In his _Le Préhistorique_ M. de Mortillet attempted to determine how far distant was the epoch when _Homo sapiens_ first appeared on the earth, by estimating the rate of progression of blocks which were carried by former ice fields, as he had observed them in Switzerland with Agassiz. His conclusion was that more than two hundred thousand years had elapsed since that event. In 1894 M. de Mortillet proposed in the Société d'Anthropologie an important reform in chronology. Pointing out the inconvenience of using several different eras, such as the Foundation of Rome, the Flight of Mohammed, and the Proclamation of the French Republic, he suggested that ten thousand years before the Christian era be adopted as a general starting point. This would include all Egyptian chronology as known at the present day, and would leave five thousand years at the disposal of future discoverers. "A spirit always youthful, a man of progress," says Dr. Capitan in his eulogy, "our dear master kept himself fully in the current with all work relating to prehistoric archæology. He knew how to profit by whatever would contribute to perfect his own work. He therefore, on different occasions, modified his classification so as to keep it up to date, realizing that a classification is an admirable instrument of study, which ought to go through the same evolution as the science to which it is applied." This high quality of his mind appears clearly in his last book, published in 1897--_Formation de la Nation française_ (Formation of the French Nation). This book comprised the substance of his lectures of the term 1889-'90. In publishing it he disavowed all intention of producing a new history of France. There were enough of these in all shapes and sizes, written in the most varied styles, with diverse tendencies, and from the most different points of view, and there were some most excellent works among them, particularly that of M. Henri Martin, which seemed to him to contain all the historical information known. But all these histories, even that of Henri Martin, although he had been president of the Anthropological Society of Paris, appeared to M. de Mortillet to be at fault in their starting point. They gave too much place in their beginnings to the legendary and the imaginary, and not enough to natural history and palæethnology. It was M. de Mortillet's purpose to follow an inverse method--to regard direct observation alone; and he would rest only on the impartial and precise discussion of texts and facts. "Texts, documents, and facts," he said, "become more and more rare as we go back in time. I shall collect and examine them with the greatest care in order to make our origins as clear as possible, and to enlarge the scale of our history. I shall appeal in succession to all the sciences of observation, and when I have recourse to the texts, I shall subject them to the closest criticism and the most complete analysis." The