“Where columns are turned out of the solid, charge according to the trouble of procuring the stuff, sawing them off, hewing, and attendance on the boring, turning and fixing them up.”
Articles of the Carpenters Company of Philadelphia: And Their Rules for Measuring and Valuing House-Carpenters Work, Philadelphia, 1786
Interior columns were glued up. The Carpenters Company Rule Book states “Glewing (sic) up columns of plank to any of the orders” @ 2 shillings, 9 pence per foot.
Abraham Swan describes and illustrates that process in The British Architect .
Glue joints visible on the columns in the hall of the Pennsylvania State House after paint had been removed from the woodwork confirm this type of construction of interior columns.
But exterior columns, including the four massive columns in the two frontispieces at Mount Pleasant, needed to be solid as the joints of glued-up planks would not survive being subjected to weather. Trees needed to be felled, hewn close to the final shape, turned, brought to the site, and installed.
As seen in the State house columns, bases and capitals were most often made as separate elements from the shaft. The bases of the columns at Mount Pleasant were lost more than a hundred years ago, likely the result of rot. They are already missing in this stereoview of the east front made in the late nineteenth century.
The bases were poorly restored in the early twentieth century.
In addition to the restored bases lacking the correct Doric Order, the original plinths were most likely stone as seen in these surviving exterior columns in Philadelphia.
The modern bases were removed to examine the extent of restoration and the condition of the columns and wood samples were taken from all four columns for microscopic analysis to identify the wood species of the shafts.
This is a view looking up at the end grain of the bottom of the shaft of the column. The tightly spaced annual rings that are perfectly concentric denote a tree from an old growth forest that grew perfectly straight. Trees like this don’t exist anymore in the Delaware River Valley but were still available to carpenters and joiners one hundred years after British colonization.
At least at the bottom of the shaft there was no hollowing of the tree. We don’t know if there was wood removed higher up. Since a log shrinks evenly towards the center, the columns are still perfectly round but slightly smaller in diameter then when they were installed.
Counting the annual rings tells us these Red Pine trees had germinated by the middle of the sixteenth century, possibly in Pennsylvania, but just as likely in New Jersey. While an unimaginable use of material today, the ability to successfully spec and source “stuff” including the four perfect trees procured for the columns, was one of the motivations in hiring a leading member of the highly organized and influential Carpenters Company. Another was that that carpenter would have access to the best journeymen available in the city. On May 3, 1764, Thomas Nevell credited one of his journeymen, James Guy, 26 pounds for building the “Front frontish Piece Door”.
The original design of the column bases is easily determined. The Doric Order screen framing the stair just beyond the the frontispiece door, contains two pilasters nearly identical in size to the frontispiece columns.