And then another remarkable thing happened, which again changed my life. Bragg decided to leave Manchester and to accept an appointment as Director of the National Physical Laboratory. Now, to save any confusion I will say straight away that Bragg only occupied the post of Director of the NPL for about a year. He then succeeded Rutherford as the Cavendish Professor, so he will be remembered as the Cavendish Professor and it may be forgotten that he did spend about a year as a Director of the NPL. Well, there was great interest and rumours as to who would succeed Bragg as the Langworthy Professor of Physics and director of the physics laboratory. An amazing succession, Schuster, Rutherford, Bragg. Who would succeed him? The various rumours... Chadwick, for example, was mentioned who discovered the neutron but Hartree then informed me that Blackett had been appointed to succeed Bragg. Now this was an amazing change. Hartree had said that he had written to Blackett and thought that this boy Lovell would be interested in carrying on research on cosmic rays in Manchester. And so Blackett asked me to go to London and take over a marvellous device, an automatic cloud chamber, which had been used by one of his Chinese students, Yu Shien Shan, who decided to return to China in order to help in the war against Japan. It was by the end of... so I collected this equipment and got it transported to Manchester, and by the time Blackett arrived at the end of 1936 or 1937, I had this expansion chamber working in the Schuster Building.

Now, then became a very exciting couple of years. I ought to say that my association with Blackett became lifelong, and he will... I will say a bit about him now, because his name will appear frequently in the account of my life. He had been a Naval Lieutenant in the war. Those whose career had been interrupted, The Royal Navy allowed them to return to complete their education and Blackett went back to Cambridge and spent one night there and immediately decided to resign his commission and work with Rutherford, and it was there that he did this famous work in the Rutherford Laboratories on the display and disintegration of an atom in the cloud chamber and then the discovery of the positive electron with Occhialini, and he then had some disagreement with Rutherford and got the job as professor in the Birkbeck College, London, which was then really a college for night students. And Blackett had built an enormous electron magnet in which he could place his cloud chamber, and thereby from the curvature of the tracks measure the energy of the particles. And it was that great enterprise in which I became deeply involved in Manchester in 1938 and 1939.