Clippings

I now saw a world leap to life before my eyes because I could explore it, and that meant not going home when school was out, but wandering, watching, asking, talking. Had I gone home to eat my plate of greens, Granny would not have allowed me out again, so the penalty I paid for roaming was to forfeit my food for twelve hours. I would eat mush at eight in the morning and greens at seven or later at night. To starve in order to learn about my environment was irrational, but so were my hungers. With my books slung over my shoulder, I would tramp with a gang into the woods, to rivers, to creeks, into the business district, to the doors of poolrooms, into the movies when we could slip in without paying, to neighborhood ball games, to brick kilns, to lumberyards, to cottonseed mills to watch men work. There were hours when hunger would make me weak, would make me sway while walking, would make my heart give a sudden wild spurt of beating that would shake my body and make me breathless; but the happiness of being free would lift me beyond hunger, would enable me to discipline the sensations of my body to the extent that I could temporarily forget.

While in Berlin, Euler was asked to provide instruction in elementary science to the Princess of Anhalt Dessau. The result was a multi-volume masterpiece of exposition, subsequently published as Letters of Euler on Different Subjects in Natural Philosophy Addressed to a German Princess. This compilation of over 200 “letters” introduced subjects as diverse as light, sound, gravity, logic, language, magnetism, and astronomy. In the course of the work, Euler explained why it is cold atop a high mountain in the tropics, why the moon looks larger when it rises, and why the sky is blue. He ranged further afield when he discussed the origin of evil, the conversion of sinners, and the intriguing topic of “Electrization of Men and Animals.”

Writing about vision in a “letter” dated August 1760, Euler began with these words: “I am now enabled to explain the phenomena of vision, which is undoubtedly one of the greatest operations of nature that the human mind can contemplate.” The poignancy of this remark, coming as it did from a partially — and soon to be totally — blind author, is striking. But Euler was not one to let personal misfortune interfere with his attitude toward the wonders of Nature.

Letters to a German Princess became an international hit. The work was translated into a host of languages across Europe and eventually published (in 1833) in the United States. In the preface of the American edition, the publisher gushed over Euler’s expository skill in guaranteeing that

the delight of the reader is, at every step, commensurate with her improvement, and each succeeding acquisition of knowledge becomes a source of still increasing gratification.

In the end, this was Euler’s most widely read book. It is not always the case that a scholar working at the very frontier of research can step back to write a treatise accessible to the layman, but this Euler surely did. Letters to a German Princess remains to this day one of history’s finest examples of popular science.

But the great security against a gradual concentration of the several powers in the same department consists in giving to those who administer each department the necessary constitutional means and personal motives to resist encroachments of the others. The provision for defense must in this, as in all other cases, be made commensurate to the danger of attack. Ambition must be made to counteract ambition. The interest of the man must be connected with the constitutional rights of the place. It may be a reflection on human nature that such devices should be necessary to control the abuses of government. But what is government itself but the greatest of all reflections on human nature? If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficult lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions.