Copy letter from Sir Joseph John Thomson, President of the Royal Society, to Sir James Dewar 'Owing to the very serious condition of my brother I cannot now do more than acknowledge the receipt of your letter of July 6th and must leave the reply to it for a later date.' [Note: this letter appears at the bottom of the same page as the previous letter from Dewar to Thomson, CD/32/8.] 9 July 1917