pure mathematics that he ultimately won his greatest fame, yet he
always maintained and maintained with justice, that he had ample
claims to the title of an astronomer. In his later years he set
forth this position himself in a rather striking manner. De Morgan
had written commending to Hamilton's notice Grant's "History of
Physical Astronomy." After becoming acquainted with the book,
Hamilton writes to his friend as follows:--

"The book is very valuable, and very creditable to its composer. But
your humble servant may be pardoned if he finds himself somewhat
amused at the title, `History of Physical Astronomy from the Earliest
Ages to the Middle of the Nineteenth Century,' when he fails to
observe any notice of the discoveries of Sir W. R. Hamilton in the
theory of the 'Dynamics of the Heavens.'"

The intimacy between the two correspondents will account for the tone
of this letter; and, indeed, Hamilton supplies in the lines which
follow ample grounds for his complaint. He tells how Jacobi spoke of
him in Manchester in 1842 as "le Lagrange de votre pays," and how
Donkin had said that, "The Analytical Theory of Dynamics as it exists
at present is due mainly to the labours of La Grange Poisson,
Sir W. R. Hamilton, and Jacobi, whose researches on this subject
present a series of discoveries hardly paralleled for their elegance
and importance in any other branch of mathematics." In the same
letter Hamilton also alludes to the success which had attended the
applications of his methods in other hands than his own to the
elucidation of the difficult subject of Planetary Perturbations.
Even had his contributions to science amounted to no more than these
discoveries, his tenure of the chair would have been an illustrious
one. It happens, however, that in the gigantic mass of his