_Note the progressive lessening of brow ridge and receding chin and the increase in the height of forehead and vault._ Pithecanthropus robustus _was found in the same general area as_ Pithecanthropus erectus, _or Java man._ (_Robustus, after Weidenreich, 1946; Neanderthal, after McGregor, 1926; Cro-Magnon, after Verneau, 1906._)] [Illustration: MAN’S FIRST SPEAR POINTS _Two views of a flake of flint that has been chipped on one face and retouched along the edges by a Neanderthal man. To remove the tiny lateral chips, he probably held it with the smoother side against a chunk of wood, and struck small and careful blows with a hammerstone (as shown at the bottom of page 91). Acheulean man may have used this technique in making the best of his hand axes. (After Mortillet, 1881.)_] When man began to make tools he pounded one rock with another. He hoped he would knock off just the right chip in the right spot. This is called the percussion method of flaking (see illustration, page 91). Some say the Neanderthal was not content with this. They think that he must have discovered how to place a piece of bone or very hard wood against a flint at the point where he wanted to knock off a flake, and then strike it with a hammerstone (see illustration, page 92). This might account for the small chips, or “retouches,” taken off the edge of some of his spear points as in the illustration below. Even the Acheuleans are occasionally credited with this invention because many of their hand axes are so symmetrical. There are those who say that the Neanderthal had progressed so far in flint work that he knew the art of pressure flaking—the third step in flint knapping—which involved the pressing off of small chips with the bit of wood or bone held in the hand (see illustration, page 93). It seems more likely that Neanderthals and men of Acheulean times used the anvil method of percussion flaking (lower drawing, page 91), not an inaccurate way of knocking off small chips. [Illustration: PERCUSSION FLAKING _The first method by which early man shaped his tools. (After Holmes, 1919.)_] [Illustration: THE SECOND STEP IN FLINT KNAPPING _For more accurate work, early man applied a small stick of hardwood or a piece of bone at the proper spot and hit the interposed tool with a mallet of heavy wood or a rock. No one knows who invented this technique—Acheulean, Neanderthal, or later man. (After Holmes, 1919.)_] [Illustration: THE THIRD STEP—PRESSURE FLAKING _The discovery that gave early man complete control over the shaping of flints was that a slow and continued pressure would dislodge just the flake he desired. Above, we see how he worked on a small point, and below, to the left, how he chipped thin slivers from a core. (After Holmes, 1919.)_]