Before the American colonies declared their independence in 1776,
England (later,
Great Britain)
passed many laws limiting trade and manufacturing in its colonies.
  The
purpose was to protect English businesses and Crown wealth under an economic
policy known as mercantilism. This policy
protected English manufactures from competition by manufacturers in its colonies, which were
allowed to produce only raw materials or partly finished goods for manufacture in Great Britain.
The policy also created a favorable trade balance so that the value of goods exported
from England was higher than those imported, so that the English government accumulated
gold; that is, it became wealthy.
The laws passed under this policy collectively are known as the Navigation Acts and
can be summarized as follows:
- Goods imported and exported into the American colonies must use English
ships;
- Ship's crews must be at least 3/4 English or colonial;
- The colonies could export certain goods, the so-called "enumerated goods"
only to England;
- Most colonial goods had to be unloaded in English ports.
On October 30, 1650, the English Parliament enacted laws that required foreign ships to
obtain licenses to trade with the American colonies.   The purpose of these actions
was to reduce the very competitive Dutch supremacy in ocean trade.   Later, on
October 9, 1651, Parliament ruled that imports from the American colonies must be in English
ships and from points of production.   This law, known as the first (one of a series)
Navigation Act, caused problems for American
exporters and English importers because
England did not have enough ships for the trade.   Irate colonists insisted
on trade freedom and continued to use Dutch ships.
In October, 1660, an expanded Navigation
Act was enacted.   This act required trade
with the American colonies to be in English-built and -owned ships with crews composed
of at least 3/4 Englishmen.   Also, enumerated colonial goods, such as indigo, sugar,
cotton, wool, ginger, and tobacco could be shipped only to England.
On July 27, 1663, the second Navigation
Act was enacted to provide that all imports to the American
colonies with the exception of salt, wine, servants, horses, etc., from other countries
must be transported from England in English ships.
In 1699, to protect its wool industry, the English Parliament passed
the Wool Act that limited wool production in Ireland
and forbade wool export from American colonies.
In 1705, Parliament passed a trade act that expanded the number of colonial
products that were to be exported only to English ports: rice, molasses and
naval stores (pitch, tar, rosin, turpentine and hemp).   Parliament also added
bounties (subsidies) for the export of naval stores from the colonies.
In 1729, the British Parliament renewed its
bounties (subsidies) on naval stores: pitch,
tar, rosin, turpentine, hemp, masts, yards and bowsprits exported from the colonies.
These bounties continued to 1774, but the hemp bounty lapsed in 1741, and was
reinstated in 1764.
On May 17, 1733, Parliament passed the Molasses
Act, which
posted large duties on all molasses, rum and sugar imported to the American
colonies from non-British Caribbean Islands.   This Act attempted to
force American traders to buy higher cost sugar and molasses from British
Caribbean planters rather than lower cost sugar and molasses provided by French and
Dutch Caribbean planters.
On May 13, 1748, Parliament enacted a bounty (subsidy) of six pence per pound
on indigo imported from the American colonies.
In 1750, Parliament enacted the Iron Act,
which forbade the construction of rolling
and sheeting mills, steel furnaces and tilt-hammer forges in the American colonies.
  This legislation also allows duty-free export of colonial pig and bar iron into
Great Britain under specified conditions.
The purpose of this legislation was to
prevent the colonies from competing with British iron manufacturers and encourage
the export of raw iron products from the colonies.
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In 1763, Parliament reduced the bounties (subsidies) on indigo, a staple crop of
the southern colonies. Indigo is a dye used in the British
woolen textile industry.
On April 5, 1764, Parliament enacted the American Revenue Act, known in the
colonies as the Sugar Act.   While earlier acts
were designed to protect
British manufacturers against American competition, the purpose of this act was
to raise revenue for the British government to defray its large debt incurred by
the French & Indian War that ended in 1763.   The Sugar Act imposed new and
higher duties on many American exports and foreign refined sugar.   It also
doubled the duties on foreign goods re-shipped to the colonies from Great Britain.
  This act and other enacted at the same time are collectively known as the
Grenville Acts, after British Chancellor of the
Exchequer, Lord Grenville.  
One of these acts also reorganized the customs laws so that trade laws could be
enforced more effectively.   For example, the vice admiralty court was
located at Halifax, Nova Scotia with jurisdiction over all the American colonies.
The Navigation Acts were repealed in 1849.