In 1767, the Parliament passed the Townshend Acts which placed duties on a number of staple goods, including paper, glass, and tea, and established a Board of Customs in Boston to more rigorously execute trade regulations. The new taxes were enacted on the belief that Americans only objected to internal taxes and not to external taxes such as custom duties. However, in his widely read pamphlet, "Letters from a Farmer in Pennsylvania", John Dickinson argued against the constitutionality of the acts because their purpose was to raise revenue and not to regulate trade. Colonists responded to the taxes by organizing new boycotts of British goods. These boycotts were less effective, however, as the goods taxed by the Townshend Acts were widely used.