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Archeology for Interpreters > 5. How Do Archeologists Figure Out How Old Things Are?

Artifacts as time markers

Pipe stem dating

The clay pipe industry expanded rapidly as tobacco smoking gained popularity in both England and America. Historical archeologists excavating English colonial sites often find pieces of white clay smoking pipes on their sites. In the 1950s J. C. Harrington studied the thousands of pipe stems excavated at Jamestown and other colonial Virginia sites, noticing a definite relationship between the diameter of the pipe stem bore—or hole—and the age of the pipe of which it had been part. The earliest pipes, dating to about 1600, had stems with 9/64-inch diameter bores. By 1800 this diameter had decreased to 4/64 of an inch. This change in diameter may have occurred because pipe stems became longer through time, requiring a smaller bore. Louis Binford later devised a mathematical formula to refine Harrington's method (Deetz 1996:27). This dating technique only applies to pipe stems manufactured in England between approximately 1590 and 1800.

Case study

Tobacco Pipes at Jamestown
Learn how archeologists use smoking pipes to date historic sites.

Historical archeologists do not rely on pipe stem fragments as the only source for determining a site's history. They also consider historical documents and other material culture recovered from the site—such as ceramics, glass, metal artifacts, faunal and botanical samples, and features—to determine its occupation and use.

(image) Two clay pipe bowls

Parts of clay smoking pipes. (Heather Hembrey, University of Maryland)

Try it yourself

Pipe stem dating

You have recovered sixty-three pipe stem fragments from Verysignificantsite. You wish to analyze these pipe stems to determine when your site was most heavily occupied. According to J. C. Harrington's initial studies, the time periods and average bore diameters are as follows (Deetz 1996:28):

Diameter Dates

You have measured the pipe stem bores from your site and find the following distribution:

  Number of stems Bore diameter (in 64ths of an inch)  

Look at the number of stems you recovered and determine which bore diameter is represented by the most pipe stems. Match the most frequently occurring diameter with Harrington's bore diameter chart above.

Based on Harrington's table, when does this distribution suggest that Verysignificantsite was mosth eavily occupied?

1590-1620 1620-1650 1650-1680 1680-1720 1720-1750 1750-1800


How could you account for those pipe stems that fall outside this period?

A. The site was occupied less intensively before and after its heaviest occupation period
B. Pipe making technology varied enough to produce deviant bores
C. The clay pipe stem shrank or expanded from being in the ground so long.