lately employed some time in drawing up a series of skeleton annals of the Observatory (which unavoidably partakes in some measure of the form of biography), and have carried it through the critical period, 1836-1851.  If I should command sufficient leisure to bring it down to 1861, I think that I might then very well stop.” (The skeleton annals here referred to are undoubtedly the manuscript notes which form the basis of the present biography.  Ed.)—­“On Feb. 23rd in this year I first (privately) formed the notion of preparing a numerical Lunar Theory by substituting Delaunay’s numbers in the proper Equations and seeing what would come of it.”

Of private history:  There was the usual visit to Playford—­in this year later than usual—­from Feb. 4th to Mar. 4th.  The letters written during this visit are, as usual, full of freshness and delight at finding himself in his favourite country village.—­On June 5th he went to Barrow House, near Keswick, to be present at the marriage of his second son Hubert to Miss S. C. Langton, daughter of Z. Langton Esq., of Barrow House.—­After the wedding he made a trip through the Trossachs district of Scotland with his daughter Annot, and returned to Greenwich on June 17th.

On the 26th June 1872 Airy was appointed a Knight Commander of the Most Honourable Order of the Bath:  he was knighted by the Queen at Osborne on the 30th of July.  In the course of his official career he had three times been offered Knighthood, and had each time declined it:  but it seemed now as if his scruples on the subject were removed, and it is probable that he felt gratified by the public recognition of his services.  Of course the occasion produced many letters of congratulation from his friends:  to one of these he replied as follows:  “The real charm of these public compliments seems to be, that they excite the sympathies and elicit the kind expressions of private friends or of official superiors as well as subordinates.  In every way I have derived pleasure from these.”  From the Assistants of the Royal Observatory he received a hearty letter of congratulation containing the following paragraph.  “Our position has naturally given us peculiar opportunities for perceiving the high and broad purposes which have characterized your many and great undertakings, and of witnessing the untiring zeal and self-denial with which they have been pursued.”

* * * * *

On the 18th of March 1872 Airy was nominated a Foreign Associate of the Institut de France, to fill the place vacant by the death of Sir John Herschel.  The following letter of acknowledgment shews how much he was gratified by this high scientific honour: 

ROYAL OBSERVATORY, GREENWICH,
1872, March 23.

A Messieurs
  Messieurs ELIE DE BEAUMONT,
  et J.B.  DUMAS,
  Secretaires perpetuels de l’Academie
  des Sciences, Institut de France.

GENTLEMEN,