Rotblat writes regarding E.C. McIntosh's ideas. He apologizes for not having written BR sooner about them.

He points out two problems with McIntosh's ideas, the first being "... in relation to pressure; even at a considerable depth in the ocean the gravitational pressure would still be small compared with the pressure developed at the instant of a hydrogen bomb explosion. Secondly, the process of fusion involving hydrogen is extremely slow since it depends on a beta-emitting reaction.... It is completely out of the question that all the water in the oceans could be made to undergo a thermonuclear reaction in the conditions prevailing at any depth in the ocean."

Note at the top in Edith's hand: "Copy sent to E.C. McIntosh 21/7/62".