We can never be too grateful for the persevering labours of those who have carried on these researches in every corner of Europe; their deserts are all the greater from the fact that they could never count upon those agreeable surprises which come now and then to reward excavators on the sites of ancient and historic cities. Their chances are small of finding those objects of art which, by their beauty and elegance, repay any amount of toil and expense. The remains which they bring to light have little to say to our æsthetic perceptions; they repeat a few types with an extreme monotony; but, on the other hand, they carry our thoughts back to a point far nearer the cradle of our race than the myths of early history or even the monumental remains of Egypt and Chaldæa. They cast some slight illumination upon those distant ages of which humanity has preserved no recollection. They people with unknown multitudes those remote epochs into which scientific curiosity had, but yesterday, no desire to penetrate. There can be in all this no real question of chronology, but when from the sands of Abbeville or the caverns of Perigord we dig up the first flint implements or those fragments of bone, of ivory, of reindeer horn, which have preserved to us the first attempts made by man to copy the outlines of living beings, it takes us far beyond those days of which our only knowledge comes from vague tradition, and still farther beyond those centuries which saw the first struggling dawn of history. * * * * * We have, then, decided not to embark upon these questions of prehistoric art, because, as the title which we have chosen declares, we propose to write a _history_, and the word history, when the human race is in question, implies established relations between certain groups of facts and certain portions of time, measured at least with something approaching to probable truth.