Easy electrical conduction in metals is usually attributed to the regularity of metallic crystals. Why then does the conductivity remain when a crystal melts? Pseudopotentials provide an answer.
Among shortcomings to be faced are projects that burden the National Science Foundation, rising costs of graduate science education, lack of coördination in attacks on social problems, and the poor flow of information from scientists to Congress.
Understanding has progressed from thermodynamic and phenomenological arguments to the pairing theory. Interest now is in problems of space and time variation of the pair potential and in theoretical prediction of relevant parameters.
The 1968 statistics revealed that physicists and astronomers as a group earned more than other physical scientists, had relatively more PhD's and worked principally in research and development.