Whence comes this power? When and how did it arrive? That we do not know. For the early beginnings of man we can only grope among the relics of his progress which he has left for the speculation of his more intelligent descendants, in the shape of the rude implements and dwellings which he used in the childhood of the race. From time to time actual remains of early man are found buried among the uppermost strata, and from them we can make some guesses at his age. Virtually three links have been found in the chain of human ancestry. The earliest is represented by the "Trinil Man" of Java, found by Dubois in 1890, and named the _Pithecanthropos erectus_, in reference to its likeness both to man as we know him and to the great anthropoid apes, although it had a much more erect carriage than any of them. This relic, man or some other creature as it may have been, stands midway between the chimpanzee and the more typical "Neandarthal Man," the skull of which was found in a cave of the Neander Valley, near Dusseldorf, in 1856. Thirty years later the skulls of the "Spy men" of the same type as this were found in Belgium. This type lived in what we call the early Stone Age, and was a low type of meat-eating hunter. The next higher type, the third type of man, is that identified with what geologists and anthropologists call the "Gibraltar skull," from the place where the skull was found. But all we know of these types of man we must judge from their skulls and from the stone implements and the animals found near them. The skulls of primitive men and of modern men show a certain difference in shape. If we take two skulls, that of a man and a monkey, and draw a line from the region just over the nose to the place at the back of the skull just above where it joins the backbone, there is left above the line a great dome in the human skull, whereas in the monkey the place left above is much flatter and much shallower. Now the skull of the _Pithecanthropos erectus_ found in Java resembles the monkey's skull in this shallowness; and the skulls of the Neandarthal and the Spy men also had shallower brain-pans than the men of to-day. They may, therefore, be either different creatures or they may merely have had smaller brains. We can only say that the creature called Man suddenly appears among the lower animals with a brain some five or six times the bulk (in proportion to his size and weight) of that of any surviving ape. Great as is the difference, it is one of the most curious facts in the history of man's development that the bulk of his brain does not seem to have continued to increase in any very marked degree since the early Ages of Stone.