At the outset it is of some importance to understand clearly the nature of that system of Chronology which is gathered from the Bible. Nowhere in the Sacred Text is the age of the human race explicitly set forth. But various data are found scattered here and there through the historical narrative, which afford us sufficient materials to compute the years that elapsed from the Creation of Adam to the Birth of Christ. Unfortunately, however, these data are in some respects obscure, and in some respects uncertain. And thus it has come to pass that many different systems of Chronology have come into vogue, even amongst those who profess to be guided entirely by the authority of the Bible. The whole period may be conveniently divided into two parts;--from the Creation of Adam to the Call of Abraham; and from the call of Abraham to the Birth of Christ. As regards the latter interval, the difference of opinion between Chronologists is not very substantial; the length of the period may be roughly set down at about 2,000 years. But in the computation of the former interval a very wide difference prevails, arising from a diversity of reading in the earliest versions of the Pentateuch. The materials for the computation are derived from two genealogical lists, one extending from Adam to Noah,[106] the other from Noah to Abraham.[107] In these lists we have not only the direct line of descent from father to son, extending through the whole period in question, but, moreover, we have the age of each individual member of the genealogy at the time when the next in succession was born. As, for example:--“Adam lived _a hundred and thirty years, and begot a son_ to his own image and likeness, and called his name Seth. And the days of Adam, after he had begot Seth, were eight hundred years: and he begot sons and daughters. And all the time that Adam lived came to nine hundred and thirty years, and he died. Seth also lived _a hundred and five years, and begot Enos_. And Seth lived, after he begot Enos, eight hundred and seven years, and begot sons and daughters. And all the days of Seth were nine hundred and twelve years, and he died. And Enos lived _ninety years, and begot Cainan:_”[108] and so on. Now it is plain, according to this statement, that from the Creation of Adam to the birth of Seth was a hundred and thirty years; to the birth of Enos, a hundred and thirty, more a hundred and five years; to the birth of Cainan, a hundred and thirty, more a hundred and five, more ninety years. And in this way, following the genealogies of the Book of Genesis, we may easily compute the time from the Creation of Adam to the Birth of Abraham. Adding seventy-five years to this period, we reach the epoch known as the Call of Abraham; for we are told that “Abraham was seventy and five years old when he went forth from Haran.”[109]