to 1885). The progress made in certain branches of science during this
long period can very fairly be traced by these Papers.

(4) His private correspondence was large, and like his other papers it
was carefully arranged. No business letters of any kind are included
under this head. In this correspondence letters are occasionally found
either dealing with matters of importance or in some way
characteristic, and these have been inserted in this biography. As
already stated the Autobiography left by Airy is confined almost
entirely to science and business, and touches very lightly on private
matters or correspondence.

(5) The letters to his wife are very numerous. They were written
during his occasional absences from home on business or for
relaxation. On these occasions he rarely let a day pass without
writing to his wife, and sometimes he wrote twice on the same
day. They are full of energy and interest and many extracts from them
are inserted in this history. A great deal of the personal history is
taken from them.

(6) All correspondence in any way connected with business during the
time that he was Astronomer Royal is to be found at the Royal
Observatory. It is all bound and arranged in the most perfect order,
and any letter throughout this time can be found with the greatest
ease. It is very bulky, and much of it is, in a historical sense,
very interesting. It was no doubt mainly from this correspondence that
the Autobiography, which so far as related to the Greenwich part of it
was almost entirely a business history, was compiled.

The history of the early part of his life was written in great detail