In Egypt remains are found, as we shall see, which carry the history of civilisation back to something like 5000 B.C., and in Mesopotamia the latest finds are believed to extend the record by yet another two thousand years. Man then existed in a state of high civilisation at a period antedating the Christian era by about twice the length of time formerly admitted for the age of earth itself. How much more ancient the remains of barbaric man, as preserved in the oldest caves, may be, it would be but vague guess work and serve no useful purpose, to attempt to estimate. History proper, as usually conceived, is concerned only with the doings of civilised man; and, indeed, in one sense, such a restricted view is absolutely forced upon the historian, for it is only civilised man who is able to produce records that are preserved through the ages in such manner as to tell a connected story to after generations. The arrow-heads and charred sticks of the stone age of man are indeed proofs that this man existed, and that he led his certain manner of life, some clear intimations as to which are given by these mementoes; but they point to no path by which we may hope to follow the precise history of those succeeding generations by which the man of the stone age was connected with, for example, the builder of the Egyptian Pyramids. We can, indeed, trace in general terms the course of human progress. We know that from using rough stone implements chipped into shape, man came finally to acquire the art of polishing stones by friction, thus making more finished implements. We know that later on he learned to smelt metals, marvellous achievement that it was; and when this had been accomplished, we may suppose that he pretty rapidly developed cognate arts that led to higher civilisation. Reasoning from this knowledge, we speak of the palæolithic or rough stone age, of the neolithic or polished stone age, of the age of bronze, and finally of the age of iron, as representing great epochs in human progress. But it is only in the vaguest terms that we can connect one of these ages with another, and any attempt at a definite chronology in relation to them utterly fails us. This would not so much matter if we were sure in any given case that we were tracing the history of the same individual race through the successive periods; but, in point of fact, no such unity of race can be predicated. There is every reason to believe that each and every race that ever attained to higher civilisation passed through these various stages, but the familiar examples of the American Indians, who were in the rough stone age when their continent was discovered by Columbus, and of the African and Australian races, who, even now, have advanced no farther, illustrate the fact that different races have passed through these various stages of development in widely separated periods of time, and take away all certainty from any attempts to compute exact chronologies. CHAPTER V