He said proudly, "That's how far we've got so far, heading north from the Niger. In the past, the desert actually came down to the side of the river in many places. The water was completely wasted. Now we've diverted it and are reforesting anywhere up to three miles a year." "Three miles a year," she scoffed. "You'll take five centuries." * * * * * He shook his head and grinned. "It's a progressive thing. Water is admittedly the big problem. But as our forests grow, they themselves bring up the moisture content of the climate. Down in this area--" he made a sweeping gesture over the map which took in large sections north of the Niger--"we've put in hundreds of millions of slash pine, which is particularly good for sandy soil and fast growing. In ten years you've gone from two-year-old seedlings to a respectable forest." Johnny pointed out Bidon Cinq on the map. "At the same time we found what amounts to a subterranean sea in this area. Not a real sea, of course, but a water-bearing formation or aquifer, deep down under the surface of the earth--layers of rock and gravel in which large quantities of water are lying. The hydro-geological technicians who surveyed it estimate that it holds reserves of several billion tons of water. Utilizing it, we've put in several hundred square miles of seedlings and transplants of various varieties. Where there are natural oases, of course, we stress a lot of date palm. In rocky areas it's _acacia tortila_. In the mountains we sometimes use varieties of the pinyon--they'll take quite a beating but are a little on the slow-growing side." She was looking at him from the sides of her eyes. "You're all taken up by this, aren't you Mr. McCord?" Johnny said, surprise in his voice. "Why, it's my work." Derek came sauntering in and scaled his sun helmet onto his own desk. "Good morning, Mademoiselle," he said. And to Johnny, "Hiram, that city slicker from Timbuktu just came up with his posse." Hélène said, "What is this _Si_, _Hiram_ and _Reuben_ which you call each other?" Johnny smiled sourly, "In a way, Miss Desage, this is just one great tree farm. And all of us are farmers. So we make jokes about it." He thought for a moment. "Derek, possibly you better take over with Mohammed. I want to get over to In Ziza with Reuben." "To see about the pumps?" Hélène said innocently. Johnny frowned but was saved from an answer by the entrance of Mohammed Mohmoud. He was dark as a Saharan becomes dark, his original Berber blood to be seen only in his facial characteristics. He wore the rather flamboyant Mali Federation desert uniform with an air. When he saw the girl, his eyebrows rose and he made the Moslem salaam with a sweeping flourish. Johnny said, "Mademoiselle Desage, may I present Captain Mohammed Mohmoud ould Cheikh, of the Mali desert patrol." He added sourly, "The officer in charge of preventing nomads from filtering up from the south into our infant forests."