I am,
My dear Mr Christie and Gentlemen,
Yours faithfully,
G.B.  AIRY.

* * * * *

Throughout his tenure of office Airy had cultivated and maintained the most friendly relations with foreign astronomers, to the great advantage of the Observatory.  Probably all of them, at one time or another, had visited Greenwich, and to most of them he was well known.  On his retirement from office he received an illuminated Address from his old friend Otto Struve and the staff of the Pulkowa Observatory, an illuminated Address from the Vorstand of the Astronomische Gesellschaft at Berlin signed by Dr Auwers and the Secretaries, a complimentary letter from the Academy of Sciences at Amsterdam, and friendly letters of sympathy from Dr Gould, Prof.  Newcombe, Dr Listing, and from many other scientific friends and societies.  His replies to the Russian and German Addresses were as follows: 

ROYAL OBSERVATORY, GREENWICH,
1881, August 5.

MY DEAR SIR,

I received, with feelings which I will not attempt to describe, the Address of yourself and the Astronomers of Pulkowa generally, on the occasion of my retirement from the office of Astronomer Royal.  I can scarcely credit myself with possessing all the varied claims to your scientific regard which you detail.  I must be permitted to attribute many of them to the long and warm friendship which has subsisted so long between the Directors of the Pulkowa Observatory and myself, and which has influenced the feelings of the whole body of Astronomers attached to that Institution.  On one point, however, I willingly accept your favourable expressions—­I have not been sparing of my personal labour—­and to this I must attribute partial success on some of the subjects to which you allude.

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.