Modern scans may show traces of the original dimensions of the ‘tefach’

The tefach, an ancient unit of measurement, was used by ancient Israelites.

Ortal Harush with one of the Iron-Age jars found in Khirbet Qeiyafa (photo credit: HEBREW UNIVERSITY)
Ortal Harush with one of the Iron-Age jars found in Khirbet Qeiyafa
(photo credit: HEBREW UNIVERSITY)
Modern-day sukkah builders may find it interesting that recently created 3D scans of ancient pottery could reveal the original dimensions of the tefah, a unit of biblical measurement based on the dimensions of a male hand.
The tefah was used primarily by ancient Israelites. It appears frequently in the Bible and is the basis for many Jewish laws. It is an especially important measurement at this time of year, as it is used by observant Jews to calculate the precise dimensions according to Jewish law for building a sukkah, the outdoor structure where the holiday of Sukkot, which begins on Friday, is celebrated.
In a paper published recently, three Israeli archaeologists report that they found a surprising common denominator in a variety of storage jars from a period of over 350 years, from the Kingdom Judah and the Israelite Kingdom: the inner-rim diameter of the jars’ necks are consistent with measurements of the palm of a male hand and may reflect the original metrics for the biblical measurement of the tefah.
The three archaeologists – the Hebrew University of Jerusalem’s Ortal Harush, Antiquities Authority’s Avshalom Karasik and Weizmann Institute of Science’s Uzy Smilansky – published their findings in the Bulletin of the American Schools of Oriental Research, which is published by the University of Chicago Press Journals.
In the article, the researchers describe how they did 3D scans of 307 Iron Age jars found in Khirbet Qeiyafa from the Judean Kingdom in the early 10th century BCE; “hippo” jars from northern Israel from the Israelite Kingdom, ninth century BCE – nicknamed for their large size and loop handles which were thought to resemble hippopotamuses; and royal Judean Kingdom storage jars from the 8th-7th century BCE.
“It was natural for the ancient potters to adopt the handbreadth – tefah – standard. It was a unit of length that was widely used in ancient times, and is mentioned both in Assyrian and Egyptian sources and in the Old Testament, for instance: Numbers 25:25, Numbers 37:12,” the researchers wrote.
The team observed large variations among the jars – even those from the same time period and geographic region. Only one measurement remained constant: the average inner-rim diameter, which always measured, with a standard deviation, between 8.85 and 8.97 centimeters.
The distribution of this diameter is statistically identical to the average male hand’s breadth. To ascertain the standard measure of a modern man’s palm, the team examined measurements taken by the US Army when ordering gloves for its soldiers, which was consistent with the measurements taken from the ancient jars. Though human heights and weights have changed over time due to many factors, including improved diet and health, previous research has shown that palm dimensions have not changed much over the last 3,000 years.
The researchers have several theories as to why the inner rim has remained the same while the overall shape of the jars varies so much. They theorize that the inner rim stayed consistent because it was a natural choice for ancient potters to use their palms as the standard diameter for jar openings. And since storage jars were used for years, it was important to be able to fit hands into jars to clean them.
The researchers also theorized that the biblical purity laws also played a part in the uniform dimensions of the inner-rim diameter. The Book of Numbers deals with the question of whether jars left in the vicinity of a corpse were ritually pure or impure. Numbers 19:14-15 states, “This is the law, if a man dies in a tent, anyone entering the tent and anything in the tent shall be unclean for seven days. Any open vessel that has no seal fastened around it becomes unclean.”
According to these lines, the contents of a jar left near a corpse would become impure and unusable unless there was a special seal on its top. Over the centuries, Jewish authorities quantified these rules of impurity, stating that the minimal opening size through which impurity may enter is the square of a hand’s breadth by hand’s breadth, or tefah by tefah.
Over time, various rabbis attempted to provide conversions of the traditional biblical measurements to modern measurements. The conversions for the tefah vary, with competing theories from Avraham Chaim Naeh and the Chazon Ish, both 20th-century Orthodox rabbis who lived in pre-state Israel. According to Naeh, one tefah is equal to 8 cm., whereas according to the Chazon Ish one tefah is 9.6 cm. The uniform opening of the ancient storage jars, which is between 8.85-8.97 cm, falls squarely in between these two opinions and may shed light on the dimensions of the biblical tefah, dimensions that determine so much of religious law.