In 1618 (8th March) John Kepler came upon the discovery of the law connecting the mean distances of the planets with the periods of their revolution about the sun, that the squares of the times vary as the cubes of the distances. And he writes, “It is now eighteen months since I got the first glimpse of light,—three months since the dawn,—very few days since the unveiled sun, most admirable to gaze on, burst out upon me. Nothing holds me. I will indulge in my sacred fury. I will triumph over mankind by the honest confession that I have stolen the golden vases of the Egyptians[227] to build up a tabernacle for my God far away from the confines of Egypt. If you forgive me, I rejoice; if you are angry, I can bear it: the die is cast; the book is written; to be read either now or by posterity. I care not which. It may well wait a century for a reader, since God has waited six thousand years for an observer like myself.” In books I have the history or the energy of the past. Angels they are to us of entertainment, sympathy and provocation. With them many of us spend the most of our life,—these silent guides,—these tractable prophets, historians, and singers, whose embalmed life is the highest feat of art; who now cast their moonlight illumination over solitude, weariness and fallen fortunes. You say, ’tis a languid pleasure. Yes, but its tractableness, coming and going like a dog at our bidding, compensates the quietness, and contrasts with the slowness of fortune and the inaccessibleness of persons. You meet with a man of science, a good thinker or good wit,—but you do not know how to draw out of him that which he knows. But the book is a sure friend, always ready at your first leisure,—opens to the very page you desire, and shuts at your first fatigue,—as possibly your professor might not. It is a tie between men to have read the same book, and it is a disadvantage not to have read the book your mates have read, or not to have read it at the same time, so that it may take the place in your culture it does in theirs, and you shall understand their allusions to it, and not give it more or less emphasis than they do. Yet the strong character does not need this sameness of culture. The imagination knows its own food in every pasture, and if it has not had the Arabian Nights, Prince Le Boo, or Homer or Scott, has drawn equal delight and terror from haunts and passages which you will hear of with envy.