But however well-founded these observations may be, we agree in opinion with M. Daunou,[101] “that they are not sufficient to establish a new system, and we must regard the system of Newton as a great fact in the history of chronological science, and as confirming the observation of Varro, that the stage of history does not commence till the first Olympiad.” Among the chronological writings of Sir Isaac Newton we must enumerate his _letter to a person of distinction who had desired his opinion of the learned Bishop Lloyd’s hypothesis concerning the form of the most ancient year_. This hypothesis was sent by the Bishop of Worcester to Dr. Prideaux. Sir Isaac remarks, that it is filled with many excellent observations on the ancient year; but he does not “find it proved that any ancient nations used a year of twelve months and 360 days without correcting it from time to time by the luminaries, to make the months keep to the course of the moon, and the year to the course of the sun, and returns of the seasons and fruits of the earth.” After examining the years of all the nations of antiquity, he concludes, “that no other years are to be met with among the ancients but such as were either luni-solar, or solar or lunar, or the calendars of these years.” A practical year, he adds, of 360 days is none of these. The beginning of such a year would have run round the four seasons in seventy years, and such a notable revolution would have been mentioned in history, and is not to be asserted without proving it.[102] CHAPTER XVI. _Theological Studies of Sir Isaac—Their Importance to Christianity— Motives to which they have been ascribed—Opinions of Biot and Laplace considered—His Theological Researches begun before his supposed Mental Illness—The Date of these Works fixed—Letters to Locke—Account of his Observations on Prophecy—His Historical Account of two notable Corruptions of Scripture—His Lexicon Propheticum—His Four Letters to Dr. Bentley—Origin of Newton’s Theological Studies—Analogy between the Book of Nature and that of Revelation._