subject of the Papers set in the
Smith's Prizes Examination. In this letter, as on former occasions, he
objected much to the large number of questions in "purely idle
algebra, arbitrary combinations of symbols, applicable to no further
purpose." And in particular he singled out for comment the following
question, which was one of those set, "Using the term circle as
extending to the case where the radius is a pure imaginary, it is
required to construct the common chord of two given circles." This
drew forth as usual a rejoinder from Prof. Cayley, who wrote
enclosing a solution of his problem, but not at all to Airy's
satisfaction, who replied as follows: "I am not so deeply plunged in
the mists of impossibles as to appreciate fully your explanation in
this instance, or to think that it is a good criterion for University
candidates."

Of private history: On Jan. 21st he returned from Playford.--On March
22nd he attended the funeral of his sister at Little Welnetham near
Bury St Edmunds: Miss Elizabeth Airy had lived with him at the
Observatory from shortly after his appointment.--For about a week at
the end of April he was visiting Matlock, Edensor, and Buxton.--From
June 14th to July 18th he was staying at Portinscale near Keswick.--He
was at Playford for two or three days in October, and went there again
on Dec. 23rd for his usual winter holiday.

The following letter, relating to the life of Thomas Clarkson, was
written to Dr Merivale, Dean of Ely, after reading the account in the
"Times" of October 10th of the unveiling of a statue of Clarkson near
Ware:

ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1879, October 11_.

DEAR SIR,

Pardon my intrusion on you, in reference to a transaction which has
greatly interested me--the honour paid by you to the memory of Thomas
Clarkson. With very great pleasure I have heard of this step: and I
have also been much satisfied with the remarks on it in the "Times." I
well remember, in Clarkson's "History of the Abolition," which I read
some 60 years ago, the account of the circumstance, now commemorated
by you, which determined the action of his whole subsequent life.

It is not improbable that, among those who still remember Clarkson, my
acquaintance with him began at the earliest time of all. I knew him,
intimately, from the beginning