About a dozen students occupying the clock tower at Cooper Union, protesting the decision by the president of one of the last remaining institutions to offer students a tuition-free education to take it off that short list. The students, who began their protest Monday, vowed Tuesday to remain until their list of demands, including the president’s resignation and a hiring freeze, are met. The occupation is the latest action by students unhappy with the steps taken by President Jamshed Bharucha, who said in April  that the institution would start charging for some new graduate programs, and might start charging tuition for all students after 2013. Police have been in and out of the clock tower, and Bharucha said in a statement Tuesday that his first priority is the safety of the students, whose full tuition is covered through scholarships. Faculty members held a press conference at the site Tuesday afternoon, reaffirming their support for a tuition-free college.