In India, 19^{th} century, a nominal unit of mass used for the trade in pearls, which were priced per chow.
In Madras, the real weight was measured in mangelins (about 0.389 gram). To calculate the number of chows, square the weight in mangelins of a group of pearls. Take ¾ of the result, and divide by the number of pearls. Multiply the result by the price per chow (Grund suggests 96 shillings sterling per chow). In Madras the chow was divided into 16 parts.
In Bombay, the real weight was the tank. To calculate the number of chows, square the number of tanks, multiply by 330, and divide by the number of pearls. There the chow was divided as follows:
chow 

quarter 
4 

docra 
25 
100 

buddam 
16 
400 
1600 
Doursther, page 104.
Francis J. Grund.
The Merchant's Assistant or Mercantile Instructer [sic].
Boston: Hilliard, Gray & Company, 1834.
Pages 113 and 115.
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Last revised: 14 April 2008.