Truly man is the king of beasts, for his brutality exceeds them. We live by the death of others. We are burial places. - Leonardo da Vinci

Where there is most power of feeling, there of martyrs is the greatest martyr.

Among all the studies of natural causes and reasons Light chiefly delights the beholder; and among the great features of Mathematics the certainty of its demonstrations is what preeminently (tends to) elevate the mind of the investigator. Perspective, therefore, must be preferred to all the discourses and systems of human learning. In this branch [of science] the beam of light is explained on those methods of demonstration which form the glory not so much of Mathematics as of Physics and are graced with the flowers of both.

Although attempting to bridge the gulf which separated the real from the unreal, he refused to treat the latter supernaturally. That mystery which lesser minds found in the occult, he saw in nature all about him. He denied the existence of spirits, just as he urged the foolishness of the will-o'-the-wisps of former ages, — alchemy and the black art.