As for the doctor, he came upon Rolla when the woman was deep in an experiment. She stood in front of a rude trough, one of perhaps twenty located within a large, high-walled inclosure. In the trough was a quantity of earth, through the surface of which some tiny green shoots were beginning to show. Rolla inspected the shoots, and then, with her stone knife, she made a final notch in the wood on the edge of the trough. There were twenty-odd of these notches; whereas, on other troughs which the doctor had a chance to see, there were over thirty in many cases, and still no shoots. The place, then, was an experimental station. This was proven by Rolla's next move. She went outside the yard and studied five heaps of soil, each of a different appearance, also three smaller piles of pulverized mineral--nitrates, for all that the doctor knew. And before Kinney severed his connection with the Sanusian, she had begun the task of mixing up a fresh combination of these ingredients in a new trough. In the midst of this she heard a sound; and turning about, waved a hand excitedly toward a distant figure on the far side of a nearby field. Meanwhile Smith had managed to get in touch with Dulnop. He found the young man engaged in work which did not, at first, become clear to the engineer. Then he saw that the chap was simply sorting over big piles of broken rock, selecting certain fragments which he placed in separate heaps. Not far away two assistants were pounding these fragments to powder, using rude pestles, in great, nature-made mortars--"pot-holes," from some river-bed. It was this powder, beyond a doubt, that Rolla was using in her work. To Smith, Dulnop's task seemed like a ridiculously simple occupation for a nearly grown man, until he reflected that these aborigines were exactly like toddling children in intellects. Van Emmon had no trouble in making connections with Corrus. The herdsman was in charge of a dozen cows, wild looking creatures which would have been far too much for the man had they been horned, which they were not. He handled them by sheer force, using the great club he always carried. Once while Van Emmon was watching, a cow tried to break away from the group; but Corrus, with an agility amazing in so short and heavy a man, dashed after the creature and tapped her lightly on the top of her head. Dazed and contrite, she followed him meekly back into the herd. The place was on the edge of a meadow, at the beginning of what looked like a grain field. Stopping here, Corrus threw a hand to his mouth and gave a ringing shout. Immediately it was answered, faintly, by another at a distance; and then Van Emmon made out the form of Rolla among some huts on the other side of the grain. She beckoned toward the herdsman, and he took a half-dozen steps toward her.