Time travel has shifted from pure fantasy to a serious, if highly constrained, topic in modern physics. The equations that ...

IN our issue of December 9, 1922, p. 792, we directed attention to the first of a series of reports on the teaching of physics in the United States by a committee of the American Physical Society ...

IT is some twenty-five years since the first edition of this book was reviewed in these columns. In several subsequent editions, including the present one, it has undergone some revision, chiefly ...