for the fact that the method has not become more familiar to students
of the higher mathematics. An eminent professor has complained that
Hamilton's essay on dynamics was of such an extremely abstract
character, that he found himself unable to extract from it problems
suitable for his examination papers.

The following extract is from a letter of Professor Sylvester to
Hamilton, dated 20th of September, 1841. It will show how his works
were appreciated by so consummate a mathematician as the writer:--

"Believe me, sir, it is not the least of my regrets in quitting this
empire to feel that I forego the casual occasion of meeting those
masters of my art, yourself chief amongst the number, whose
acquaintance, whose conversation, or even notice, have in themselves
the power to inspire, and almost to impart fresh vigour to the
understanding, and the courage and faith without which the efforts of
invention are in vain. The golden moments I enjoyed under your
hospitable roof at Dunsink, or moments such as they were, may
probably never again fall to my lot.

"At a vast distance, and in an humble eminence, I still promise myself
the calm satisfaction of observing your blazing course in the
elevated regions of discovery. Such national honour as you are able
to confer on your country is, perhaps, the only species of that
luxury for the rich (I mean what is termed one's glory) which is not
bought at the expense of the comforts of the million."

The study of metaphysics was always a favourite recreation when
Hamilton sought for a change from the pursuit of mathematics. In the
year 1834 we find him a diligent student of Kant; and, to show the