The next morning they were unable to start a fire using friction due to the thin air at that altitude, and sent for matches. By this time, the naval officers and Hawaiians could not agree on terms to continue hiring porters, so sailors and marines were ordered from the ships. Dr. Judd traveled between the summit and the Recruiting Station to tend the many who suffered from altitude sickness or had worn out their shoes on the rough rock. Christmas Day was spent building rock walls around the camp to give some protection from the high winds and blowing snow. It took another week to bring all the equipment to the summit, including a pendulum designed for measuring slight variations in gravity.