ton and Grasmere to Portinscale, and
spent the rest of his time in expeditions amongst the hills and visits
to friends.--On July 28th he went to Woodbridge in Suffolk and
distributed the prizes to the boys of the Grammar School there.--From
Oct. 9th to Nov. 12th he was again at Playford.--Throughout the year
he was busily engaged on the Numerical Lunar Theory, and found but
little time for miscellaneous reading.

Of printed papers by Airy in this year the most important was one on
the "Results deduced from the Measures of Terrestrial Magnetic Force
in the Horizontal Plane," &c. This was a long Paper, communicated to
the Royal Society, and published in the Phil. Trans., and was the last
Scientific Paper of any importance (except the Volume of the Numerical
Lunar Theory) in the long list of "Papers by G.B. Airy." The
preparation of this Paper took much time.--Of miscellaneous matters:
In May a Committee of the Royal Society had been appointed to advise
the India Office as to the publication of Col. J. Herschel's pendulum
observations in India; and Airy was asked to assist the Committee with
his advice. He gave very careful and anxious consideration to the
subject, and it occupied much time.--In the early part of the year he
was asked by Sir William Thomson to assist him with an affidavit in a
lawsuit concerning an alleged infringement of one of his Patents for
the improvement of the Compass. Airy declined to make an affidavit or
to take sides in the dispute, but he wrote a letter from which the
following is extracted: "I cannot have the least difficulty in
expressing my opinion that you have made a great advance in the
application of my method of correcting the compass in iron ships, by
your introduction of the use of short needles for the compass-cards.
In my original investigations, when the whole subject was in darkness,
I could only use existing means for experiment, namely the long-needle
compasses then existing. But when I applied mechanical theory to
explanation of the results, I felt grievously the deficiency of a
theory and the construction which it suggested (necessarily founded on
assumption that the proportion of the needle-length to the other
elements of measure is small) when the length of the needles was
really so great. I should possibly have used some construction like
yours, but the Government had not then a single iron vessel, and did
not seem disposed to urge the enquiry. You, under happier auspices,