In Mongolia A map showing the location of Mongolia., 20th century, a unit of length, 3.50 yards (approximately 3.2 meters).


[Thai. ชั่ง] In Thailand, at least as early as the 17th – 20th century, a unit of mass, = 1.2 kilograms. link to page with chart showing relationships between Thai units of massForeigners often called the chang the “Siamese catty.”

In 1876, at the request of the Siamese government, the platinum-iridium prototype of the chang was evaluated by the Standards Dept. of the English Board of Trade. They found it equal to 2.674761 imperial pounds in a vacuum, and in air 2.675007 pounds.

This unit no longer appears in the Weights and Measures Act B.E. 2542 (1999).



Le mot de catì est Chinois, & s'appelle schang en Siamois; mais le catì Chinois vaut deux catìs Siamois.

The word catty is Chinese, and is called chang in Thai; but the Chinese catty is equal to 2 Siamese cattys.

[Simon] de La Loubère.
Du Royaume de Siam. Tome Second.
Amsterdam: Abraham Wolfgang, 1691.
Page 49.

La Loubère's description of the relationship between the Chinese and Siamese catties is wrong; actually 2 Chinese equalled 1 Siamese. This error was picked up and repeated by later Europeans. For example, echoing La Loubère John Bowring¹ says "Catty is Chinese, and in Siamese is called schang; but the Siamese catty is only equal to half of the Chinese" (page 259). He contradicts himself a page earlier, quoting “French authorities” as saying “Xang [French romanization of ชั่ง] = 1440 grammes...Catí = 720 grammes,” and a page later, relying on Crawfurd, he says “the commercial cattie being double the weight of the Chinese, which is 1 1/3 lb.”

Probably errors like that of Alexander (1840) who has a pecul of 100 catties, but = 2000 taels or 8000 ticals, are due to this confusion of catties.

1. Sir John Bowring, F.R.S., Her Majesty's Plenipotentiary in China.
The Kingdom and People of Siam. Vol. I.
London: John W. Parker and Son, 1857.


Please see Pallegoix. (1877)


Handelsgewicht. Das Haï (Hab, Hap) oder der Pikol von 50 Xâng oder Tschang zu 20 Tömlöng oder Tehl (Tails) zu 4 Bat oder Tikal. Da das Xâng = 2 chinesischen Kättis = 2²⁄₃ lb. engl. avdp. = 1,2095804 kg, so stimmt der Pikol mit den chinesischen überein und ist das Tömlöng oder siamesische Tehl = 1,6 chinesischen Tehl.

Sehr häufig dient auch das chinesische Kätti.

Commercial weights. The hap or picul of 50 chang, each of 20 tamlung or tael, each of 4 baht or tikal. Since the chang = 2 Chinese catties = 2²⁄₃ pounds avoirdupois = 1.2095804 kilograms, the tamlung or Siamese tael = 1.6 Chinese tael.

The Chinese catty is also frequently used.

Nelkenbrecher (1890), page 65.


In China, a unit of length, one of the Treaty measures, = 141 inches (about 3.581 meters) = 10 ch’ih. The modern romanization of this word is zhang, which see for the unit in other contexts.


Rules Respecting Trade and Dues

Note.-—These rules, as well as the tariff, formed a part of the British, American and French supplementary treaties signed at Shanghai, in November, 1858. The copy here given is that from the British treaty, and is in no material respect different from the others.

RULE 4.--Weights and Measures.

In the calculations of the tariff, the weight of a picul of one hundred catties is held to be equal to one hundred and thirty-three and one third pounds avoirdupois; and the length of a chang of ten Chinese feet to be equal to one hundred and forty-one English inches.

One Chinese chih is held to equal fourteen and one tenth inches English; and four yards English, less three inches, to equal one chang.

S. Wells Williams.
The Chinese Commercial Guide …. 5th ed.
Hongkong: A Shortrede & Co,
Page 70.

home | units index | search |  contact drawing of envelope |  contributors | 
help | privacy | terms of use