"Comparatively few of the propositions and proofs in the Elements are his own discoveries. In fact, the proof of the "Theorem of Pythagoras" is the only one directly ascribed to him."

“The Elements has been considered as offering models of scrupulously rigorous demonstrations. It is certainly true that in point of rigour it compares favourably with its modern rivals; but when examined in the light of strict mathematical logic, it has been pronounced by C.S. Peirce to be "riddled with fallacies." The results are correct only because the writer's experience keeps him on his guard.”

“''An Introduction to the Modern Theory of Equations”

“A History of the Conceptions of Limits and Fluxions in Great Britain: from Newton to Woodhouse”

“On the History of Gunter's Scale and the Slide Rule During the Seventeenth Century”

“In 1735 the solving of an astronomical problem, proposed by the Academy, for which several eminent mathematicians had demanded several months' time, was achieved in three days by Euler with aid of improved methods of his own... With still superior methods this same problem was solved by the illustrious Gauss in one hour.”

“My quotations from Newton suggest the motive which induced him to take a stand against the use of hypotheses, namely, the danger of becoming involved in disagreeable controversies. ...Newton could no more dispense with hypotheses in his own cogitations than an eagle can dispense with flight. Nor did Newton succeed in avoiding controversy.”