< His mathematical studies. >

He was (vide his life) 40 yeares old before he looked on geometry; which happened accidentally. Being in a gentleman's library in ..., Euclid's Elements lay open, and 'twas the 47 El. libri I. He read the proposition. By G—,' sayd he, 'this is impossible!' So he reads the demonstration of it, which referred him back to such a proposition; which proposition he read. That referred him back to another, which he also read. Et sic deinceps, that at last he was demonstratively convinced of that trueth. This made him in love with geometry.

I have heard Sir Jonas Moore (and others) say that 'twas a great pity he had not began the study of the mathematics sooner, for such a working head would have made great advancement in it. So had he donne, he would not have layn so open to his learned mathematicall antagonists. But one may say of him, as one (quaere who) sayes of Jos. Scaliger, that where he erres, he erres so ingeniosely, that one had rather erre with him then hitt the mark with Clavius. I have heard Mr. Hobbes say that he was wont to draw lines on his thigh and on the sheetes, abed, and also multiply and divide. He would often complain that algebra (though of great use) was too much admired, and so followed after, that it made men not contemplate and consider so much the nature and power of lines, which was a great hinderance to the groweth of geometrie; for that though algebra did rarely well and quickly, and easily in right lines, yet 'twould not bite in solid (I thinke) geometrie. Quod N.B.

Memorandum—After he began to reflect on the interest of the king of England as touching his affaires between him and the parliament, for ten yeares together his thoughts were much, or almost altogether, unhinged from the mathematiques; but chiefly intent on his De Cive, and after that on his Leviathan: which was a great putt-back to his mathematicall improvement—quod N.B.—for in ten yeares' (or better) discontinuance of that study (especially) one's mathematiques will become very rusty.