19 SEPTEMBER 1885, Page 16

THE LATE SIR W. R. HAMILTON.

ET0 THE EDITOR OF THE " SPECTATOR."]

Sia,—As the author of the "Biography of Sir W. R. Hamilton," I am anxious that readers of the Spectator who have taken note of Dr. Ingleby's letter in your issue of the 5th inst., and may not see my book, should not impute to me a disposition to do less than justice to my friend, Professor Sylvester. A reference to several passages in my second volume would acquit me of this ; and its last paragraph would prove my appreciation of his generous estimate of Hamilton's discovery, and that I had not failed to record his own in the same direction, though, doubt- less, Dr. Ingleby is much more qualified than I am to indicate. its value.

Calling attention to the fact that neither I nor my kind reviewer intended to give an exhaustive list of the mathe- maticians who have cultivated Quaternions, I am sure he will be willing I should here state that I should have been pleased had he added to the names mentioned by him not only Sylvester, but also those of Clerk Maxwell and Henry Smith. The former has been cited by me as using and recommending the Calculus ; the latter has given an important judgment on the subject in his Introduction to "The Mathematical Papers" of