1993年11月24日9时15分,我的老师周培源教授与世长辞了。我作为他的受业弟子,并且跟随他从事科学研究工作达四十有六年得益非浅的人,当然感到万分悲痛。回忆往事,历历在目。记得在1947年的秋天,当时全国战火纷飞,周先生刚从美国回来到清华大学任教。他一到校就给我们物理系二年级的学生开理论力学课。当时上课的教室是在科学馆三楼的306教室,离开他的 At 9:15 on November 24, 1993, my teacher Professor Zhou Peiyuan died. As a disciple of his profession, I certainly feel extremely saddened to follow the man who has benefited from scientific research for forty or six years. Memories of the past, vividly. I remember in the fall of 1947, when the war in the country was swirling, Mr. Zhou just returned from the United States to teach at Tsinghua University. As soon as he came to school, he gave us a theoretical mechanics class for second-year students in physics. Classroom was Classroom 306 in the Science Museum on the third floor, left him