The interest and income of the entire residue of the proceeds of the said lands be, and are hereby appropriated, and the commissioners under the said act, are also hereby directed to pay the same, as it shall accrue, to the agricultural college of Pennsylvania, for the endowment, support and maintenance thereof, on condition that the trustees establish, conduct and maintain, in connection with the college, three experimental farms; one near the college, under the immediate supervision of the professor of agriculture in the institution, another east, and the other west, upon lands of diversified quality, under the immediate supervision, respectively, of an assistant professor of agriculture.