Referee's report by William George Penney, Baron Penney of East Hendred, on a paper 'The diffraction of blast. I' by Michael James Lighthill Sectional Committee: Physics Recommended for publication in the 'Proceedings of the Royal Society of London'. There are as yet no experimental results on against which the theory can be tested. Suggests a change to the title, as the term 'blast' is misleading. [Published in the 'Proceedings of the Royal Society of London'] No received date. [1948]