SKETCH OF PROFESSOR BENJAMIN PEIRCE. 691 



theories. Mental notions can aid ns only as they are reflections of na- 

 ture. Even scientific hypotheses have but a relative validity. In time, 

 as in space, the extent of knowledge follows a law analogous to the 

 law of spherical diffusion. It has been held that the record of any 

 historic event is wholly invalidated by the lapse of sufficient time ; 

 much more is this true of future prediction. The base-line of our 

 knowledge is sufficient but for a limited survey. The very distant 

 future has no mental parallax. 



We have seen every far-reaching theory become obsolete ; and 

 there is no reason to suppose that, at the present time, we shall be more 

 successful. There is but one course that it is safe to pursue, namely, 

 to be content to let insoluble problems remain as such not attempt- 

 ing any mental theory concerning them and confine ourselves to those 

 problems that may offer some probability of solution, with the assur- 

 ance that, however far the boundaries of knowledge may be extended, 

 each successful solution will enlarge the horizon of the unknown be- 

 yond. 



SKETCH OF PROFESSOK BENJAMIK PEIRCE. 



THIS illustrious American mathematician and astronomer died in 

 Boston, October 6, 1880, in the seventy-second year of his age. He 

 was born in Salem, Massachusetts, April 4, 1809. He was graduated 

 at Harvard College at the age of twenty. His father was a graduate 

 of the same institution, and died its librarian. He was appointed tutor 

 in 1831, University Professor of Mathematics and Natural Philosophy 

 in 1833, and Perkins Professor of Astronomy and Mathematics in 

 1842, and was directly connected with the faculty of the college for 

 forty-nine years. He was a member of all the learned societies in this 

 country and in Europe, was elected Fellow of the Royal Society of 

 England in 1857, and in 1867 received the degree of LL. D. from Har- 

 vard University. 



We take the liberty of quoting from that excellent periodical, 

 " The Harvard Register," for May, 1880 (to the courtesy of whose 

 editor we are also indebted for the excellent likeness herewith pre- 

 sented), the following account of Professor Peirce's character and 

 work, written, it will be observed, before his death, by Dr. Thomas 

 Hill, ex-President of Harvard University : 



" From 1836 to 1846 he issued a series of text-books on geometry, 

 trigonometry, algebra, and 'curves, functions, and forces.' They were 

 so full of novelties that they never became widely popular, except, 

 perhaps, the trigonometry ; but they have had a permanent influence 

 upon mathematical teaching in this country ; most of their novelties 

 have now become commonplaces in all text-books. The introduction 



