So great a personality as Hamilton has naturally gathered around itself much biographical interest. The intimacy between Hamilton and Wordsworth has given many interesting pages to Mr. Graves’ book, and how intimate the friendship became may be conjectured from the account of their first meeting. We are told how Hamilton walked back with Wordsworth to see him home after a delightful evening, and how Wordsworth then turned to see Hamilton back, and how the process was repeated I know not how often. It appears that Hamilton submitted his poetic effusions to his friend, and they were returned with gentle criticism, though with an occasional admission by Wordsworth that the mathematician’s verses possessed genuine feeling. Then there is the visit of Wordsworth to Dunsink, where to this day a beautiful shady walk bears his name. Hamilton enjoyed the privilege of intimacy with many cultivated intellects. He knew Coleridge; with Sir John Herschel he was in frequent communication; and he had many lady correspondents, including Maria Edgeworth. The bulk of Hamilton’s scientific correspondence was with the late Professor De Morgan, a man whose intellectual endowments were of such a different type to those of Hamilton, that, except in being both mathematicians, they had but little in common. On the death of Hamilton, De Morgan writes to Sir John Herschel (Sept. 13, 1865):-- “W. R. Hamilton was an intimate friend whom I spoke to once in my life--at Babbage’s about 1830; but for 30 years we have corresponded. I _saw_ him a second time at the dinner you got at the Freemason’s when you came from the Cape, but I could not get near enough to speak.”[108] The Observatory had the usual equipment of a transit instrument, a circle, and an equatorial, but no further additions were made to the instruments during the long sojourn of Hamilton. Observations were made by the assistant, Mr. Thomson, who, after a life passed in the service, retired in 1874, and lived a few years to enjoy the pension conferred on him by the Board. Just before Sir W. Hamilton’s death an important donation was received by the College. I shall here mention the circumstances under which it was made. The particulars were related to me partly by the donor himself, and partly by the late Earl of Rosse. The chief incidents in the narrative may be found in the life of De Morgan[109] to which I have already referred.