Where the transition was made from the Stone Age to the Age of Bronze, it apparently occurred in some cases by degrees, and peacefully; but sometimes by the incoming of an invading people more advanced. It should be observed that the lines of division between these periods are not sharply drawn: implements of stone continued to be used after the Bronze and even the Iron periods had been introduced. Nor were these several ages in one region contemporaneous with like conditions in every other. Moreover, it is not possible to find in all countries once civilized proofs of a passage through these successive eras. In Egypt, the evidences of a Stone Age are scanty. The most ancient human remains show that man in his physical characteristics was on a level with man at present. _Dr. Daniel Wilson_, speaking of the age of the Flint-folk, says: "It is of no slight importance to perceive that the interval which has wrought such revolutions in the earth" [involving great geological changes and mutations of climate] "as are recorded in the mammaliferous drift, shows man the same reasoning, tentative, and inventive mechanician, as clearly distinguished then from the highest orders of contemporary life of the Elephantine or Cave periods, as he is now from the most intelligent of the brute creation.... The oldest art-traces of the paleotechnic men of central France not only surpass those of many savage races, but they indicate an intellectual aptitude in no degree inferior to the average Frenchman of the nineteenth century." (_Prehistoric Man_, pp. 33, 34.) Literature.--Wilson, _Prehistoric Man_, etc. (2 vols., 1876); Joly, _Man before the Metals_ (1883); Keary, _The Dawn of History_. The writings of E. B. Tylor, _Primitive Culture_ (2 vols.), _Anthropology, Early History of Mankind_; his Art. _Anthropology, Encycl. Britt_.; Lubbock's _Prehistoric Times_, and his _Origin of Civilization_; Argyll, _The Unity of Nature _(1884); J. Geikie, _Prehistoric Europe_ (1881); Lyell, _The Antiquity of Man_; W. E. Hearn, _The Aryan Household_; L. H. Morgan, _Ancient Society_. THE ANTIQUITY OF MAN.--Science does not furnish us with the means of fixing the date of the first human inhabitants of the earth. But its various departments of investigation concur in pronouncing the interval between the creation of man and the present to be far longer than the traditional opinion has assumed. For the growth of language and its manifold ramifications; for the development of the different races of mankind, physically considered; for the geological changes since the beginning of the Stone Age in the regions where its relics are uncovered; for the rise of the most ancient civilization in Egypt as well as in Babylon and China,--it is thought that periods of very long duration are indispensable.