Turning now from geological evidence to that founded upon other observations, as to the length of time man has been an inhabitant of the earth, perhaps one of the most interesting discoveries was that of the Tumuli or mounds of shells of such animals as the oyster, cockle, limpet, etc., and, along with this, the bones of birds, wild animals, and fish, together with stone implements and rude pottery. These kitchen-middens were first discovered in Denmark, but they have since been found in many countries where savages have lived along the coast. In many of the Swiss lakes, such as Zurich and Neufchatel, there have been found piles driven into the ground, around which, in dredging, human bones, as well as stone implements, have been brought up, and which are now known to have been the dwelling-places and remains of prehistoric peoples, who located in this manner so as to protect themselves from prowling wild animals and from their savage neighbors. From the amount and character of these deposits, we are forced to assume that the habitations were used for a long period, and from geological computation of the time required to deposit the silt around these piles in the Swiss Lake-villages, and from the similarity of the remains in the Danish peat-mosses and the kitchen-middens no period could be assigned to their antiquity of less than seven thousand years. Our earliest record of historic man is found in the Valley of the Nile, where we can say with certainty that, over seven thousand years ago, there existed a high state of civilization under the old Egyptian Empire. Menes was the first recorded king who sat on the throne, and during the six dynasties of kings which composed this period, we see the rise to supremacy of Memphis, the building of the pyramids, the accumulation of a varied and extensive literature, and the perfection of the industrial and fine arts. In fact, so faithfully and indestructibly were the lines of human faces reproduced upon stone and other materials, that, at this day, we have no difficulty in identifying the different races of men from their resemblance at the present time. Menes, himself, carried to completion the great engineering feat of turning the course of the Nile so as to obtain a site for his capital, at Memphis. His successor was not only a patron but a practitioner of the art of medicine. From the monuments and papyri of the great tombs of Ghizeh and Sakkara, we have learned so much of the social and political life of Egypt at this period through the deciphering of the Rosetta stone by Champollion, that we may be said to have a very accurate knowledge of mankind, as his existence was conditioned in Egypt from four to five thousand years before the beginning of our present era. From Memphis, the seat of the government first shifts to Heracleopolis, and then to Thebes, and, during these changes, we see Egypt go back into the night of semi-barbarism