In glancing over the marginal list of scientific pursuits, I remark with pleasure the reference to _Optics_. I still recur with delight to the Undulatory Theory, once the branch of science on which I was best known to the world, and which by calculations, writings, and lectures, I supported against the Laplacian School. But the close of your remarks touches me much more--the association of the name of W. Struve and my own. I respected deeply the whole character of your Father, and I believe that he had confidence in me. From our first meeting in 1830 (on a Commission for improvement of the Nautical Almanac) I never ceased to regard him as superior to others. I may be permitted to add that the delivery of his authority to the hands of his son has not weakened the connection of myself with the Observatory of Poulkova. Acknowledging gratefully your kindness, and that of all the Astronomers of the Observatory of Poulkova, and requesting you to convey to them this expression, I am, my dear Sir, Yours most truly, G.B. AIRY. _To M. Otto von Struve, Director of the Observatory of Poulkova and the Astronomers of that Observatory._ * * * * * ROYAL OBSERVATORY, GREENWICH, _1881, August 3_. MY DEAR SIR, With very great pleasure I received the Address of the Astronomische Gesellschaft on occasion of my intended resignation of the Office of Astronomer Royal: dated July 27, and signed by yourself as President and Messrs Schoenfeld and Winnecke as Secretaries of the Astronomische Gesellschaft. I thank you much for the delicacy of your arrangement for the transmission of this document by the hands of our friend Dr Huggins. And I think you will be gratified to learn that it arrived at a moment when I was surrounded by my whole family assembled at my _jour-de-fête_, and that it added greatly to the happiness of the party. I may perhaps permit myself to accept your kind recognition of my devotion of time and thought to the interests of my Science and my Office. It is full reward to me that they are so recognized. As to the success or utility of these efforts, without presuming, myself, to form an opinion, I acknowledge that the connection made by the Astronomische Gesellschaft, between my name and the advance of modern astronomy, is most flattering, and will always be remembered by me with pride. It is true, as is suggested in your Address, that one motive for my resignation of Office was the desire to find myself more free for the prosecution of further astronomical investigations. Should my health remain unbroken, I hope to enter shortly upon this undertaking. Again acknowledging the kindness of yourself and the Vorstand of the Astronomische Gesellschaft, and offering my best wishes for the continued success of that honourable institution,