I was a student of Prof. Charles H. Townes in the summer of 1951 when he was working out the theory of the microwave maser. None of us in his class on Vector and Tensor Analysis knew this was going on -- learning of it only a year later. But we knew he was acting peculiarly.

He would stop writing on the blackboard, "go off in thought" for several minutes, before recovering and going on with his work. Sometimes he would put his head against the blackboard, close his eyes, and seeming to nap, then recover. Several times, Townes cut the period short -- with a remark about "such a nice day" or whatever -- and dismiss the class. As a result, we learned little math from him and had to teach ourselves from the textbook and what we could find in the Library.

The maser was used to develop a clock more accurate than any known prior to this. Years later, the process was activated in terms of visible light, resulting in the laser.