The _Principia_ convinced its readers that the laws of mechanics, discovered by experiment on the earth, were operative throughout the solar system. It was reserved for the nineteenth century to extend the reign of law to other celestial phenomena. Newton and his successors had proved that the law of gravity extends through all parts of space where observations are possible. That the sun, stars, and planets are constituted of similar materials was generally believed; and this has now been confirmed by the use of the spectroscope which has enabled us to calculate the temperature of gaseous stars, and specify the chemical elements comprised in them. Thus the composition of far-distant suns has been reduced to problems to be settled in our laboratories. The scientific world, however, in admitting the validity of the theory of universal gravity had implicitly accepted the principle that the reign of law, as investigated on the earth, extends throughout the universe. Thus the daring which permits us, living on a medium-sized planet attached to one of the smaller suns, to analyse the universe is, I venture to say, the direct outcome of the genius of Newton as displayed in his _Principia_. CHAPTER XIV. ISAAC NEWTON ON UNIVERSITY STUDIES. Among the Portsmouth papers in the University Library at Cambridge[33] is a memorandum by Isaac Newton, drawn up, I conjecture, towards the close of the seventeenth century, on the organization of the studies and on the discipline of the University. Conditions then differed so widely from those now in force that the value of the memorandum is only historical, but notwithstanding this, its interest is considerable. I have no reason to suppose that it was formally brought before the regent or the non-regent house, and possibly the plan never got beyond discussion by a few friends. I have modernized the spelling, made the use of capitals uniform, allowed myself to break paragraphs, and sometimes inserted punctuation or altered it--otherwise the paper is as originally written. I give it without further comment. _Newton's Memorandum._ "Undergraduates to be instructed by a Tutor, a Humanity Lecturer, a Greek Lecturer, a Philosophy Lecturer, and a Mathematic Lecturer. "The Tutor to read logic, ethics, the globes and principles of geography and chronology in order to understand history, unless the Lecturers have time for any of these things. "The Humanity and Greek Lecturers to set tasks in Latin and Greek authors once a day to the first year, and once a week to the rest; and to examine diligently and instruct briefly; and to punish by exercises such faults as concern lectures; and to appoint the reading of the best historians.