"Our wells are about thirty feet deep," said Frank. "In a dry time there's no water in them." "How is it when you have a long wet spell?" "They are more than half full then." "Have both wells the same depth?" "I think so." "Where does the water in the wells come from?" "It is the rain that has soaked into the ground," said Frank. "How far down does it go?" "It must go down till it finds some hard clay or rock that stops it," said Frank. "What does it do then?" "Then," said Frank slowly, "it must go along on top of the rock or clay." "When does it come out of the ground?" "Oh, I see! The rain goes down until it comes to that lime rock. Then it goes along the rock, and comes out there," said Donald, pointing to the spring. "Does it always?" asked Frank. "I have read of very deep wells that are bored down into the ground more than a thousand feet, and when the augur strikes water the water comes right up to the top of the ground." "You are talking about artesian wells," said Uncle Robert. "Yes, that is the name." [Illustration: Section of hillside.] They had left the spring and were walking down toward the mouth of the creek. The rain had swollen the little stream, and the water was dark with dirt. "See how muddy the water is," said Susie. "The creek must bring down a lot of earth," said Frank. "There are Joe and Dick Davis," said Donald, pointing across the river. "I wonder what they are doing? I'm going to see." Donald ran along to the mouth of the creek, which he reached as the Davis boys began to scramble down the steep bank to the edge of the river. "Hello there!" called Donald. "What are you fellows doing?" "Sticking in the mud," replied Joe Davis, holding up first one foot and then the other, heavy with the stiff clay that hung to it. "Why don't they go around by the path?" said Susie, coming up with Frank and Uncle Robert. "They'll always take the short cut if there is one," laughed Frank. "Come along over here!" he shouted. "All right," sang out Dick, scraping the mud from his shoes. An eddy in the stream just above the steep bank made a quiet place in the current. Here their boat was moored. As they pushed out from the shore they were swept down the stream, but a few strong pulls carried them beyond the swiftest part of the current, and then they easily rowed back to the landing at the mouth of the creek, where the Leonards were waiting for them. "I wish our bank was low like this," said Joe as he leaped from the boat. "We have to go so far downstream before we find a low bank on our side." "I should think you'd rather walk a mile," said Susie, looking at Joe's shoes, "than come down that bank when it's so muddy." "Humph! we don't mind a little mud," said Dick, wiping his feet on the grass. "You've brought some of your land over to us, I see," laughed Uncle Robert. "Mr. Leonard will be obliged to you. He is always glad when the soil is left on his side."