the promulgation of the Burney Treaty in June 1826, which ended three centuries of royal monopoly by granting the rights to the British to trade privately. However, some trade restrictions remained. Rice and ammunition were not permitted to be traded freely and British merchandise ships were still required to go through the Phra Khlang Sinkha for the measurement duties imposition. King Rama III, who ascended the throne in 1824, faced major financial problems. The Burney Treaty of 1826, which terminated royal trade monopoly, took drastic effect on the royal court revenue. King Rama III then realized that, instead of relying on the Royal Junks, the royal court should rather invest in tax farming. In his reign, thirty-eight new taxes were enacted to compensate the revenue loss. New tax farms required experienced collectors and the Chinese eagerly filled in these roles, leading to the creation of 'Chinese tax collector system'. When a new tax was announced, the Chinese merchants would compete for the rights to collect the tax on behalf of royal court. Those who promised highest amount of income would win this 'tax auction'. Deprived government revenues and decline in Chinese tributary trade in the 1840s pushed Siamese court towards more isolationist and conservative policies. Chinese tax farming system re-imposed restrictions and tariffs on most trades. British delegate Sir James Brooke, who argued that the Burney Treaty had not been honored by Siam, arrived in Bangkok in 1850 to find the Siamese court opposing any further concessions. In 1850, few years prior to the Bowring Treaty, Siam's total export value was around 5.6 million baht, with more than fifty percent came from natural products and fifteen percent from sugar export. Bowring Treaty and consequences: 1855–1873 Facing geopolitical pressures, Siamese government under liberal-minded King Mongkut and Chaophraya Si Suriyawong (Chuang Bunnag) gave in to British demands with the signing of Bowring Treaty in 1855. General import tariff was reduced and fixed at three percent ad valorem, which was lower than other Asian states including China's five percent and Japan's five percent, on all items except for opium and bullion. Phasi Pak Ruea or measurement duties, which was based on ship size, was abolished and incoming merchant ships were levied for duties only once along the course of trade venture, whether import or export. The rice export, which had been previously restricted due to concerns of national security, was liberalized. Revolutionary effect