Blackett Memorial Lecture, 1978. Fundamental research in India in the area of the physical sciences

I consider it a great honour and privilege to have been invited to deliver the second Blackett Memorial Lecture organized under the joint sponsorship of the Royal Society and the Indian National Science Academy. I would like to express at the outset my gratitude to both Societies for providing me with this unique opportunity. It so happens that I have spent the last three decades of my life doing research in the field of cosmic radiation, a good fraction of which has been done with cloud chambers. Because of both these reasons, as you can easily imagine, I have been to a great extent personally influenced and inspired by P. M. S. (Lord) Blackett, whose pioneering and outstanding contributions in the field of cosmic radiation with counter controlled cloud chambers which brought him the Nobel Prize in 1948, are well known.