Copy letter from Arthur Schuster, Secretary of the Royal Society to Professor William Arthur Bone FRS 'I am sending enclosed a few suggested amendments of the theoretical part of your paper; also copy of notes referring to the apparatus used by you, which appears to be substantially the same as that designed by Professor Petavel. A substantial portion of the figures illustrating your apparatus has indeed already appeared in the Philosophical Transactions. I would suggest that some acknowledgment should be made in the paper, embodying the explanations in the enclosed notes. It would help the Committee materially in their decision if I could hear at your early convenience how you propose to deal with these suggestions. P,S. If you have not kept a copy of the paper I can send you the original for reference.' 29 April 1915