It was ten years after the discovery that the great volume appeared
under the title of "Lectures on Quaternions," Dublin, 1853. The
reception of this work by the scientific world was such as might have
been expected from the extraordinary reputation of its author, and
the novelty and importance of the new calculus. His valued friend,
Sir John Herschel, writes to him in that style of which he was a
master:--

"Now, most heartily let me congratulate you on getting out your
book--on having found utterance, ore rotundo, for all that labouring
and seething mass of thought which has been from time to time sending
out sparks, and gleams, and smokes, and shaking the soil about you;
but now breaks into a good honest eruption, with a lava stream and a
shower of fertilizing ashes.

"Metaphor and simile apart, there is work for a twelve-month to any
man to read such a book, and for half a lifetime to digest it, and I
am glad to see it brought to a conclusion."

We may also record Hamilton's own opinion expressed to Humphrey
Lloyd:--

"In general, although in one sense I hope that I am actually growing
modest about the quaternions, from my seeing so many peeps and vistas
into future expansions of their principles, I still must assert that
this discovery appears to me to be as important for the middle of the
nineteenth century as the discovery of fluxions was for the close of
the seventeenth."

Bartholomew Lloyd died in 1837. He had been the Provost of Trinity