ON October 22 and 29, Mr. J. W. Dunne, in whose book, “An Experiment with Time”, published a few years ago, evidence of apparent prevision of future events was presented, with a suggested explanation in terms of the character of the time concept” gave two lectures before the Royal College of Science Mathematical and Physical Society on “The Serial Universe”. Mr. Dunne described the nature of a ‘regress’, in which every term except the first is defined by its relation to the preceding and following terms and which therefore produces an infinite series. He showed that if, in the traditional manner of physics, we regard the’ scientific description of the world as being necessarily based on the exploration of an objective system with independently existing instruments of observation, we are compelled to employ a concept of time which is regressive, though it has not hitherto been so recognised. Such a con cept is adapted to our reasoning powers because we are self-conscious beings, and self-consciousness itself is essentially regressive. The difficulties of modern physics have arisen because attention has been con centrated on the first term only of the temporal regress, which lacks the vital double character of the succeeding terms. Mr. Dunne very acutely applied his ideas to the problems of relativity” attributing the appearance of ‘imaginary’ time in the Minkowski world to the rotation of the axis of second-term time though 90° into coincidence with that of first-term time” and to the quantum theory, in which the ‘uncertainty’ of Heisenberg's principle was found to be regressive and located in the instruments of observation instead of the world observed, which remained determinate. The substance of the lectures, considerably amplified, is to appear almost imme diately in book form.