The purpose of the 1836 strike in Lowell, Massachusetts was to protest reduced pay for mill workers. The mills had announced that they would be cutting wages, and the workers decided to strike en masse in response. The passage describes how the girls went on strike, shut down the mills, and listened to speeches from early labor reformers. One of the girls even gave a speech herself, declaring that it was their duty to resist all attempts at cutting down wages. Therefore, the answer is "to protest reduced pay for mill workers."