Tarpit
By Jim Gould
East of Crooked Cartway. This depression was the site of manufacture of tar and charcoal. It is located in the conservation area east of Crooked Cartway/Farmersville Road, east of the crossing of a branch track from Crocker Road.
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In 1705 the British government subsidized colonial New England Production of naval stores like turpentine, pitch, tar and resin. The process was a sticky business, but very profitable. Turpentine was made by stripping the bark off pine trees (mostly white pines) even boxing the tree with a large gouge or box. The original forests of Cape Cod were mostly pitch pine (Pinus rigida) which produced the most sap. The product in greatest demand was tar, which was used to coat ships' rigging and to waterproof wood. This was produced in a pit or kiln, similar to the lime kiln or charcoal kiln. Aged pine logs were stacked in a circle around a wooden chimney and covered with a layer of leaves or straw, and an outer layer of earth. A fire set in the chimney was covered to produce a hot but slow-burning fire. A pipe inserted into the kiln drained out the tar. This could be boiled to produce pitch, used for caulking the underwater seams between the hull planks of wooden vellels. The charred wood that remained was sold to blacksmiths to achieve higher heat from it than they could from wood
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(Mikka Airaksinta "Tar Production in Colonial North America," Environment and History 2:1 (1996) pp 125,135 esp. 116 [Jstor].
Daniel Webb Fowler "Colonial Occupation: Collier (Charcoal Burner) blog 10 Aug. 2004.