“The history of mankind, of nations and of nature, natural science, mathematics and his own experience were the wellsprings which animated his lectures and his everyday life. He was never indifferent to anything worth knowing. No intrigue, no sectional interests, no advantage, no desire for fame ever possessed the slightest power to counteract his extension and illumination of truth. He encouraged and gently compelled people to think for themselves: despotism was alien to his nature.”