in the Old Center of Bennington, Vermont, was built in 1805. The congregation, needing a new building, hired the master builder/architect Lavius Fillmore of Connecticut. He had already constructed several churches in Connecticut. He built 2 more in Vermont.
The church as been in use since it was built. It has an active congregation.
I am one of the docents (tour guides) for the church. We open the church during the week for visitors. We answer tourists' questions about church customs in 1805, theology, local and New England history, and sometimes even its architecture. We encourage people to walk around the church and the cemetery.
One part of the building I have been studying is the window sash pattern. The upper windows are arched: double hung windows with half circle tops. There are also Palladian windows. Where did the shapes of the curves in the arches come from?
Fillmore had a design in mind. How did he show the carpenter/joiner making the sash how those pointy pieces of glass and the muntins, the wood that holds them in place, were to be fashioned?
The use of circle geometry to determine the regulating architectural lines of buildings was common knowledge in 1800. So I began my exploration with circles.
Here is what I have found:
The top diagram shows the 5 panes of the Palladian windows with their arch. The lower diagram is the simpler 4 pane wide window.
The circle which determines the shape of the half circle arch, also determines the shape of the 'pointy' panes within the arch. The circles come and go in both directions. It is the center half circle which contains the expansion, 'centering' it.
Once I saw that, it was so obvious! I felt as if I had not played with my compass enough when I was little!
I thought I'd try the pattern in the arch over the main front door....
This pattern is more complex. The circle is surrounded by its 6 circles, starting with points on the left and right sides of the circle. The crossing points of the outer circles are centers for the curved segments in the center half circle. The pattern is then repeated starting at the top and the bottom points of the circle, or a 30* shift from the first pattern. The 2 patterns are combined to make the scalloped edge.
Well, what about that 3 leafed 'flower' - 'crown' - in the center?
I don't know. I do think the answer will be obvious when I find it.