Referee's report by Edward Crisp Bullard, on a paper 'The disturbance due to a line source in a semi-infinite elastic medium' by E R Lapwood Sectional Committee: Mathematics Recommended for publication in the Philosophical Transactions of the Royal Society. The paper is 'a solid and important contribution to a very difficult subject'. The paper is long but cannot be cut down without loss of clarity. Has not checked the mathematics, but as Harold Jeffreys has taken an interest in the work, there can be no serious flaws. [Published in the Philosophical Transactions of the Royal Society] No received date. [1948]