"For sounds like thunder, and coruscations like lightning, may be made in the air, and they may be rendered even more …"

"Mix together saltpetre, luru vopo vir con utriet [powdered charcoal], and sulphur, and you will make thunder and ligh…"

"Prudens quaestio dimidium scientiae."

"Argument is conclusive... but... it does not remove doubt, so that the mind may never rest in the sure knowledge of t…"

"There are in fact four very significant stumbling blocks in the way of grasping the truth, which hinder every man how…"

"For the things of this world cannot be made known without a knowledge of mathematics. For this is an assured fact in …"

"Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain, nor does it…"

"If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the…"

"I shall draw... a figure (which all these matters are made clear as far as possible on a surface, but the full demons…"

"Oh how delightful is the taste of wisdom to those who are thus steeped in it from its very fount and origin. They who…"