Aconcagua. On 19 February 1949 Lieutenant William D. Hackett reached the summit of Aconcagua in company with an Argentine officer, Lieutenant Jorge Mottet. Hackett thus became the first to have ascended both McKinley and Aconcagua. The five-man climbing party, which was supported by six Argentine soldiers and a civilian, left Puente del Inca with 19 mules on the 15th; camped at Plaza de Mulas (4200 m.) on the 16th and 17th; and arrived at Refugio Plantemura (6400 m.) at 3.20 P.M. on the 18th. On the following day, which was clear and cold (—27° C.), Hackett and Mottet left camp at 10.00 A.M. and attained the summit (6960 m.), having climbed the last few feet together, at 6.00 P.M. They reached Plaza de Mulas about midnight.