| Description | He gives thanks for the proof [of 'The refractive indices of water and of sea-water' by J.W. Gifford], which he has corrected. He has written a new footnote, which is exacttly what Larmor said in his letter, with the addition of Dufet. The reference to Dufet is on a separate sheet, so that Larmor can remove it if he does not like it. He thanks Larmor for the trouble he has taken. Larmor may be interested to know that with the indices, he has calculated the use of a submarine lens. This has been made and tried at Torquay, although the sea water was only clear for ten feet. |